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COMPUTER OPERATIONS & 
PACKAGES 
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COMPUTER OPERATIONS & PACKAGES 
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DEFINE A COMPUTER 
 An electronic machine that works under the control of stored programs to accept, process 
 output data/information for use by the operator. 
 A device that accepts data, processes the data in accordance with a stored program, 
generates results, and usually consists of input, output, storage, and arithmetic, logic, and 
control units. 
 A functional unit that can perform substantial computation, including numerous arithmetic 
operations or logic operations, without human intervention during a run. 
 It is an electronic device/machine that accepts data(raw facts  figures) asinput and 
processes (works on it) to produce information(data converted tomeaningful form) as 
output. 
A computer performs a number of functions: 
• Input (Data) 
The computer accepts data from outside for processing. Input is the raw information 
entered into a computer from the input devices. 
• Processing 
The computer performs operations on the data that it holds internally. Processing is the 
operation of data as per given instruction. It is totally internal process of the computer 
system. 
• Output 
The computer produces information for external use. Output is the processed data given 
by computer after data processing. Output is also called as Result. We can save these 
results in the storage devices for the future use. 
• Storage 
The computer stores data before, during and after processing. 
• Communication 
The computer can send or receive data to or from other computers when it is connected 
on a network 
The computer is made up of hardware, software and peripheral devices. 
Hardware- refers to the tangible, physical and mechanical components of a computer. 
Software- refers to the intangible computer components, which are the programs or instructions of 
the computer. Everything that a computer does, it acts under instructions written out as computer 
programs. The hardware needs these instructions to function 
Computer program: 
• A set of instructions, written in a specific programming language, which a computer 
follows in processing data, performing an operation, or solving a logical problem. See also 
software. 
• A computer program is a set of statements or instructions to be used directly or indirectly in 
a computer in order to bring about a certain result. 
NB: Software alone is useless, so is the hardware. The two are inseparable. 
Peripheral Devices- These are devices that are external (not part of the computer) but can be 
connected to a computer. They are not essential for the functioning of the computer but can be
COMPUTER OPERATIONS  PACKAGES 
connected to the computer for specific reasons. Examples are scanners, modems, printers, 
speakers, digital cameras, etc. 
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DATA PROCESSING 
Used specifically, data processing may refer to a discrete step in the information processing cycle 
in which data is acquired, entered, validated, processed, stored, and output, either in response to 
queries or in the form of routine reports; the processing is the step that organizes the information in 
order to form the desired output. Used in a more general sense, data processing may also refer to 
the act of recording or otherwise handling one or more sets of data, and is often performed with 
the use of computers. The word data is commonly used to mean “information” and often suggests 
large amounts of information in a standardized format. Data may consist of letters, numbers, 
equations, dates, images, and other material, but does not usually include entire words. 
CATEGORIES OF DATA PROCESSING 
Data is processed to get the required results. Different operations may be performed on data. 
Therefore, data processing is defined as: 
A sequence of operations on data to convert it into useful information is called data processing. 
The important operations that can be performed on data are: 
• Arithmetic and logical operations on data to get required results. 
• To send and receive data from one location to another. 
• Classification of data. 
• Arranging data into a specific order etc. 
The data processing is divided into three categories or levels. 
1. Manual Data Processing 
In manual data processing, data is processed manually without using any machine or tool to get 
required result. In manual data processing, all the calculations and logical operations are manually 
performed on the data. Similarly, data is manually transferred from one place to another. This 
method of data processing is very slow and errors may occur in the output. 
In Zimbabwe, data is still processed manually in many small business firms as well as government 
offices  institutions. 
In manual data processing data is processed manually. No machine or tool is used. 
All the calculations on data are performed manually. This is a slow method and errors may occur. 
This is an old method. It was used before the invention of calculators. But data is still processed 
manually in many small shops.
COMPUTER OPERATIONS  PACKAGES 
Example: A book seller (a small book shop) records his daily transactions manually. He prepares bills 
by pen, paper and carbon paper (no doubt, brain is the main data processor in this case). At the 
end of day he will use carbon copies made on a particular date to know how many books he sold 
and how much income he got. 
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2. Mechanical Data Processing 
In mechanical data processing, data is processed by using different tools like calculators or other 
mechanical devices. This method of data processing is faster and more accurate than manual 
data processing. 
Mechanical data processing is more accurate than manual. Calculators, computer programs and 
other devices are used on the data however someone still has to step in between operations. 
In mechanical data processing data is processed with the help of devices or machines. These 
machines that help the people in data processing may be calculators and type writers etc. 
Obviously, this method is faster easier and more accurate than manual data processing. 
Example: Book seller can use a calculator to speed up his data processing system. There will be a 
less chance of errors in calculations. Bill calculations will be much more faster with a calculator and 
easier too. 
3. Electronic Data Processing 
It is the modern technique to process data. The data is processed through computer. Data and set 
of instructions are given to the computer as input and the computer automatically processes the 
data according to the given set of instructions. 
The computer is also known as electronic data processing machine. This method of processing 
data is very fast and accurate. Now-a-days, the data is processed and analyzed through 
computers. For example, the results of students are prepared through computer; in banks accounts 
of customers are processed through computers etc.
COMPUTER OPERATIONS  PACKAGES 
It is the latest and fastest method of data processing. Data is processed with the help of computer. 
First of all, data and set of instructions are given to the computer. Computer gives output results 
after processing the data according to instructions. This method of data processing is very fast and 
accurate. Electronic data processing is used in banks and business firms, Government offices, 
colleges, schools, universities, businesses and other institutes. Electronic data processing is being 
used in almost every field of life. Example: Suppose there are 800 students in a college. There is a 
manual library system in this college. If we want to know which students have not returned books 
since one year? We will have to search registers for 800 students’ record. But computer can do this 
job within seconds. 
In short, we can say that: Electronic data processing: 
i) is more fast 
ii) is less time consuming 
iii) can process large amounts of data easily 
iv) can present information in more attractive way 
v) will give 100 % error free results, if input and instructions are accurate. 
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THE DATA PROCESSING CYCLE 
The data processing cycle is the order in which data is processed. There are four stages:- 
After collecting data, it is processed to convert into information. The data is processed again and 
again until accurate result is achieved. This is called data processing cycle. 
Data processing cycle involves following three basic activities:
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1. Input 
2. Processing 
3. Output 
1. INPUT 
It is the process in which collected data is given to computer after converting into binary form. 
Input step can be further divided into following steps: 
i) Planning 
Here objectives of data processing are defined. For example, in examination system, objective is to 
process student examination data to get result cards. 
ii) Data Collecting 
Here data is collected. Data is the raw material for data processing. This must be accurate for 
getting accurate results. 
iii) Input 
Here data is entered into computer. 
iv)Verification 
Here collected data is verified to determine whether it is valid for processing. For example marks 
must be in numeric form. 
v) Coding 
Data is stored in computer in binary form. Here data is converted (or coded) into computer 
readable (binary) form. 
2. PROCESSING 
Now data is ready for processing. We process collected data to convert into information. Some 
important activities in processing are as following: 
i) Data Classification 
Here data is classified into different groups or sub-groups. So that it can be handled easily and 
separately. For example if we collect data about students of a college we will divide them into 
D.Com and B.Com class groups. 
ii) Data Sorting 
Here data is arranged in some order. So that it can be accessed quickly. For example we can sort 
student data by Roll number or name. 
iii) Data Calculation/Processing
COMPUTER OPERATIONS  PACKAGES 
Here arithmetic and logical operations are performed on data to get the required result. For 
example total marks of each student are calculated. 
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3. OUTPUT 
After completing the processing, output is received. Output step involves following steps: 
i) Testing 
The results are tested to find if they are according to requirements. And any errors are removed. If 
results are not satisfactory then we repeat above-mentioned steps again and again until the 
accurate results are found. 
ii) Summarizing 
Huge results are summarized to make them short and precise. 
iii) Storing results 
The results are stored properly on secondary storage devices for future use. 
iv)Output the result 
Here output is produced as softcopy on screen or as hard copy as printout. Information is sent to 
different places as needed. 
v) Feed Back 
In this step we take comments from users about output results. If results are not satisfactory then we 
repeat above-mentioned steps again and again until the accurate results are found. 
What is the Information Processing Cycle? 
If one has to look at the information processing cycle diagram, he will see that there are four 
events in the sequence of events. The sequence of events, which make up the cycle are: 
Input 
Processing 
Output 
Storage
COMPUTER OPERATIONS  PACKAGES 
In some of the events, certain sub-events can also be added. Without wasting any more time we 
will turn towards the cycle in detail. 
Input 
This is the first event in the cycle. This stage involves collection of data from the outside or also from 
within the system. One can break this stage into three more stages, namely acquisition, data entry 
and validation. After the data has been acquired from the source, it is entered into the current 
system, upon which the data is validated, so that correct results are given at the end of the cycle. 
The input devices are many. The commonly used input devices are computer keyboard, bar code 
readers, scanners, output from another system, etc. 
Processing 
In this stage the computer processes the minutest details entered. This processing makes the data 
entered usable. If the computer was not to process the data, it would not be of any use and it 
would also be a big mess of data. For example, if the spreadsheet was not to process the data, 
then the data in the spreadsheet would only be a mess of numbers. The spreadsheet is a program 
which gives the data out back to the user in the usable form. The system used for processing, along 
with the data entered will decide the kind of output, which the user will get. 
Output 
If you have to look at the diagram of information processing cycle, the step after processing is the 
output stage. The processed information is now transmitted to the user. This stage can also be 
further divided. After processing the data, there can be further interactive queries asked or routine 
reports can be given. There are different forms in which the output can be given to the user. There 
can be print report, which may be given to the user. The output can also be given in the form of 
audio, video as well. In some cases, the results may only be displayed on the computer monitor. 
Storage 
After the data has been processed, along with the output to the user, the data is also stored. 
Different computer storage devices can be used for the same. Some of the commonly used data 
storage methods are disk storage, tertiary storage, etc. Storing the data also serves another 
purpose. You will not have to repeat the entire cycle again. Often the storage is done in both 
digital as well as hard copy format. At the same time, backup of the digital format is also 
maintained, which can be retrieved in case of system crash. 
The most important advantage of this cycle is that the information is processed quickly. At the 
same time retrieving the data is an easy task as well. The processed information can further be 
passed unto the next stage directly in case the need be. The necessary data is stored, which helps 
in avoiding duplication of data as well as time. 
ATTRIBUTES OF GOOD INFORMATION 
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Quality 
Required 
Commentary 
Relevant The information obtained and used should be needed for decision-making. it 
doesn't matter how interesting it is. Businesses are often criticised for producing too 
much information simply because their information systems can do it. A good way 
of ensuring relevance is to closely define the objectives of any information reports. 
Another way to improve relevance is to produce information that focuses on 
exceptions - e.g. problems, high or low values, where limits have been exceeded. 
Up-to-date Information needs to be timely if it is to be actioned. For example, the manager of 
a large retail business needs daily information on how stores are performing, which 
products are selling well (or not) so that immediate action can be taken. To 
improve the speed with which information is produced, businesses usually need to 
look at upgrading or replacing their information systems.
COMPUTER OPERATIONS  PACKAGES 
Accurate As far as possible, information should be free from errors (e.g. the figures add up; 
data is allocated to the correct categories). The users of information should be 
informed whenever assumptions or estimates have been used. Accruate 
information is usually a function of accurate data collection. If information needs to 
be extremely accurate, then more time needs to be allocated for it to be checked. 
However, businesses need to guard against trying to produce perfect information 
- it is often more important for the information to be up-to-date than perfect. 
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Meet the 
needs of the 
User 
Users of information have different needs. The managing director doesn't have time 
to trawl through thick printouts of each week's production or sales listings - he or she 
wants a summary of the key facts. The quality control supervisor will want detailed 
information about quality testing results rather than a brief one-line summary of how 
things are going. It is a good idea to encourage users to help develop the style and 
format of information reporting that they require. 
Easy to use 
and 
understand 
Information should be clearly presented (e.g. use summaries, charts) and not too 
long. It also needs to be communicated using an appropriate medium (e.g. email, 
printed report, presentation. Businesses should also consider developing templates 
which are used consistently throughout the organisation - so that users get used to 
seeing information in a similar style. 
Worth the cost Often forgotten. Information costs money. Data is costly to collect, analyse and 
report. Information takes time to read and assimilate. All users should question 
whether the information they recieve/have requested is worthwhile 
Reliable Information should come from authoritative sources. It is good practice to quote 
the source used - whether it be internal or external sources. If estimates or 
assumptions have been applied, these should be clearly stated and explained. 
1) Valid 
2) Fit for use 
3) Accessible 
4) Cost effective 
5) Understandable 
6) Time 
DATA 
 Relationship between Data and Information 
 Data is raw information 
 a collection of facts from which conclusions may be drawn; statistical data 
INFORMATION 
 Data that has been processed to add or create meaning and hopefully 
knowledge for the person who receives it. Information is the output of information 
systems. 
 Organized data which is understood to have significance and meaning 
 Methods of data collection {see Systems Analysis  Design} 
 Questionnaires 
 Observation 
 Sampling 
 Interviews 
 Written documents  research 
MAKE NOTES ON: 
 Verification 
o The act of reviewing, inspecting, testing, checking, auditing, or otherwise establishing 
and documenting whether items, processes, services, or documents conform to 
specified requirements. 
o An effort to test the accuracy of the questionnaire response data. The concern is 
uniquely with data accuracy and deals with neither the reliability nor the validity of 
measures. 
 Validation
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o The process of evaluating software at the end of the software development process to 
ensure compliance with software requirements. The techniques for validation are 
testing, inspection and reviewing. 
o Determination of the correctness of the products of software development with 
respect to the user needs and requirements. 
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BENEFITS OF COMPUTERS 
With the advent of new technology, various processes have been very dependent with 
automation. As the years go by, more and more inventions are introduced in the market and in the 
society all for one purpose - convenience. Let us tackle for instance two of the most influential 
aspects of this modern world; the societal and the entrepreneurial feature. These two have been 
greatly influenced by the advancements that are continuously taking place. With that said, a 
number of essential advantages are becoming more evident in these two facets. To further draw a 
clearer picture on the benefits of computers on each of the mentioned aspect, here are brief 
descriptions of each. 
Business 
Multitasking - The modern multimedia options enable entrepreneurs to work various tasks all at the 
same time. Workers in the offices can use the DVD-ROM while installing Printer Cartridges and 
running a scan thus making workload easier and more convenient. With such, the need for an 
outsourcing company would not be essential because all the tasks can be addressed by majority 
of the manpower available. 
Cost-effective - These computers have allowed companies to cut costs on payroll and individual 
office equipment. Because of the efficient and fast outputs coupled with less expenditures on 
operations, revenues are then maximized. Good examples for this benefit are the email messaging 
that lessens postage costs and video conferencing that decreases travel allowances for 
employees. 
Increased access to the market - Because of the Internet, businesses have opened their doors to 
various opportunities all around the globe. For those selling goods, then customers can readily 
purchase them over the Web thus resulting to an increase in the sales of the firm. Also, advertising 
strategies are well utilized because by just simply posting a good multimedia scheme over the 
Web, firms can readily maximize their marketing plans. 
Organization- Different types of software are utilized to store a wide array of documents that must 
be kept confidential for years. With the help of computers, storage and retrieval of files are easily 
done with just a click of the mouse. 
Those are the benefits that businesses are enjoying from the various innovations in computers now. 
Further, here are the societal advantages. 
Education edge- Nowadays, PC's enable students to search from a wide range of online resources. 
Hence, they can save time on looking for the best Internet source that can answer each of the 
queries. Instead of spending so much time looking for books, then this could answer the worries for 
students who want to hasten their tasks. Also, a new trend in education is online teaching. Through 
the Web, people can freely enroll in a specific course provided that you get to pay the fees on the 
specified date. This scheme can be very helpful for individuals who want to get a degree yet are 
to busy to get into the usual classroom setting. 
Communication benefit- Social networking sites, chat, and video conferencing sites are accessible 
because of computers. People across the globe can now talk to their loved ones in real time with
COMPUTER OPERATIONS  PACKAGES 
the help of these gadgets. What is good about this communication option is that it is more cost 
effective than the usual telephone. By embracing such, people can now deliver messages and 
create a copy of that using quality printer cartridge in just a second. 
Job opportunities- These gadgets open up a wide array of workload for people. That is, experts are 
needed in software and hardware maintenance and checks. With the increasing demand for 
these professionals, unemployment is then lessened at a considerable percentage. 
Home Entertainment- During weekends, you may utilize your personal computer to watch films 
using its DVD-ROM. Aside from this, you may as well play games all throughout the day. You can 
simply install a variety of files that you can use for the whole day of indoor fun. From the latest TV 
shows to the more modern games, you can have them in your CPU just minutes. 
Those are few of the numerous benefits of personal computers in our everyday lives. Knowing each 
of those points will certainly allow you to see the importance of those gadgets in almost all 
processes that are taking place every day. 
With this obvious dependence, it is also but essential to ensure that each of the systems are 
working properly. This is because a single defect inside the CPU could mean serious impairment. 
Hence, the specialists in repairs and maintenance can be tapped for their expertise. 
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ADDITIONAL 
Without computers, there would be no Internet. Computers and the internet helped create a 
global community where it is possible to instantly communicate with anyone around the globe. 
You aren't just stuck being exposed to only those in your own community or country. 
Various online knowledge sources including online encyclopaedias, open vast amounts of 
information to people all over the world. This can even aid someone doing anything from a simple 
homework assignment, to a complex research paper. 
In the home, you can pay your bills online, without having to write a check or placing the bill in a 
postage envelope. No chance of the payment getting lost in the mail, and no need to worry 
about being assessed a late charge - as the bill has been paid and confirmed. People now listen 
to music, get up to the minute live news reports, play games, watch movies, and even watch 
television shows they might have missed. 
You can buy products online that may not be available in your local shops. 
Computer chips are used in many many things, including the portable cell-phone. And the internet 
led to Twitter, which was used recently by Iranians keeping communication and coordination 
active against an oppressive regime. 
In the business world, computers are used in every operation, function and activity of an 
organization. This had led to improved productivity, greater collaboration, major improvements to 
information management. 
Computers help scientists calculate things faster and learn more about the world and universe. In 
addition, this helps things get invented, like a video game system. 
Computers are used heavily to improve accuracy, flexibility of planning, and speed in Engineering 
work. Civil Engineering - Autocad and WaterCad.Mining engineering - Surface Deformation 
Prediction Software.Mechanical engineering - SolidCad. Electrical Engineering - electric cycle 
programs. 
In the medical community, computers led to improved Hospital care. So in a sense, computers 
have even helped extend the average lifespan of human beings.
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LIMITATIONS 
1. They are expensive. 
2. If you have little knowledge of them, it is easy to get in a lot of trouble and quite literally destroy 
your computer. 
3. Depending on the OS and software/hardware installed, they can be difficult to maintain. 
4. If you have the internet and don't have an Anti-Virus program, or at least an Anti-Spyware 
program, surfing the web can ruin your day. 
5. Nothing lasts forever. 
Computer disadvantages are as follows; Violation of Privacy, it is crucial that personal and 
confidential records stored in computers be protected properly. Impact on Labor Force, although 
computers have improved productivity and created an entire industry with hundreds of thousands 
of new jobs, the skills of hundreds of thousands employees are replaced by computers. Health 
Risks, prolonged or improper computer use can lead to head injuries or disorders. Computer users 
can protect themselves from health risks through proper workplace design, good posture while at 
the computer, and appropriately spaced work breaks. Impact on the Environment, Computer 
manufacturing processes and computer waste are depleting natural resources and polluting the 
environment. 
MAJOR COMPONENTS OF A COMPUTER SYSTEM 
CPU 
The CPU consists of the ALU  CU 
KEY 
Data Instructions 
Command Flow 
Control unit-issues 
commands to computer 
elements  interpret stored 
instructions 
A. L.U. performs 
arithmetic  logic 
operations 
Output Unit 
Information after 
processing 
Main Memory-Holds 
data  instructions  results 
ofprocessing 
-RAM 
Input Unit 
Data  instructions 
Backing/Auxiliary 
Storage- supplements the 
main storage.
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DESCRIBE THE FUNCTIONS OF EACH COMPONENT. 
Main memory Auxiliary or backup storage 
Stores programs and data while computer is running 
for current use 
Store data or programs for later use 
Main memory is fast and limited in capacity Slow and capacity vary 
Cannot retain information when the computer is 
Non volatile 
switched off - Volatile 
Memory directly connected to the CPU - not portable Portable- can be transported from one 
machine to another. 
Primary storage Secondary storage 
PROVIDES FAST ACCESS ACCESS IS SLOW 
Temporary Permanent 
Computer cannot do or work without Can do or work without 
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PROCESSING DEVICE 
The only processing device on a computer is The Central Processing unit known as the CPU. It is the 
main part of the computer as all other devices are built around it. It can be referred to as the heart 
or brain behind the computer. 
Functions of the Central Processing Unit (CPU) 
a) It interprets the instruction in the program according to the type and sequence of 
processing operations that are to be performed on input data. 
b) Performs the varied arithmetic and logic operations that are necessary to convert 
input data into output information. 
c) Stores intermediate results of data being processed on its registers. 
d) Directs or controls output to all other devices (input, output, auxiliary storage units), 
telling each what to do and when to do it. 
CPU COMPONENTS 
It consists of the control unit (CU) and Arithmetic and Logic Unit (ALU). In most computers 
the two components - CU and ALU units - are combined in a unit called the 
microprocessor (CPU). 
The Control Unit 
The Control Unit manages input/output to and from the main memory and to and from 
auxiliary storage units and output devices. It interprets instructions in their sequence,It 
determines what is to be done to follow the instruction and, transmits to the appropriate 
device directions specifying the work to be done. For example, it advises each input 
device what data to transfer, when to transfer it, and when to send the data. It arranges 
for data to move from the main memory to the ALU and spells out the calculating and 
logic operations that are to be performed, and then arranges to send the processed 
results to main storage or to an output device for printing or display. 
The ALU 
The Arithmetic Logical Unit has 2 functions i.e. to perform calculations and logic operations 
at a fast speed (measured in nanoseconds, i.e. billionths of a second). It consists of 
registers (special storage locations to hold the data to be processed), and an 
accumulator to store intermediate results of operations. Logic operations compare values 
for greater, smaller or equal. 
CPU speed
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The CPU speed is measured in Megahertz (MHz) being millions of instructions that can be 
executed per second (MIPS). Each computer has specified, the processor speed. 
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INPUT DEVICES 
These are some devices that feed data into the computer for processing. Some examples 
include:- 
1. KEYBOARD 
2. MOUSE 
3. TRACKBALL 
4. LIGHT PEN 
5. TOUCH SCREEN 
6. MODEM 
7. SCANNER 
8. MICROPHONE 
9. BAR CODE READER 
10. DIGITAL CAMERA 
11. VIDEO DIGITISER 
12. MAGNETIC INK CHARACTER RECOGNITION (MICR) 
13. MAGNETC STRIPS OR STRIPES READER 
14. KEY TO DISK 
15. GRAPHICS TABLET 
16. OCR 
17. OMR 
18. VOICE RECOGNITION SYSTEM 
Storage devices can be used as input devices 
a) KEYBOARD 
The keyboard is an input device with an arrangement of keys, like those on a typewriter, 
and an additional set of keys that fall into 5 basic categories: 
1. Function keys- keys form the first row of keys. They perform special operations in 
applications e.g. F7 activates Spell Checking Program in word processing and F1 
activates the Help facility in any application. 
2. Alphanumeric keys (like those on typewriter) are arranged in a QWERTY series. First 
is a row of numbers with some characters like %^*()@!~ above them, then letters 
of the alphabet, the spacebar at the bottom, the Shift key on both the left and 
right side of the Spacebar. 
3. Numeric keypad- serves 2 functions. At the top of the keypad is the NumLock key, 
which locks the keypad into Number mode when, pressed. When in Number 
mode, the keys function as number keys arranged like a standard calculator, 
otherwise it is in Cursor control mode, which allows you to move the cursor up, 
down, forward or backward by pressing the appropriate arrow key. When in cursor 
mode you can also use the home, page up, page down, end, delete and insert 
keys from Num Lock pad. 
4. Cursor control keys are the arrow keys as well as Home, End, Ins, Page Up etc. 
Their major function is to place the cursor in an appropriate position for reading, 
appending or editing text. 
5. Combination keys are the Shift Ctrl andAlt keys. On their own they are ineffective 
but combined with other keys they work. E.G. The Shift key, can be used to type to 
type the $ sign (you would keep Shift pressed as you press the $ sign key once). 
b) MOUSE
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The mouse is both input and pointing device. It is a hand held device with a rotating ball 
(trackball) underneath and Left  Right 
(the blinking item on your screen) around the screen and to click on objects. The trackball 
is made from a ball in a socket, which is used to move the cursor on a screen. The cursor 
moves in the direction the ball moves as it is rolled. 
c) JOYSTICK 
) buttons, which enable the user to move the cursor 
he device. A leverinputdevice that can be moved in many directions, 
The joystick is anInput device 
e.g. Up, Down, Left or Right. It is normally used with computer games to control the 
movements of objects on the screen. 
d) LIGHT PEN 
This is an Inputdevice. An electricaldeviceused with a monitor 
ordinary pen. One writes on a monitor with it and it senses the light from the position on the 
screen and transmits the information to the computer. 
e) TOUCH-SENSITIVE SCREEN/ TOUCH PAD 
Input deviceused in public information kiosks 
point of interest to get what (s 
Touchpad 
A small pressure- and motion 
move the mouse pointer. When you move your finger across the pad, the mouse pointer 
on the screen moves in the same direction. A touchpad is an alternative to a mouse. 
A touchpad is operated by using your finger and dragging it across a flat surface; as yo 
move your finger on the surface, the mouse cursor will move in that same direction, and 
like most computer mice, the touchpad also has two buttons below the touch surface that 
enables you to click like a standard mouse. 
f) SCANNER – Input device 
It works like a photocopier but copies an image from text to computer mode 
need for OCR (Optical Character Recognition) software to change the text into digital 
form, and to be able to modify the scanned image. 
g) MICROPHONE 
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monitor. It has the shape of an 
SITIVE kiosks. Theuser simply touches the screen at the 
s) he wants. 
motion-sensitive area on a portable computer that you can use to 
ks 14 
you 
mode. There is
COMPUTER OPERATIONS  PACKAGES 
This is Input device. This is 
words are into digital mode for storage. The sound can be played back. 
h) DIGITAL CAMERA 
used in conjunction with voice recognition programs. It converts 
This is Input device. It works like a standard camera except that it does not use 
photographic film. The images are recorded digitally in the camera’s memory. Images are 
transferred onto the computer, and can be printed. 
MORE INPUT DEVICES 
1. KEY TO DISK- An early stand-computer 
-alone data entry machine that stored data on magnetic 
entry. The key to disk 
machine was the successor to the key-to-tape machine, which 
was the first major breakthrough in data entry since the punch card. 
2. BARCODE READER 
Barcodes are different groups of vertical bars that can be read by an optical 
Barcodes are printed on nearly every product that you can buy. Shops use barcodes 
because they are cheap to produce and very durable. 
3. CONCEPT KEYBOARD 
This is a flat board that contains a grid of buttons. Each button can be programmed to 
follow instructions. An overlay sheet is placed on the grid with an explanation for each 
button. They are used in primary schools with young children. Many mod 
restaurants have overlays with either a description or picture of the meals that are 
available to make ordering easier. 
4. DIGITAL CAMERA 
A digital camera allows you to take pictures and to store a digital photographic image 
that can be read by a computer. You can then transfer the images directly from your 
camera on to your computer. 
5. GRAPHICS TABLET 
This consists of a flat pad (the tablet) on which the user draws with a special pen. As the 
user draws on the pad the image is created on the screen. Using a graphics tablet a 
designer can produce very accurate on 
6. MICR (MAGNETIC INK CHARACTER READER) 
Magnetic ink characters are the strange looking numbers that appear at the bottom of 
cheques. These characters are used because they are very difficult to forge or damage. 
Banks use MICR to read the numbers from the bottom of cheques to obtain 
account numbers and bank sort codes. 
7. MAGNETIC STRIP (OR STRIPE) READER 
Magnetic strips are built into many plastic cards such as 
point cards and personal identity cards. The magnetic strip on the back of the card can 
hold the personal details of the card owner and, with the necessary PIN, will allow access 
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modern fast food 
on-screen drawings. 
data 
cheque guarantee cards, cash 
15 
disk for 
scanner. 
ern such as 
cash-point
COMPUTER OPERATIONS  PACKAGES 
to secure information e.g. bank account details 
input into a computer system by a reader. 
details. Data stored on the strip is scanned and 
8. MIDI (MUSICAL INSTRUMENT DIGITAL INTERFACE 
INTERFACE) 
A MIDI system allows you to attach a musical instrument to your computer, for example a 
musical keyboard. You can then store a 
the computer play it back to you. 
9. OMR (OPTICAL MARK READER 
musical sequence on a computer and then have 
READER) 
An OMR reads marks made by pencil on a printed form into the computer. OMR systems 
are suited to reading pre 
selection sheets and multiple 
OMR processing is popular for tests, where students receive a special card containing 
several empty circles and a packet that contains the questions and possible answers to 
each of the questions. The student must complete the test by using a pencil to fill in each 
blank circle with what he or she believes is the correct answer. For example, if the answer is 
B, the student would have to fill in the B Circle in order to get the answer 
10. SCANNER 
pre-printed forms and check-boxes such as National Lottery number 
multiple-choice exam papers. 
Hardware input device that allows a user to take an image or text and convert it into a 
digital file, allowing the computer to read or display the scanned object. A scanner is 
commonly connected to a computer USB, Firewire, Parallel, or SCSI port. 
a cheap and common way of getting images into a computer. They can also be used 
with OCR (Optical Character Recognition) softw 
11. TOUCH SCREEN 
A touch screen is a special type of 
crossing the screen. When the screen is touched (usually to choose an on 
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correct. 
Scanners 
software to scan in text. 
VDU, which has a grid of light beams or fine wires criss 
on-screen option), 
16 
. tional are now 
, criss-screen
COMPUTER OPERATIONS  PACKAGES 
the computer senses where you have pressed. Due to the vast amount of information they 
can store, touch screen operated computers are generally used in the provision of public 
information and are found in places such as airports. 
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12. VIDEO DIGITISER 
A video digitizer takes an image from a video camera or television and converts it so that 
it can be used by, and stored on, a computer. Video sequences captured using a video 
digitizer is often used in multimedia presentations. 
13. VOICE RECOGNITION SYSTEM 
A microphone is used with a voice recognition system. This can be used with a word 
processing program to enter text. It can also be used as part of security systems - only 
certain digitally stored voices have access. 
TEXT INPUT DEVICES 
• Chorded keyboard ,GKOS keyboard ,Keyer ,Telegraph key 
(~20 WPMMorse code) 
• Vibroplex (30–80 WPM Morse) ,Keyboard, Typing ,Computer 
keyboard 
• Handwriting recognition ,Optical character recognition 
,Speech recognition 
POINTING DEVICES 
• Light pen,Light gun,Cyberglove ,Touch screen ,Head 
pointer ,Eye gaze/eye tracking 
• Computer mouse ,Trackball ,Touchpad ,Pointing stick 
,Graphics tablet (or digitizing tablet) ,Stylus 
GAMING DEVICES 
• paddle, Power Pad, Joystick ,Gamepad (or joypad) 
IMAGE, VIDEO INPUT 
DEVICES 
• Digital camcorder ,Webcam, Digital video recorder,Image 
scanner 
• 3D scanner ,Digital camera 
AUDIO INPUT DEVICES 
• Microphone (see also speech recognition) ,Digital audio 
recorder ,Digital dictaphone 
OUTPUT DEVICES 
1. LOUD SPEAKER 
Allows a user to hear sounds and music from the computer provided the system has 
installed a sound card. 
2. MODEM 
An Input/ Output electronic device with circuits which changes data to be transmitted 
from its machine form (digital form) into a form suitable for transmission over the 
telephone line (analogue form). At the receiving end it converts data vice-versa. It is 
only necessary when one needs to communicate information over a long distance 
and when connected to the internet. 
3. HEADPHONES
COMPUTER OPERATIONS  PACKAGES 
Headphones give sound output from the computer. 
except they are worn on the ears so only one person can hear the output at a time 
4. PLOTTERS 
A plotter can be used to 
They are usually used for Computer Aided Design ( 
Manufacture (CAM) applications such as 
Plotters: 
How it works: • A drum plotter 
the surface of a sheet of paper. 
• One high precision motor moves the pen from side to 
side. 
• Another high precision motor moves the paper 
backwards and forwards. 
• An electromagnet lifts and drops different coloured 
ink pens onto the paper to draw lines. 
• A flat 
• pen in the X direction and one to move it in the Y direction. 
• The paper does not move. 
Suitable uses: • Plotters are restricted to line drawing and can only create a solid 
region of colour by drawing a number of close, regular lines. 
• Plotters are often used in science and engineering applications for 
drawing building 
Advantages: • They are 
standard printers. 
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They are similar to speakers, 
produce high quality, accurate, A3 size or bigger drawings. 
CAD) and Computer Aided 
printing out plans for houses or car parts. 
prints by moving a pen sideways over 
flat-bed plotter uses two high precision motors, one to move the 
plans, printed circuit boards and machine parts. 
accurate and can produce far larger printoutsthan 
18 
) than
COMPUTER OPERATIONS  PACKAGES 
Disadvantages: • Slow and relatively expensive compared to printers. 
• They cannot print raster (photographic) images. 
• They can only fill solid blocks of colour using closely hatched lines. 
rmmakaha@gmail.com 19 
5. SPEAKER 
A speaker gives you sound output from your computer. Some speakers are built 
into the computer and some are separate 
6. VDU (Visual Display Unit) 
The VDU is output device. It displays images and text in colour or black and white as it. 
It displays results of processing. It is also called a monitor. 
7. PRINTERS 
It produces output on paper i.e. hard copy or on other print-key media. The 2 types of 
printers are impact and non-impact. 
Impact printers 
The printing device being a series of pins have a direct impact on the paper. The pins 
form characters on the paper by pressing a printing element and an inked ribbon 
against paper. An example of such a printer is the Dot Matrix. The printers are 
reasonably fast, inexpensive and can produce both text and graphics. They also 
accommodate various paper sizes but are however noisy. 
Non-impact printers 
These are quieter printers and examples include LaserJet and inkjet printers. The Laser 
printers are a more popular choice for business use. They use a printing technique 
similar to that used in a photocopying machine. A laser beam is used to form an 
image onto the paper using toner. The print quality is high. Lasers are fast, and quiet. 
They print graphics but are more expensive. 
The ink-jet printers are mainly colour printers which mix ink depending on the image 
colour and spray it onto the paper. The toner has the 4 basic colours. They are slow, 
expensive and have a high print quality. 
What is the difference between impact and non-impact printers? 
Impact Non impact 
Makes noise when printing Quiet printers 
Print head makes contact with the paper No contact creates an image without 
striking a ribbon against the 
paper.Creates images on a surface 
without contacting it. 
Strike ribbon against the paper Use a laser beam which form an 
image onto paper using toner 
Slow printer Fast printers 
Use ribbons or ink Use toner 
Has too many moving parts hence 
unreliable 
Has fewer moving parts hence they 
are reliable. 
Impact printers are relatively inexpensive, 
and the cost of printing is also low 
because ink ribbons are inexpensive. 
Very expensive computers 
Give two advantages of non-impact printers over impact printers.
COMPUTER OPERATIONS  PACKAGES 
 Have high print quality 
 They are fast and do not make noise 
 They are reliable because they have less moving parts 
 See above [non impact section] 
Give three examples of impact printers three examples of non-impact printers. 
Impact printers Non impact printers 
Dot matrix Laser 
Daisy wheel printers Inkjet 
Line printers LED 
Chain printers Thermal 
Magnetic 
Electrostatic 
Xerographic 
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NON-IMPACT PRINTERS 
1 - Laser printers: 
How it works: • These print individual pages and work in a similar 
way to photocopiers. 
• A drum is charged to match the image and 
powdered ink (toner) sticks to the surface. The 
toner is then transferred to the paper and fixed 
by heat and pressure. 
• A school or business printer would have a typical 
speed of 10 to 20 pages per minute (ppm). 
Suitable uses: • Common wherever fast, high quality printing is required. 
Disadvantages: • Non-colour laser printers are more expensive than ink-jet printers (but the 
difference is narrowing). 
• Colour laser printers are considerably more expensive. (but their speed 
and high quality output means they are becoming more popular). 
Advantages: • They are quiet and fast and produce high quality printouts. 
• Running cost are low because although toner cartridges are expensive to 
replace, they last a long time. 
Laser printer - A type of printer that utilizes a laser beam to produce an image on a drum. 
The light of the laser alters the electrical charge on the drum wherever it hits. The drum is 
then rolled through a reservoir of toner, which is picked up by the charged portions of the 
drum. Finally, the toner is transferred to the paper through a combination of heat and 
pressure. 
Advantages 
-Monochrome or four color 
-High-quality print 
-Capable of printing an almost unlimited variety of fonts 
-Quiet operation 
Disadvantages 
-Color laser printerstend to be about five to ten times as expensive as 
monochrome 
-Cannot print on multiple-copy paper
COMPUTER OPERATIONS  PACKAGES 
2 - Ink-jet printers: 
How it works: • The print head contains tiny nozzles through 
which different coloured inks can be 
sprayed onto the paper to form the 
characters or the graphic images. 
• The ink is forced out by heat or by tiny 
piezoelectric crystals which change shape 
when an electric current is applied across 
them. 
Suitable uses: • A popular choice for home use where small amounts of printing are done 
and photographic quality colour printing is needed. 
Disadvantages: • The ink cartridges can be expensive so running costs can be high. 
• The printing speed is slow compared to a laser printer. 
Advantages: • These printers are relatively inexpensive and produce high quality black 
and white or photographic quality borderless colour printing. 
Ink-jet printer - A type of printer that works by spraying ionized ink at a sheet of paper. 
Magnetized plates in the ink's path direct the ink onto the paper in the desired shapes. Ink-jet 
printersare capable of producing high quality print approaching that produced by 
laser printers 
Advantages 
-Inexpensive way to print full-color document 
-Easily portable due to smaller mechanical parts than laser printers 
-Quiet operation 
Disadvantages 
-Slow output 
-Require a special type of ink that is apt to smudge on inexpensive copier paper 
-Cannot print on multiple-copy paper 
3. Thermal transfer printers- A type of printer that applies heat to a ribbon and the image or 
barcode is then transferred to labels or tags. This technology produces a higher quality, longer 
lasting image on the tag or label. 
Advantages 
-1 to 2 years media shelf life 
-Media is not heat sensitive 
-Medium to high image quality 
-Wide range of available types 
-Recommended for industrial use 
Disadvantages 
-Special ribbons required 
-Average operational cost 
-Cannot print on multiple-copy paper 
-Single-pass ribbons only 
4. Direct thermal printers - A type of printer that applies heat directly to specially treated paper, 
labels or tags to form the image or barcode. 
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Advantages 
-No ribbon required 
-Low operational cost 
Disadvantages
COMPUTER OPERATIONS  PACKAGES 
-Short media shelf life 
-Very heat sensitive media 
-Limited image quality 
-Limited number of available types 
-Not recommended for use in industrial, outdoor, or harsh environments 
-Cannot print on multiple 
IMPACT PRINTERS 
multiple-copy paper 
1 - Dot matrix printers: 
How it works: The print head travels 
from side to side 
across the paper and 
is made up of 
numerous pins which 
are pushed out to 
form the shape of 
each character 
The pins hit an ink ribbon against the paper so 
the characters are 
printed out. 
The paper is usually continuous with holes 
down each side and perforations so the 
pages can be easily separated by tearing. 
Because the pins make an impact against the 
paper the characters can be printed through 
several layers of self 
self-carbonating paper to 
produce duplicate copies. 
Suitable uses: • Limited to situations where duplicate copies are needed and the quality is 
not too important. 
• Typical uses might be in 
warehouses where duplicate copies of orders 
need to produced quickly and cheaply. 
Disadvantages: • The printing 
quality is low - these printers produce low to medium quality 
black and white printing and can only print low resolution graphics. 
• Because of the impact of the pins against the paper, these printers can be 
quite noisy 
noisy. 
Advantages: • The purchase cost is low 
• They can print 
fairly quickly, particularly if you remember that multiple 
copies are being pri 
printed in one print run. 
robust and can operate in harsh environments. 
• They are 
• If several sheets of self 
and the running costs are very low. 
self-carbonating paper are placed into the printer then 
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22 
,
COMPUTER OPERATIONS  PACKAGES 
the impact will produce duplicate copies. 
Dot-matrix printer- A type of printer that produces characters and illustrations by striking 
pins against an ink ribbon to print closely spaced dots in the appropriate shape. 
Advantages 
-Can print to multi-page forms- 
-Moderately priced 
-Multi-pass ribbons (saves money) 
Disadvantages 
-Noisy operation 
-Low-quality output 
-Slow print speed 
-Multi-pass ribbons (decrease in quality with each pass) 
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2. Daisy wheel Printers 
• Round disk found on older computer printers t hat extends a portion of the wheel making 
contact with ink ribbon that makes contact with paper creating the character. This 
procedure is repeated for each key pressed. 
• Daisy Wheel printer - A printer that uses a wheel with all the characters on it to produce 
output. The wheel spins to the desired characterand makes an imprint, then spins to go to 
the next character. It sounds like a little machine gun. 
• These printersgenerally aren't used much anymore due to the decreased cost of other 
printers that can produce graphics as well as text. The one good thing about a daisy-wheel 
printer is that the text is generally very crisp, but even that advantage is nullified 
now with laser printers that can produce very crisp characters as well. 
Advantages 
-Best print quality of impact printers 
Disadvantages 
-Very slow 
-Only one font can be used at a time because you must change out the Daisy 
Wheel to change fonts. 
-Cannot print graphics 
3. Chain and band printers - Uses characters on a band or chain that is moved into place 
before striking the characters onto the paper. 
Advantages 
Very fast 
Disadvantages 
-Very loud 
-Very expensive 
You have been delegated the task of selecting a new printer from a range of different options 
currently on the market. The machine has to serve a small network of microcomputers in your 
office. Software used includes a word processing package, database, spreadsheet, and 
presentation packages. Assuming that cost is not a major constraint, list 10 features of the printers, 
which you would investigate in your evaluation. 
1. Print quality, for example the print from dot matrix printers varies with the number of pins 
and even the best are inferior to laser printers. 
2. Character formation, whether made from dots as in matrix printer, or full characters as with 
daisywheel or laser printer 
3. Multi-part, i.e. whether several copies can be printed at once, as with an impact printer. 
4. Fonts or type style; early computer users were satisfied with any quality whatsoever, but the 
advances into areas such as word processing and desk top publishing have stimulated a 
demand for varying type faces or fonts within the same document
COMPUTER OPERATIONS  PACKAGES 
5. Letter quality, whether the quality is equivalent or superior to that of a good typewriter and 
so acceptable for the word processing of mail. Some printers have a choice of two print 
modes, draft quality and letter quality. 
6. Speed, in terms of characters per second. 
7. Graphics capabilities. 
8. Flexibility, for example is it suitable for one task only, such as good letter quality but not 
graphics, as with daisywheel printers, or good graphics but slow speed and indifferent 
letter quality, as with some dot matrix printers. 
9. Sheet feeding, in terms of single sheets, friction feed or sprocket feed. 
10. Capital cost or what it costs to buy. 
11. Running cost or what it costs in ribbons, print toner, special stationery  maintenance. 
12. Compatibility with standard packages; many programs support a range of printers by 
generating the correct control characters for fonts, features like italics and underline, and 
for graphics. 
13. Robustness; some very cheap printers are ideal at home but would not last very long in an 
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office. 
14. Reputation of the manufacturer as a supplier of printers. 
STORAGE DEVICES 
These are devices that store information permanently. They are also known as Auxiliary 
storage devices or Secondary storage devices. They include:- 
a) THE HARD DISK 
A fixed device for storing information within the computer system unit. The disk is not 
moveable and is also referred to as the C: drive. The amount of disk space a computer 
has determines the power of a computer. It provides fast access known as Random 
access and has high-speed storage. 
b) FLOPPY DISKETTE 
An external form of storage used for back up. Information can be deleted and rewritten 
and re-saved. The storage device is common for microcomputers. The disks are either High 
density or double density disks because data is stored more densely/ compactly than on 
regular density disks. Common size of disk is 31/2inches. 
ADVANTAGES OF FLOPPY DISKETTES 
1. They are cheaper than Hard disks and CD-ROMS 
2. They are portable hence used to transfer data or information from one computer to 
another 
3. They offer direct access and they are faster than magnetic tapes 
DISADVANTAGES OF FLOPPY DISKETTES 
1. They are prone to viruses 
2. They are difficult to handle 
3. They can easily be corrupted 
4. They have a relatively short life span 
5. They hold relatively small amounts of data 
6. They are not always 100% reliable 
CARE AND HANDLING OF A FLOPPY DISKETTE 
1. Don’t put the diskette near any magnetic field. 
2. Don’t put the diskette near any electronic motor. 
3. Don’t expose the diskette to direct sunshine or heat. 
4. Store the diskette in a cool dry dust-free environment. 
5. Don’t spill liquid onto the diskette. 
6. Don’t use any diskette which has had liquids spilled on it. 
7. Don’t bend or fold a diskette. 
8. Don’t staple labels onto the diskette.
COMPUTER OPERATIONS  PACKAGES 
9. Use a soft pencil or felt-tip pen when writing on diskette labels, as the pressure of a 
ballpoint may leave indentations on the magnetic surface. 
10. Don’t touch the magnetic surface (the black plastic like plate) of the disk, as your 
fingerprints may hinder the drive in reading from and writing to the disk . 
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c) CATRIDGE TAPE 
Data is recorded in the form of magnetized spots on an iron oxide coating of a plastic 
tape. Gaps are used to separate individual data records. The tape is similar to audiotapes. 
Access of information from the tape is in sequential form and thus slow. 
d) CD-ROM (Compact Disk Read Only Memory) 
Beams of laser light are used to write on optical disks by magnetic means. After writing, the 
disk can only be read from and not written to. Access to information is direct and very fast. 
e) WORM (Write Once, Read Many) 
WORM Disks allow microcomputers with the proper drive known as a CD Rewriters (or a 
burner) to record own data on a blank CD. Once the recording is done, the disk can only 
be read from and cannot be rewritten. 
Erasable optical disks are also available and are known as EPROM. The major advantage 
of optical disks is their storage capacity. The information on one optical requires multiple 
floppies. 
f) DVD (Digital Versatile Disks) 
A form of optical disks similar to CD ROMS but has much more storage 
capacities of up to 3.9GB. They support audio and video as well as 
data on the same disk. 
g) ZIP DISKS 
These are high capacity removable diskettes. They have gained favor for back-up 
purposes. Some zip disks use magnetic technology and others use laser. They have a 
capacity of about 100MB. 
Storage devices differ in terms of capacity, cost and access methods. For any device to 
be used there is a need for the device drive on the computer e.g. A floppy disk drive. 
DISK CARE 
1) Do not expose them to sun or a hot environment. 
2) Keep them away from moisture or water. 
3) Keep them away from magnetic fields i.e. Phones, tops of some monitors, magnetized 
items etc.. 
4) Do not touch the actual tape. 
5) Keep them away from dust. 
6) Do not place heavy objects on them. 
7) Write on a floppy disk label only with a felt-tip pen, or write before sticking the label 
8) Avoid using rubber bands, paper clips and erasers on floppy disks 
HARDWARE CARE 
1) Make sure there is enough space for the machines to breathe. (Fresh air is necessary 
to make the fan keep the electronics cool). 
2) Do not block air vents with books. 
3) Keep the computer dry. 
4) House the machine in a dust free environment e.g. 1ST floor carpeted-room (Carpets 
suck dust) and, use a vacuum cleaner to clean the carpet. (Dust is the biggest killer of 
hard drives). 
5) Do not expose the machine to extreme temperatures. 
6) Properly shut down the machine before turn-off. 
7) Pull the plug out of socket when there is thunder and lightning.
COMPUTER OPERATIONS  PACKAGES 
8) Do not move the system when the computer is on. The hard drive can be damaged. 
9) Use of UPS- Uninterruptible Power Supply in case of power failures, 
10) Use of Surge Protectors against too high voltages. 
DEFINE HARDWARE  GIVE EXAMPLES. 
 Hardware comprises all of the physical parts of a computer, as distinguished from the data 
it contains or operates on, and the software that provides instructions for the hardware to 
accomplish tasks. 
DEFINE SOFTWARE  GIVE EXAMPLES. 
 Computer software (or simply software) refers to one or more computer programs and 
data held in the storage of a computer for some purpose. 
 Program software performs the function of the program it implements, either by directly 
providing instructions to the computer hardware or by serving as input to another piece of 
software. 
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CLASSIFICATION OF COMPUTERS 
Computers differ based on their data processing abilities. They are classified according to purpose, 
data handling and functionality. 
• According to purpose, computers are either general purpose or specific purpose. 
 General purpose computers are designed to perform a range of tasks. They have 
the ability to store numerous programs, but lack in speed and efficiency. 
 Specific purpose computers are designed to handle a specific problem or to 
perform a specific task. A set of instructions is built into the machine. 
• According to data handling, computers are analog, digital or hybrid. 
 ANALOG COMPUTERSwork on the principle of measuring, in which the 
measurements obtained are translated into data. Modern analog computers 
usually employ electrical parameters, such as voltages, resistances or currents, to 
represent the quantities being manipulated. Such computers do not deal directly 
with the numbers. They measure continuous physical magnitudes. 
 DIGITAL COMPUTERSare those that operate with information, numerical or 
otherwise, represented in a digital form. Such computers process data into a 
digital value (in 0s and 1s). They give the results with more accuracy and at a 
faster rate. Hybrid computers incorporate the measuring feature of an analog 
computer and counting feature of a digital computer. For computational 
purposes, these computers use analog components and for storage, digital 
memories are used. 
• According to functionality, computers are classified as : 
 Analog Computer 
An analog computeris a form of computer that uses continuous physical 
phenomena such as electrical, mechanical, or hydraulic quantities to model the 
problem being solved 
 Digital Computer 
A computer that performs calculations and logical operations with quantities 
represented as digits, usually in the binary number system
COMPUTER OPERATIONS  PACKAGES 
 Hybrid Computer (Analog + Digital) 
A combination of computers those are capable of inputting and outputting in 
both digital and analog signals. A hybrid computer system setup offers a cost 
effective method of performing complex simulations. 
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Classification on the basis of Size 
Major classes or categories of computers 
Supercomputers 
 Describes a category of extremely powerful computers specifically designed for high-speed 
numeric computation. 
 The computers can process hundreds of millions of instructions per second. 
 High capacity computers capable of executing instructions faster than main frame  are 
extremely expensive. 
 The speed of executing these instructions generates extreme heat, and therefore the 
computers require special cooling system to operate. 
 Uses include weather forecasting, scientific and mathematical research, and design of high-speed 
aircraft and space exploration. 
Mainframes 
 Are large, powerful computers that are physically larger than micros and minis and usually 
have one or more central processors with faster instruction processing speeds? 
 They typically process hundreds of millions of instructions per second. 
 Mainframes have large primary storage capacities. 
 Many mainframe models have the ability to service hundreds of users at once. 
 Some commercial organizations require large amounts of data to be processed in the list 
possible time. 
 Mainframes allow one to perform such functions 
 Uses of mainframes include: data warehousing, commercial airline ticketing  reservations, 
government record keeping  financial servicing 
 Application categories: Host computers, Database servers, and Transaction processors. 
Minicomputers 
 Are larger and more powerful than most microcomputers but are smaller and less powerful 
than most mainframe computer systems. 
 Serve in industrial process-control manufacturing plant computers and play a major role in 
CAM. 
 Also take the form of powerful technical workstations for CAD applications. 
 Often used as front-end processors/computers to help mainframe computers control data 
communications networks with large numbers of data entry terminals. 
 Also used as powerful Network servers to help manage large interconnected LANs that tie 
together many workstations 
 Downsizing is a term that was commonly used in the early nineties when smaller computers, 
capable of much of the functions of mainframes, began capturing the computer market. 
 Minicomputers are suitable for mid-sized companies that require the computing power of 
mainframes to be efficient and at the same time be cost effective. 
 Users of mini-computers would be smaller banks  financial institutions, supermarket chains and 
departmental stores. 
 Application categories: Network servers, and Application systems 
Microcomputers 
 We refer to a microcomputer as a personal computer or PC. 
 Microcomputers categorized by size include: Desktops, Laptops for example. 
 Most microcomputers are single user computers. 
 The late nineties have seen a huge influx of microcomputers whose sole aim was to provide 
affordable computing power to the general public.
COMPUTER OPERATIONS  PACKAGES 
 They are now used as Network servers. The demand for microcomputers and the changes in 
microchip technology have produced cheaper computers that are affordable to students 
and the general public. 
 Can support CAD. 
 Users of microcomputers range from students, who use them for word processing, to a 
salesperson. Who depend on the microcomputer for information? 
 Application categories: PCs, Network servers. 
 Network servers are powerful microcomputers that controls  coordinates communication  
resource sharing in LANs of interconnected PCs  other devices. 
The main differences among the above computer types are in: 
• Processing speed, 
• Memory capacity 
• Number and capabilities or peripheral devices that can be attached to the computer 
• Usage. 
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COMPUTER APPLICATIONS 
a) Business- for administration, payroll and accounting. 
b) Government- keeping database records. 
c) Education- Record keeping, accounting and training in the classroom. 
d) Health- Record keeping, life-support systems. 
e) Sport- fitness monitoring. 
f) Art and Design- desktop Publishing, technical graphics, Computer Aided Design. 
g) Homes- PCs for home accounts, games, e-mail, online shopping, home education 
etc. 
h) Banks- Record keeping and updating, on-line Automated Teller Machines (ATMs). 
i) Supermarkets- Electronic point Of Sale Machines (EPOS) – tills. 
FACTORS TO CONSIDER WHEN YOU WANT TO PURCHASE OR BUYA COMPUTER 
1. COST; how much can I afford to pay for a computer? Prices of personal computers 
range from a few hundred to thousands of dollars. Faster and more feature-rich PCs 
are usually more expensive. 
2. AREA OF USE; where will my new PC be used? If you will be using it only in your home or 
office, a desktop computer will be suitable. However, if you will need to take it with 
you, you should consider purchasing a laptop (notebook) computer. 
3. APPLICATIONS PACKAGES; Which application packages will I run on my computer? 
Make a list of applications for which you plan to use your PC. For example, will you use 
your PC to prepare letters and reports? Analyze numeric and financial data? Prepare 
visual presentations? Access the Internet? Listen to music? Create and work with 
graphics? 
4. DURATION; How long will I keep this computer?Try to estimate the length of time 
(years) you will use your computerbefore BUYING the next one. If you expect use your 
PC for several years or if you think you may later want to add new applications, 
CONSIDER one that is expandable, so you can add new components, such as a 
modem, printer, or add-on boards. Make sure the PC has expansion slots so you can 
connect these devices to your PC. 
5. MANUFACTURER AND SELLER REPUTATION. Check out the manufacturers and seller’s 
reputations.Talk with friends, co-workers, classmates, teachers, and others about their 
PCs. Ask about the performance of their PCs and get recommendations from persons 
you trust. Eventually you may need to have your PC serviced. Ideally, the vendor has a 
service department that can repair your PC. If not, you may need to locate a third-party 
to provide this service. Reputable computer manufactures include:
COMPUTER OPERATIONS  PACKAGES 
1. Hewlett-Packard 2. Apple 3. Sun Microsystems 4. Dell 5. Panasonic 6.Sony 7.Toshiba 
8. Shuttle 9. IBM 10. Samsung Electronics 11. Hitachi 12. Fujitsu Siemens 
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6. WARRANTIES  GUARANTEES 
7. PC ARCHITECTURE. PC architecture refers to the design and construction of the PC and 
its system unit, and not all architectures are the same. For example, the architecture of 
an Apple Macintosh differs from that of an IBM or compatible PC. Therefore, software 
written for an Apple Macintosh PC may not run on an IBM or IBM-compatible PC. 
Although some users prefer a Macintosh PC, more software is available for IBM and 
IBM-compatible PCs. 
8. MICROPROCESSOR SPEED. Selecting the right microprocessor is extremely important. 
Processing speed, measured in megahertz (MHz) or gigahertz (GHz), is probably the 
first consideration. The higher the number of MHz or GHz, the faster the processor will 
manipulate data. If speed is important, consider choosing a microprocessor with a 
speed of 2 GHz or more. PCs containing microprocessors with speeds up to 10 GHz 
and higher are available. 
9. MAIN MEMORY (RAM). Main memory (RAM) is needed for the temporary storage of 
programs and data while the data is being processed. Some application software 
requires a considerable amount of RAM to function properly, and newer software 
versions usually require more RAM than older versions. Typical PCs now come with 2 
gigabytes (GB), 5GB, or more of RAM. Make certain the PC has sufficient RAM to run 
the software you will be using. 
10. SECONDARY STORAGE (ROM). What type(s) and amounts of secondary storage are 
you likely to need? Typical computers come with a floppy disk drive, cd drive, USB 
port/ drive and a hard disk drive already installed. A hard disk drive contains one or 
more rigid storage platters and provides for the permanent storage of considerably 
more data. However, the disk itself cannot be removed from the drive. 
The STORAGE CAPACITY of a hard disk is an important consideration because it is used 
to store all system and application software. Typical hard disk capacities are 100, 200, 
500GB or 2TB and more. Be certain the PC you are considering has sufficient 
secondary capacity for your needs 
CD-ROM or DVD drives provide high storage capacities. Most software publishers store 
their programs on CD-ROM or DVDs because of the high capacity and because 
DVD/CD-ROMs operate faster than floppy disks. 
If you will use your PC to play movies, your purchase should include a DVD (digital 
video disk) drive. If you will work with large files, consider purchasing a computer that 
includes a DVD/CD-RW drive. A DVD/CD-RW disk is a reusable high-capacity disk that 
allows you to store huge amounts of data and to erase data no longer needed. 
11. PORTS.The number of ports (slots) available inside the system unit determines the 
number of add-on boards that can be installed inside the system unit. For example, 
you cannot connect a printer to your computer unless youcomputerr is equipped with 
an appropriate port (slot). Be sure the PC contains the necessary slots for the add-on 
boards and peripheral devices you will be using with your computer. 
12. INPUT DEVICES.Typical input devices are a keyboard and a mouse, although other 
kinds of input devices are available. Most keyboards and mice operate similarly. 
However, there are slight differences in how each feels to the user. Before buying a 
PC, you may want to test the keyboard and mouse for comfort and ease of use. Some 
sellers will allow you to exchange the keyboard or mouse that comes with the 
computerfor a different one.
COMPUTER OPERATIONS  PACKAGES 
13. OUTPUT DEVICES. Output devices produce output in either soft copy or hard copy 
form. Most PCs come with a monitor (for soft copy output), but you may have to 
purchase a hard copy device, such as a printer, separately. 
14. MONITORS. There are wide differences among PC monitors, with resolution being 
perhaps the most important variable. 
Resolution refers to the clarity of the text and images being displayed. Before making 
a purchase, carefully evaluate the monitor’s resolution. Many vendors allow you to 
choose from monitors with varying resolutions. A resolution of 1,024 by 1,024 is 
considered high-resolution, in which text and images display exceptionally clearly. 
High-resolution monitors are typically more expensive. 
Monitor size is another important consideration. Viewing areas range from 15 diagonal 
inches to 21 inches and higher. Larger monitors are usually more expensive, but may 
be worth the extra cost. For example, an individual with weak vision may prefer a 
larger monitor. If your desktop space is limited, consider purchasing a flat-panel 
monitor, which occupies less space. Flat-panels are more expensive than standard 
monitors, however. 
NECESSARY CONDITIONS FOR AN IDEAL COMPUTER ROOM ENVIRONMENT. 
1. Cleanliness [books, manuals not encouraged] because they bring dust  caught fire 
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easily. 
2. Air conditioners, which control the room and dehumidates it. 
3. It should be dust free; dust is the biggest “killer” of hard drives. 
4. No carpets, they caught fire more easily. 
5. You are not allowed to eat, smoke or drink in the computer room. 
6. No magnetic material should be in the computer room. 
7. The computer room should be located in such a way that computers are not 
exposed to direct sunlight or hot environments, use curtains if otherwise. 
8. The computer room should be fitted with burglar bars, alarm systems, or guarded 
24hours to ensure security. 
9. The computer room should have surge protectors or suppressors to guard against 
electrical faults and high voltages. 
10. The computer room should have UPS [uninterrupted power supply] in case of power 
failures, which may be fatal. 
11. Computer room should be well ventilated, to allow for air circulation, 
12. Foreign media, such as floppy diskettes, flash disks should not be allowed in order to 
minimize virus spread. 
13. Always switch off machines if not in use. 
14. Avoid overloading circuits. 
15. All cabling and wiring should not be exposed; it should be covered and should not 
criss cross the room. 
16. Leave enough space between computers and the walls. 
17. Do not use chalk the computer room , dry wipe markers are encouraged.
COMPUTER OPERATIONS  PACKAGES 
DUTIES  RESPONSIBILITIES OF COMPUTER PERSONNEL 
ROLES OF A Database Administrator (DBA) 
a) The design of the database 
b) After the initial design, the DBA must monitor the performance of the database, and if 
problems surface (such as a particular report taking an unacceptably long time to 
produce), appropriate changes must be made to the database structure. 
c) Keeping users informed of changes in the database structure that will affect them; for 
example, if the size or format of a particular field is altered or additional fields added 
d) Maintenance of the data dictionary for the database, and responsibility for 
establishing conventions for naming tables, columns, indexes 7 so on. 
e) Implementing access privileges for all users of the database; that is, specifying which 
items can be accessed and / or changed by each user. 
f) Allocating passwords to each user. 
g) Providing training to users in how to access and use the database. 
h) Manage the organization of 
i. -data resources 
ii. -database plans 
iii. -design 
iv. -operations 
v. -training 
vi. -user support 
vii. -security  Maintenance 
i) Maintain data consistency and security 
j) Approve access to data stored 
k) Approve access procedures 
l) ABILITY to delete, add, modify –existing data must be tightly controlled. 
1. COMPUTER SUPPORT SPECIALISTSprovide technical assistance, support, and advice to 
customers and other users. This occupational group includes technical support 
specialists and help-desk technicians. These troubleshooters interpret problems and 
provide technical support for hardware, software, and SYSTEMS. They answer 
telephone calls, analyze problems by using automated diagnostic programs, and 
resolve recurring difficulties. Support specialists may work either within a company 
that uses computer SYSTEMSor directly for a computer hardware or software vendor. 
Increasingly, these specialists work for help-desk or support services firms, for which 
they provide computer support to clients on a contract basis. 
2. TECHNICAL SUPPORT SPECIALISTSanswer telephone calls from their organizations’ 
computer users and may run automatic diagnostics programs to resolve problems. 
Working on monitors, keyboards, printers, and mice, they install, modify, clean, and 
repair computer hardware and software. They also may write training manuals and 
train computer users in how to use new computer hardware and software. In 
addition, technical support specialists oversee the daily performance of their 
company’s computer SYSTEMSand evaluate software programs with regard to their 
usefulness. 
3. HELP-DESK TECHNICIANSassist computer users with the inevitable hardware and 
software questions that are not addressed in a product’s instruction manual. Help-desk 
technicians field telephone calls and e-mail messages from customers who are 
seeking guidance on technical problems. In responding to these requests for 
guidance, help-desk technicians must listen carefully to the customer, ask questions 
to diagnose the nature of the problem, and then patiently walk the customer through 
the problem-solving steps.Help-desk technicians deal directly with customer issues, 
and companies value them as a source of feedback on their products. These 
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COMPUTER OPERATIONS  PACKAGES 
technicians are consulted for information about what gives customers the most 
trouble, as well as other customer concerns. Most computer support specialists start 
out at the help desk. 
4. NETWORKADMINISTRATORS AND COMPUTERSYSTEMS ADMINISTRATORSdesign, install, 
and support an organization’s local-area network (LAN), wide-area network (WAN), 
network segment, Internet, or intranet system. They provide day-to-day onsite 
administrative support for software users in a variety of work environments, including 
professional offices, small businesses, government, and large corporations. They 
maintain network hardware and software, analyze problems, and monitor the 
network to ensure its availability to system users. These workers gather data to identify 
customer needs and then use the information to identify, interpret, and evaluate 
system and network requirements. Administrators also may plan, coordinate, and 
implement network security measures. 
5. SYSTEMSADMINISTRATORSare the information technology employees responsible for 
the efficient use of networks by organizations. They ensure that the design of an 
organization’s computer site allows all of the components, including computers, the 
network, and software, to fit together and work properly. Furthermore, they monitor 
and adjust the performance of existing networks and continually survey the current 
computer site to determine future network needs. Administrators also troubleshoot 
problems reported by users and by automated network monitoring SYSTEMSand 
make recommendations for enhancements in the implementation of future servers 
and networks. 
6. In some organizations, COMPUTER SECURITY SPECIALISTSmay plan, coordinate, and 
implement the organization’s information security. These workers may be called upon 
to educate users about computer security, install security software, monitor the 
network for security breaches, respond to cyber attacks, and, in some cases, gather 
data and evidence to be used in prosecuting cyber crime. The responsibilities of 
computer security specialists has increased in recent years as there has been a large 
increase in the number of cyber attacks on data and networks. This and other 
growing specialty occupations reflect an increasing emphasis on client-server 
applications, the expansion of Internet and intranet applications, and the demand 
for more end-user support. 
7. COMPUTER PROGRAMMERSwrite, test, and maintain the detailed instructions, called 
programs that computers must follow to perform their functions. Programmers also 
conceive, design, and test logical structures for solving problems by COMPUTER. 
Programmers write programs according to the specifications determined primarily by 
COMPUTER software engineers and systems analysts.After the design process is 
complete, it is the job of the Programmer to convert that design into a logical series of 
instructions that the COMPUTER can follow. The Programmer codesthese instructions 
in a conventional programming language such as COBOL; an artificial intelligence 
language such as Prolog; or one of the most advanced object-oriented languages, 
such as Java, C++, or ACTOR. Different programming languages are used depending 
on the purpose of the program. 
8. DATA PREPARATION STAFF 
Are those people responsible for the translation of data into machine readable form. 
9. COMPUTER SCIENTISTSwork as theorists, researchers, or inventors. Their jobs are 
distinguished by the higher level of theoretical expertise and innovation they apply to 
complex problems and the creation or application of new technology. Those 
employed by academic institutions work in areas ranging from complexity theory to 
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COMPUTER OPERATIONS  PACKAGES 
hardware to programming-language design. Some work on multidisciplinary projects, 
such as developing and advancing uses of virtual reality, extending human-computer 
interaction, or designing robots. Their counterparts in private industry work in areas 
such as applying theory; developing specialized languages or information 
technologies; or designing programming tools, knowledge-based systems, or even 
computer games. 
10. DATA ENTRY AND INFORMATIONPROCESSING WORKERShelp ensure the smooth and 
efficient handling of information. By keying in text, entering data into a computer, 
operating a variety of office machines, and performing other clerical duties, these 
workers help organizations keep up with the rapid changes that are characteristic of 
today’s “Information Age.” In addition to the job titles discussed below—such as word 
processors, typists, and data entry keyers—data entry and information processing 
workers are known by various other titles, including electronic data processors, 
keypunch technicians, and transcribers. 
11. DATA ENTRY KEYERSusually input lists of items, numbers, or other data into computers 
or complete forms that appear on a computer screen. They also may manipulate 
existing data, edit current information, or proofread new entries into a database for 
accuracy. Some examples ofdata sources include customers’ personal information, 
medical records, and membership lists. Usually, this information is used internally by a 
company and may be reformatted before other departments or customers utilize it. 
12. DATA CONTROL is our customer services area for all agencies that utilize Information 
Technology's services for reports of any kind. This section receives and distributes all 
incoming data for appropriate processing; they set up batch reporting for all 
agencies and submit schedules for processing to Computer Operations. After 
processing has occurred, they check and distribute reports to all customers. This area 
interacts with agency customers and other Information Technology areas to resolve 
processing problems. This area maintains all tape media including updating the tape 
inventory system and it also has responsibility for off site tape storage. Updating the 
Information Technology web page using HTML and other software tools is done by 
Data control. Data control is also responsible for all data preparation prior to 
centralized processing. Assisting the paper peripheral area and reception area are 
also functions of this section. 
13. COMPUTER OPERATORSare responsible for the operation of all enterprise, Unix, NT, and 
Windows 2000 servers, Unix and personal computers that are utilized to service the 
County's customer base. This area receives all hardware service calls, assists in 
terminal and communication equipment installation and software/hardware trouble 
diagnosis. Processing of all batch production work as well as all paper peripheral 
processing are also functions of Computer Operations. 
14. NETWOR MANAGER, managing a network infrastructure and providing technical 
support and advice to the client organisations. This type of post would usually require 
the postholder to be educated to degree level or equivalent standard and to have 
considerable experience of network management and protocols including TCP/IP. 
Additional requirements might include experience in the management of industry 
standard network operating systems such as Novell NetWare, UNIX and MS Windows 
NT  2000 server, together with skills in the use of database applications, such as 
Oracle, email server applications such as MS Exchange 5.5 or 2000 and PC 
applications such as MS Office  XP. 
Research – important area 
1. FIND OUT THE DUTIES AND RESPONSIBILITIES OF THE FOLLOWING 
rmmakaha@gmail.com 33 
a) Computer programmer 
b) System analyst 
c) System administrator 
d) Computer librarian
COMPUTER OPERATIONS  PACKAGES 
rmmakaha@gmail.com 34 
e) Data preparation staff 
f) Network administrator 
g) Data control staff 
h) IT manager 
i) Data processing manager 
j) Computer operators 
k) Data capturing clerk 
2. Write notes on 
DATA PROCESSING METHODS 
a) Manual data processing 
b) Mechanical data processing 
c) Electronic data processing 
d) Automatic data processing 
e) Online data processing 
f) Distributed data processing 
g) Centralized data processing 
h) Transaction processing 
i) Decentralized data processing 
j) Time sharing data processing 
k) Batch or offline data processing 
3. Advantages and disadvantages of computers 
Ask if you are not sure 
DATA SECURITY /PROTECTION 
 Data Security/Protection 
 Refers to keeping data safe from various hazards or dangers like natural hazards, 
deliberate corruption or destruction of software  hardware by malicious or terrorist 
acts, illegal access to data by hackers [people who break into the system]  
accidental destruction of data by hardware or software failure [operator error]. 
MEASURES TO ENSURE DATA SECURITY 
1. Data Encryption/Decryption- Data is coded before transmission over a WAN  decrypted 
only if you have the key  code to decrypt the data on the receiving end. The process of 
transforming a message in ordinary language i.e. plain text to produce what is called 
cipher text which is then send along a communication line/link. The receiving computer 
uses another transformation to decode the message. 
a. Definitions of decryption on the Web: 
• The process of converting encrypted content back into its original form, often the process of 
converting cipher text to plaintext. Decryption is the opposite of encryption. 
• Definitions of encryption on the Web: 
• Any procedure used in cryptography to convert plaintext into cipher text in order to prevent 
anyone except the intended recipient from reading that data. There are many types of data 
encryption, and they are the basis of network security. Common types include Data Encryption 
Standard and public-key encryption. 
• Definitions of cipher text on the Web: 
• Data that has been transformed by encryption so that its semantic information content (ie, its 
meaning) is no longer intelligible or directly available. 
2. Firewall- a firewall is a software program designed to prevent unauthorized access to a PC or 
network through a connection to the Internet. It works by monitoring all data sent to and from the 
PC and comparing the data with a set of user-defined security criteria. Any data that does not 
meet that criteria is blocked. Firewalls also process encrypted data. They verify the validity of the 
user. User would require access to the firewall before they can transmit data. Latest firewalls also 
have the ability to detect virus software in packets of data that is sent through the network. 
Firewalls disallow data transmission if it detects strains of virus on the data being transmitted. 
3. Usernames  Passwords-Passwords restrict only authorized personnel/users to have 
access to the data or computer rooms [cards]. Passwords bring in an aspect of 
accountability, if a file is deleted, the person with the password will be reported as 
the culprit through logging. Passwords can be forgotten. Widely used by 
companies to protect their equipment  data 
4. Authorized entry to computer installations-Most installations have card readers, 
voice recognition systems or keypads on the doors that prohibit entry to 
unauthorized personnel. 
5. Backing-up files on external disks periodically. 
6. Keeping backup copies of files in a different location and making about 3 
generations of backup.
COMPUTER OPERATIONS  PACKAGES 
7. Saving work frequently 
8. Avoiding viruses. 
9. Restricting access to the computer room. Access could be only through codes, 
voice recognition etc. 
10. Installing fire alarms. 
11. Lining computer rooms with fire resistant material. 
12. Placing the computer room in upper floors of a building to avoid burglaries. 
13. Having a security guard 24 hours a day. 
Summary - Keeping data secure 
Measures that can be taken to keep data safe include: 
• Making regular back-ups of files. (Back up copies should be stored safely in fireproof safes 
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or in another building.) 
• Protecting yourself against viruses by running anti-virus software. 
• Using a system of passwords so that access to data is restricted. 
• Safe storage of important files stored on removable disks - eg locked away in a fireproof 
and waterproof safe. 
• Allowing only authorized staff into certain computer areas, eg by controlling entry to these 
areas by means of ID cards or magnetic swipe cards. 
• Always logging off or turning terminals off and if possible locking them. 
• Avoiding accidentally deletion of files by write-protecting disks. 
• Using data encryption techniques to code data so that it makes no apparent sense 
 BACK UP 
 Copying or saving data to a different location. One can restore the backup copy 
if data is lost or damaged. 
 To create a copy of a disk’s contents on another location for safe keeping. Since 
hard drives are not infallible, it is recommended that you backup its contents 
regularly. 
DISASTER PLANNING 
 Many companies have comprehensive emergency plans so that even after suffering a severe: 
 Bomb 
 Fire damage 
 Natural disaster, the company can be up and running within a day or two. 
 A disaster recovery service/programme provides for example 
 Office space 
 Computer facilities 
 Phones 
 Desks, at an emergency BACKUP site. 
 A completely up to date copy of the company Database may be permanently maintained at 
this site with all transactions being transmitted to this remote site updating the database, 
copying etc. 
 The data should be backed up/stored to one or more media to ensure recovery in case of 
disaster. 
 The back up procedures and media should be tested periodically to assess their effectiveness. 
Definitions of disaster plan on the Web: 
• The documented policies and procedures intended to either prevent damage, minimize 
damage, or recover from damage to record materials. 
Definitions of disaster recovery plan on the Web: 
• The document that defines the resources, actions, tasks and data required to manage the 
business recovery process in the event of a business interruption. The plan is designed to 
assist in restoring the business process within the stated disaster recovery goals. 
• Part of an overall contingency plan. The plan for a process whereby an enterprise would 
restore any loss of data in the event of fire, vandalism, natural disaster, or system failure.
COMPUTER OPERATIONS  PACKAGES 
MAJOR THREATS TO INFORMATION SYSTEMS/COMPUTERS 
Key threats to data security 
• Data can be lost or damaged during a system crash - especially one affecting the hard 
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disk. 
• Data can become corrupt as a result of faulty disks or disk drives, or power failures. 
• Data can be lost by accidentally deleting or overwriting files. 
• Data can be lost or become corrupted by computer viruses. 
• Data can be hacked into by unauthorized users and deleted or altered. 
• Data can be destroyed by terrorist activities, war, bombs and fire. 
• Data can be deleted or altered by unpleasant employees wishing to make money or seek 
revenge on their employers. 
Explain 5 major threats to information systems; for each threat describe its impact and 
preventative measure you would adopt to prevent it. [15]. 
THREAT IMPACT CONTROL 
Hardware failure • You are grounded 
• You cannot access the 
system 
• Data is incorrectly/ 
incompletely processed 
• Have spares in the 
warehouse. 
• Do regular servicing 
• Have a disaster plan 
• Run hardware diagnostics 
frequently 
Electrical faults • Loss of data 
• Disk crushes 
• Damage to hardware 
• Have standby generators 
• Install UPS [uninterrupted 
power supply] 
• Install Surge suppressors/ 
protectors 
Software failures • Operations are grounded 
• Buy software from 
reputable vendors. 
• Do regular back ups 
• Software diagnostics 
Natural disasters/ physical threats • Absolute destruction • Relocate backups to 
other areas free from 
disasters 
Viruses • Deletion  corruption of files 
• Reformatting of documents 
• System may fail to work 
• Install a reliable anti-virus 
software 
• Never download 
unknown e-mail 
attachments 
• Scan unknown diskettes 
Hackers, Computer crime • Security is breached 
• Security is bypassed 
• Destruction of files 
• Data is stolen 
• Change passwords 
regularly 
• Employ a security guard 
• Install a firewall 
• Prevent unauthorized 
access to computer 
facilities. 
War and Terrorist activity 
Human error
COMPUTER OPERATIONS  PACKAGES 
Definitions of computer abuse on the Web: 
• The willful or negligent unauthorized activity that affects the availability, confidentiality, or 
integrity of computer resources. Computer abuse includes fraud, embezzlement, theft, 
malicious damage, unauthorized use, denial of service, and misappropriation 
Definitions of hacking on the Web: 
• Unauthorized use, or attempts to circumvent or bypass the security mechanisms of an 
information system or network. Hacking means illegally accessing other people's computer 
systems for destroying, disrupting or carrying out illegal activities on the network or 
computer systems. 
DATA INTEGRITY/RELIABILITY 
• Refers to the correctness AND The accuracy of data after being transmitted or processed 
• Data in the computer system may become incorrect, corrupted or of poor quality in many 
different ways  at any stage during data processing. 
 Consequences of system failure: 
 Loss of business due downtime 
 Delays 
 Air traffic control system could well have catastrophic results 
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COMPUTER CRIME/FRAUD 
 Computer crimes are criminal activities, which involve the use of information technology to 
gain an illegal or an unauthorized access to a computer system with intent of damaging, 
deleting or altering computer data. Computer crimes also include the activities such as 
electronic frauds, misuse of devices, identity theft and data as well as system interference. 
Computer crimes may not necessarily involve damage to physical property. They rather 
include the manipulation of confidential data and critical information. Computer crimes 
involve activities of software theft, wherein the privacy of the users is hampered. These 
criminal activities involve the breach of human and information privacy, as also the theft 
and illegal alteration of system critical information. The different types of computer crimes 
have necessitated the introduction and use of newer and more effective security 
measures. 
 Computer Fraud/Crime 
 Criminal actions accomplished through the use of computer systems, especially 
with the intent to defraud, destroy, damage, or make unauthorized use of 
computer resources. 
 E.g. improper transfer of funds from one account to another 
TYPES OF COMPUTER CRIME/FRAUD 
a) Intellectual Crime – cracking into a computer system for the purpose of 
transferring or obtaining funds is a typical e.g. 
b) Destruction of property – destroying a computer property 
c) Theft – Software piracy which is unauthorized copying of software. Hardware  
software being taken away without the knowledge/consent of its owners. 
d) Fraud achieved by the manipulation of computer records. 
e) * Spamming wherever outlawed completely or where regulations controlling it are 
violated. 
f) * Deliberate circumvention of computersecurity systems. 
g) * Unauthorized access to or modification of programs (see software cracking and 
hacking)  data. 
h) * Intellectual property theft, including software piracy. 
i) * Industrial espionage by means of access to or theft of computer materials. 
j) * Identity theft where this is accomplished by use of fraudulent computer 
transactions. 
k) * Writing or spreading computerviruses or worms.
COMPUTER OPERATIONS  PACKAGES 
l) * Salami slicing is the practice of stealing money repeatedly in extremely small 
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quantities. 
m) *DNSDenial-of-service attack, where company websites are flooded with service 
requests and their website is overloaded and either slowed or crashes completely. 
n) * Making and digitally distributing child pornography 
Types of Computer Crime 
Hacking: The activity of breaking into a computer system to gain an unauthorized access is known 
as hacking. The act of defeating the security capabilities of a computer system in order to obtain 
an illegal access to the information stored on the computer system is called hacking. The 
unauthorized revelation of passwords with intent to gain an unauthorized access to the private 
communication of an organization of a user is one of the widely known computer crimes. Another 
highly dangerous computer crime is the hacking of IP addresses in order to transact with a false 
identity, thus remaining anonymous while carrying out the criminal activities. 
Phishing: Phishing is the act of attempting to acquire sensitive information like usernames, 
passwords and credit card details by disguising as a trustworthy source. Phishing is carried out 
through emails or by luring the users to enter personal information through fake websites. Criminals 
often use websites that have a look and feel of some popular website, which makes the users feel 
safe to enter their details there. 
Computer Viruses: Computer viruses are computer programs that can replicate themselves and 
harm the computer systems on a network without the knowledge of the system users. Viruses 
spread to other computers through network file system, through the network, Internet or by the 
means of removable devices like USB drives and CDs. Computer viruses are after all, forms of 
malicious codes written with an aim to harm a computer system and destroy information. Writing 
computer viruses is a criminal activity as virus infections can crash computer systems, thereby 
destroying great amounts of critical data. 
Cyberstalking: The use of communication technology, mainly the Internet, to torture other 
individuals is known as cyberstalking. False accusations, transmission of threats and damage to 
data and equipment fall under the class of cyberstalking activities. Cyberstalkers often target the 
users by means of chat rooms, online forums and social networking websites to gather user 
information and harass the users on the basis of the information gathered. Obscene emails, 
abusive phone calls and other such serious effects of cyberstalking have made it a type of 
computer crime. 
Identity Theft: This is one of the most serious frauds as it involves stealing money and obtaining other 
benefits through the use of a false identity. It is the act of pretending to be someone else by using 
someone else's identity as one's own. Financial identity theft involves the use of a false identity to 
obtain goods and services and a commercial identity theft is the using of someone else’s business 
name or credit card details for commercial purposes. Identity cloning is the use of another user's 
information to pose as a false user. Illegal migration, terrorism and blackmail are often made 
possible by means of identity theft. 
The different types of computer crimes involve an illegal exploitation of the computer and 
communication technology for criminal activities. While the advancing technology has served as a 
boon to mankind, the destructively directed human intellects are all set to turn technology into a 
curse. However, crimes are sure to end, as it is truth that always triumphs! 
1. Intellectual crime – cracking into a computer system with the sole aim of transferring or 
stealing funds, e.g. Salami slicing which is the activity of obtaining or stealing money 
repeatedly in extremely small quantities over a period of time 
2. Destruction of property 
3. Software piracy
COMPUTER OPERATIONS  PACKAGES 
4. Deliberate circumvention of computer security systems or unauthorized access to or 
modification of computer programs and data; i.e. hacking which attempts to bypass the 
security mechanism of a computer system or network 
5. Theft of computer hardware and software or taking away software without the owner’s 
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consent 
6. Making and distributing pornography 
MEASURES TO COUNTER OR COMBAT COMPUTER CRIME [COMPUTER SECURITY] 
 Careful vetting of employees 
 Separation of duties 
 Use of passwords 
 Security manager software-to monitor attempts to access the system whether 
successful or not. 
 Educating staff 
 Prevention of unauthorized access to the computer operations room 
 Data Encryption/Decryption 
1. Establish strong passwords 
Implementing strong passwords is the easiest thing you can do to strengthen your security. 
Cloutier shares his tip for crafting a hard-to-crack password: use a combination of capital 
and lower-case letters, numbers and symbols and make it 8 to 12 characters long. 
You should definitely avoid using: any personal data (such as your birthdate), common 
words spelled backwards and sequences of characters or numbers, or those that are close 
together on the keyboard. 
Use their convenient password checker to see how strong yours is. 
As for how often you should change your password, Cloutier says that the industry 
standard is every 90 days, but don't hesitate to do it more frequently if your data is highly-sensitive. 
Another key: make sure every individual has their own username and password for any 
login system, from desktops to your CMS. Never just use one shared password, says 
Cloutier. 
And finally, Never write it down! he adds. 
2. Put up a strong firewall 
In order to have a properly protected network, firewalls are a must, Cloutier says. 
A firewall protects your network by controlling internet traffic coming into and flowing out 
of your business. They're pretty standard across the board -- Cloutier recommends any of 
the major brands. 
3. Install antivirus protection 
Antivirus and anti-malware software are essentials in your arsenal of online security 
weapons, as well. 
They're the last line of defense should an unwanted attack get through to your network, 
Cloutier explains. 
4. Update your programs regularly 
Making sure your computer is properly patched and updated is a necessary step towards 
being fully protected; there's little point in installing all this great software if you're not going 
to maintain it right. 
Your security applications are only as good as their most recent update, Watchinski 
explains. While applications are not 100 percent fool-proof, it is important to regularly 
update these tools to help keep your users safe.
COMPUTER OPERATIONS  PACKAGES 
Frequently updating your programs keeps you up-to-date on any recent issues or holes 
that programmers have fixed. 
rmmakaha@gmail.com 40 
5. Secure your laptops 
Because of their portable nature, laptops are at a higher risk of being lost or stolen than 
average company desktops. It's important to take some extra steps to make certain your 
sensitive data is protected. 
Encryption software changes the way information looks on the harddrive so that, without 
the correct password, it can't be read. 
6. Secure your mobile phones 
Cloutier points out that smartphones hold so much data these days that you should 
consider them almost as valuable as company computers -- and they're much more easily 
lost or stolen. As such, securing them is another must. 
The must-haves for mobile phones: 
• Encryption software 
• Password-protection (Cloutier also suggests enabling a specific lock-out period, 
wherein after a short amount of time not being used, the phone locks itself) 
• Remote wiping enabled 
7. Backup regularly 
Scheduling regular backups to an external hard drive, or in the cloud, is a painless way to 
ensure that all your data is stored safely. 
The general rule of thumb for backups: servers should have a complete backup weekly, 
and incremental backups every night; personal computers should also be backed up 
completely every week, but you can do incremental backups every few days if you like 
(however long you could live without your data, Cloutier explains). 
Getting your data compromised is a painful experience -- having it all backed up so you 
don't completely lose it will make it much less so. 
8. Be careful with e-mail, IM and surfing the Web 
It's not uncommon for a unsuspecting employee to click on a link or download an 
attachment that they believe is harmless -- only to discover they've been infected with a 
nasty virus, or worse. 
9. Educate your employees 
Teaching your employees about safe online habits and proactive defense is crucial. 
Educating them about what they are doing and why it is dangerous is a more effective 
strategy than expecting your IT security staff to constantly react to end users’ bad 
decisions, Watchinski says. 
It's not easy: One of the most difficult things to do is protect end users against themselves, 
he adds. But ultimately, prevention is the best approach to handling your data security. 
Make sure your employees understand how important your company's data is, and all the 
measures they can take to protect it. 
10. Data encryption 
Encryption scrambles data, and is used to protect information that is being held on a 
computer, stored on external media such as DVDs or transmitted over a network. 
11. Intrusion detection 
These products monitor system and network activity to spot potential security breaches. If 
a detection system suspects an attack, it can generate an alarm, such as an email alert, 
based upon the type of activity it has identified. 
COMPUTER VIRUS 
What is it? 
 An executable computer program written intentionally to alter the way a 
computer operates without permission, to do harm to the computer. 
Types of Computer Viruses 
• Macro Viruses – are programmed as macros and embedded into a file or document and 
when the document is opened the virus is activated. A macro is a list of commands or 
actions that are found under key names of headings. Macro viruses typically infect global
COMPUTER OPERATIONS  PACKAGES 
settings files such as Word templates so that subsequently edited documents are 
contaminated with the infective macros 
• Boot Sector Viruses – A virus which attaches itself to the first part of the hard disk that is 
read by the computer upon bootup. These are normally spread by floppy disks. They only 
affect the computer’s boot sector such that the next time you try to start the computer it 
fails to boot 
• Time Bomb – is designed to cause damage to a computer at a specified date and time, 
rmmakaha@gmail.com 41 
e.g. Friday 13th, March 6th 
• Logic Bomb – checks for particular conditions or states of the system which when satisfied 
triggers the perpetration of an unauthorized and usually destructive act. It lies dormant for 
most of the time and is triggered by an event 
• Memory resident virus – resides in a computer’s volatile memory (RAM). 
• Polymorphic viruses – a virus that not only replicates itself by creating multiple files of itself, 
but it also its digital signature every time it replicates. This makes it difficult for less 
sophisticated antivirus software to detect 
• Program viruses e.g. cascade, pacman 1508, override. 
• Boot viruses e.g. pasta, pentagon, Michelangelo 
• Internet Viruses e.g. Trojan horse, Stealth 
DEFINITION2. 
A virus is acomputer program designed to enter yourcomputer and tamper with your files without 
your knowledge. Once the program containing the virus is open, the activated virus can not only 
infect other programs and documents on youcomputerr, it can duplicate and transmit itself to 
other computers that are connected to yours, just like a physical virus can move from one human 
host to another. 
Virusesbegan in the late 1980s as personal computers and electronic bulletin boards became 
more common. Back then, operating systems, word processing programs and other programs 
were stored on floppy disks. Hidden Viruseswere programmed onto these disks; as the disks were 
transferred from person to person, the virus spread. 
WHO CREATES VIRUSES? 
Where do Virusescome from? Every virus is created by an author with a different motive—but all 
virus builders feel their actions are justified. For some, a killer virus is the ultimate technical 
challenge, like climbing a mountain. For others, creating Viruses is a form of self-expression. Some 
disgruntled employees, consumers or citizens turn to virus building as revenge for perceived 
injustices. And though it’s a frightening thought, some Virusesare built and aimed by legitimate (but 
disreputable) businesses to weaken competitors. Other virus authors want to make their mark in 
Internet history; these writers get a thrill out of seeing their virus cause damage enough to attract 
news headlines both online and on the evening news. 
What Viruses Do? /Signs  symptoms of an infected computer. 
 Reduced memory or disk space 
 Files are overwritten or damaged 
 Hard drive may be erased 
 Data is modified /corrupted. 
 Change files  date stamp 
 Drive lights blink without reason 
 Longer times are experienced when loading programs 
 Slower system operation. 
• Deletion of data files 
• The computer completely fails to work 
• Erasure or deletion of executable files 
• Formatting of the hard disks 
• Filling up of disk space
COMPUTER OPERATIONS  PACKAGES 
• Programs suddenly take longer to load. 
• The size of a program changes. 
• The disk runs out of free space when it seems to have plenty. 
• The CHKDSK command does not show the correct amount of bytes available. 
• Bit errors frequently occur while running Windows. 
• The disk drive is active when it should not be. 
• The hard drive is inaccessible when booting from a floppy drive. 
• Unrecognized files appear. 
• File names change. 
• The keyboard makes a clicking noise. 
• The screen becomes distorted. 
• Text on screen does unusual things. 
• CMOS settings, AUTOEXEC.BAT, or CONFIG.SYS files change unexpectedly (Symantec). 
A large part of detection is anti-virus software. Like a doctor, anti-virus software often 
uses the above listed symptoms to identify and eradicate an infection. 
What are the symptoms of an infected computer? 
It’s not always easy to tell if your computer has been compromised. More than ever before, the 
authors of viruses, worms, Trojans and spyware are going to great lengths to hide their code and 
conceal what their programs are doing on an infected computer. That’s why it’s essential to follow 
the advice given in this guide: in particular, install Internet security software, make sure you apply 
security patches to your operating system and applications and backup your data regularly. 
It’s very difficult to provide a list of characteristic symptoms of a compromised computer because 
the same symptoms can also be caused by hardware and/or software problems. Here are just a 
few examples: 
• Your computer behaves strangely, i.e. in a way that you haven’t seen before. 
• You see unexpected messages or images. 
• You hear unexpected sounds, played at random. 
• Programs start unexpectedly. 
• Your personal firewall tells you that an application has tried to connect to the Internet (and 
it’s not a program that you ran). 
• Your friends tell you that they have received e-mail messages from your address and you 
haven’t sent them anything. 
• Your computer ‘freezes’ frequently, or programs start running slowly. 
• You get lots of system error messages. 
• The operating system will not load when you start your computer. 
• You notice that files or folders have been deleted or changed. 
• You notice hard disk access (shown by one of the small flashing lights) when you’re not 
aware of any programs running. 
• Your web browser behaves erratically, e.g. you can’t close a browser window. 
How computers are infected with Viruses? 
 Use of infected floppy diskettes on uninfected computers. Floppy disks or other media 
that users can exchange. 
 Downloading unknown files, when your computer is connected to the Internet. 
 Opening an E-mail attachment. Email attachments. 
 Accepting unknown program installations from the internet 
 Use of network files/direct connection/through networks. 
 Software piracy [buying software from unauthorized agents]. Pirated software. 
 Booting a PC from an infected medium. 
 Executing an infected program. 
 Opening an infected file. 
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COMPUTER OPERATIONS  PACKAGES 
 Shareware. 
 Viruses may be sent by opening email attachments, 
 clicking on spam, 
 visiting corrupt websites and links online, 
• Opening spreadsheets or even the original method—infected disks. 
• But the Internet is now the superhighway for virus transmission. 
rmmakaha@gmail.com 43 
Sharing of storage media 
• Through e-mail attachments 
• Networks – if your computer is connected to a home network or if your work computer is 
part of network, you may find yourself with an infection through no fault of your own. There 
isn’t much you can do to stop these kinds of infections, short of having your network 
administrator ensure that everyone’s antivirus software is up to date so that the invading 
bug can be removed as quickly as possible. 
• Internet downloads including software piracy 
• Rogue Websites. It is depressing to know that you may become infected with spyware or a 
virus by doing nothing more than simply visiting a website, but it is true. Many adult 
websites, gambling websites and other less than trustworthy websites will attempt to 
automatically access your computer when you visit them. They often install adware bugs 
that will cause a flurry of pop ups to appear on your screen. This adware will often allow for 
other programs with even more nefarious purposes to be installed and before you know it, 
your computer will be swamped. To stop these rogue websites, adjust the settings on your 
antivirus software and firewall so that no outside connections can be made and no 
programs can be installed without your express permission. 
CHARACTERISTICS and ATTRIBUTES OF COMPUTER VIRUSES 
The demonstrated characteristics of computer viruses include several remarkable items, including 
size, versatility, propagation, effectiveness, functionality, and persistence. 
1) Size.The sizes of the program code required for computer viruses has been demonstrated to be 
surprisingly small. This has facilitated the ability of these programs to attach themselves to other 
applications and escape notice for long periods of time. 
2) Versatility.computer viruses have appeared with the ability to generically attack a wide variety 
of applications. Many do not even require information about the program they are infecting. 
3) Propagation. Once a computer virus has infected a program, while this program is running, the 
virus is able to spread to other programs and files accessible to the computer system. The 
ability to propagate is essential to a virus program. 
4) Effectiveness. Many of thecomputer viruses that have received widespread publicity have had 
far-reaching and catastrophic effects on their victims. These have included total loss of data, 
programs, and even the operating systems. 
5) Functionality. A wide variety of functions has been demonstrated in virus programs. Some virus 
programs merely spread themselves to applications without otherwise attacking data files, 
program functions, or operating systems activities. Other virus programs are programmed to 
damage or delete files and systems. The effectiveness of these programs is enhanced through 
the use of several phases of operation, in which the virus propagates through a system or lies 
dormant until triggered by a specified event. This allows the virus program increased time to 
spread before the victim system's user becomes aware of its presence. 
6) Persistence. Even after the virus program has been detected, recovery of data, programs, and 
even system operation has been difficult and time consuming. In many cases, especially in 
networked operations, eradication of viruses has been complicated by the ability of the virus 
program to repeatedly spread and reoccur through the networked system from a single 
infected copy.
COMPUTER OPERATIONS  PACKAGES 
rmmakaha@gmail.com 44 
Attributes of computer viruses 
o Auto replicating [self replicating]. 
o Attaches itself to a program or file 
o It infects as it travels 
o Reproduces itself 
o Distribute itself 
o Copies itself 
o Duplicate copies of itself 
o It spreads 
o It is software 
o It can destroy 
o It hides 
DESTRUCTIVE EFFECTS OF COMPUTER VIRUSES 
o Cause damage to data 
o Extract data from machines for spying or theft 
o Slow machine performance 
o Corrupt data 
o Damage software, hardware and files 
o Damage the computer by damaging programs 
o Reformatting of the hard disk 
o Deletion of files 
ANTIVIRUS TOOLS/PACKAGES/SOFTWARE 
1) Dr Solomon’s Antiviral 
Package 
2) Norton Antivirus Package 
3) AVG Antivirus 
4) Microsoft Antiviral Package 
5) McAfee VirusScan 
6) F-PROT anti-virus package 
7) Protector Plus 2000 for 
Windows ver 7.2.H03 
8) Anti Trojan Elite ver 3.7.5 
9) Panda Antivirus platinum 7 
ver 7.06 
10) AntiSpy ver 4.4.2 
11) avast! 4 Professional Edition 
ver 4.6.652 
12) DrWeb® Anti-Virus, Home 
Edition ver 4.30a 
13) Dr.Web Anti-Virus for 
Workstations ver 4.30.a 
14) File Sharing Sentinel ver 1.0.1 
15) Real Password Protector 
2005 ver 2.0 
16) Code(Red) Hunter v1.5 ver 
v1.5 
17) Digital Patrol ver 5.00.12 
18) BitDefender 
19) Kaspersky 
20) F-Secure Anti-Virus 
21) PC-cillin 
22) ESET Nod32 
23) CA Antivirus 
24) Norman Virus Control 
25) AntiVirusKit 
26) AVAST! 
27) Panda Titanium 
28) Windows OneCare 
29) ViRobot Expert 
30) PCTools AntiVirus 
31) WinAntiVirus 
32) CyberScrub AntiVirus 
33) The Shield AntiVirus
COMPUTER OPERATIONS  PACKAGES 
SCANNER – examine every file on a specific disk drive, looking/searching for known virus 
“signatures”. A “signature” is a string of software code that identifies a virus program. Every virus 
has a unique signature 
MEASURES/FACILITIES PROVIDED BY AN ANTIVIRUS PACKAGE. 
1. Scanning – searching for viruses 
2. Cleaning of the system (removal of viruses) 
3. Rearrangement of corrupted data. 
4. Repairing of corrupted data files. 
5. Quarantine – separation of infected files from uninfected files. 
6. Prevention includes creating user awareness, implementing hygiene rules, using disk 
authorization software, or providing isolated 'quarantine' PCs. 
7. Detection involves the use of anti-virus software to detect, report and (sometimes) 
rmmakaha@gmail.com 45 
disinfect viruses.. 
8. Containment involves identifying and isolating the infected items. 
9. Recovery involves disinfecting or removing infected items, and recovering or replacing 
corrupted data. 
PRECAUTIONS/SAFETY GUIDES AGAINST VIRUSES 
 Install a reliable antiviral package 
 Avoid Software piracy thus buy software from authorized dealers. 
 Never download unknown files from the internet 
 Boot the system from virus free disks 
 Using write protect tabs on floppy disks 
 Scan every floppy diskette for viruses before use. Unknown floppy diskettes should 
not be used 
 Avoid using foreign storage media 
 Use genuine software 
 Avoid opening e-mails from suspicious or unknown sources 
 Write protect disks 
 Install antivirus software, e.g. Avira, Eset Nod32, AVG, Norton, Dr. Solomon’s Toolkit 
• Install a reliable anti virus program – From the first moment you turn your computer on, you should 
have a trusted anti virus program by your side. Even if you have a machine that isn’t hooked up to 
the Internet, a reliable anti virus program is a low cost and common sense addition to any 
machine. There are even free anti virus programs you can download that work almost as well as 
industry giants like Norton and McAfee. 
• Install anti-spyware and anti-malware programs – As good as the best anti virus programs are, they 
sometimes need a little bit of help. Thankfully, many of the top anti-spyware programs are 
completely free. Spybot Search and Destroy and CCleaner are just two free programs that can 
help prevent computer viruses from doing any damage on your machine. As helpful as these 
programs are, however, you must update them and run them on a regular basis for them to do 
any good. 
• Avoid suspicious websites – A good virus protection program will alert you when you visit a website 
that attempts to install or run a program on your computer. Many less than reputable adult 
websites do this, so if you get a warning, don’t go back, you may end up with a bug you can’t get 
rid of. 
• Never Open Email Attachments Without Scanning Them First – The most common way viruses are 
spread throughout the Internet is still via email. Some attachments, like pictures, now display in 
emails and don’t require an attachment to be manually opened, but other documents do. Make 
sure you use an email client that scans all email attachments before you are allowed to open 
them. This will help prevent computer viruses from getting a foothold on your machine. 
• Set up Automatic Scans – Many of the top anti virus programs, as well as the best anti-spyware 
programs, now have settings that will let them automatically run during down times or in the 
middle of the night. Of course, your computer must be on for this to happen, but having daily 
scans run when nothing else is going on is a great way to prevent even the latest computer viruses
COMPUTER OPERATIONS  PACKAGES 
from sticking around too long. 
• Watch Your Downloads – Part of the fun of the Internet is downloading music, movies and other 
items. However, since these downloads are so massive, it can be easy to sneak a virus along for 
the ride. Only download these files from trusted sites that you can count on, or, at the very least, 
scan them before you open them. 
• Updates, Updates, Updates – There is a reason why Windows has a feature called Critical Updates. 
There is an entire branch of Microsoft dedicated to staying one step ahead of the hackers out 
there so when they manage to fix a possible security loophole, you need to download the patch 
right away. Help Microsoft help you prevent computer viruses from causing too much trouble. 
• Know What To Look For – Even if you are just a casual computer user, you should have an idea of 
how your machine operates, what normal pop up windows look like and what popular viruses are 
out there, that way, when your computer begins exhibiting tell tale signs, you’ll know. You can help 
prevent computer viruses by staying updated and educated. 
• Stay Away From Cracked Software – It is so secret that you can download illegal, cracked versions 
of some programs online. As tempting as it may be, these files are almost always infested with 
advanced and difficult to detect bugs. Play it safe and get your software from the source. 
• Install a Firewall – A firewall is a program that screens incoming Internet and network traffic. Along 
with your virus program, it can help prevent unauthorized access to your computer. 
• Be prepared to Lock Down – If you hear of a virus that is spreading like wildfire through the Internet, 
make an extra effort to be careful. Don’t open any suspicious emails or accept any downloads for 
a week or two until your virus protection program has been updated and you are, once again, 
safe. 
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COMPUTER LANGUAGES 
(a) Machine Language 
 A computer language made up of binary digits (0s and 1s) 
 The most fundamental way to program a computer, using instructions made up entirely of 
strings of 0sand 1s. 
 The language is far from English and any mathematical notation. 
 Machine language is not portable and is machine dependent meaning it cannot be moved 
from one machine to the other. 
 Errors are very difficult to remove and programs are difficult to write using machine language. 
(b) Low Level Language 
 Low level means the language can better communicate with the system. 
 LLL are closer to machine code 
 They use mnemonics i.e. ADD to add SUB to subtract etc 
 Easier for a programmer to write a program in LLL than machine language. 
 Programs have to be translated from source code into machine language 
(c) High Level Language 
 A programming language that utilizes macroinstructions and statements that closely resembles 
human language or mathematical notation to describe the problem to be solved or the 
procedure to be used. 
 Programs are much easier to write / read because the are next English 
 [English like statements]. 
 A programming language where each instruction corresponds to several machine code 
instructions. A compiler or interpreter must translate instructions in this language before they 
can be processed. 
MACHINE LANGUAGE 
ADVANTAGES DISADVANTAGES 
• A very powerful language 
• No translation is needed 
• Much harder to code for programmers 
because it’s a series of 1s  0s. 
• Not portable 
• Machine Dependent 
• Errors are difficult to remove 
LOW LEVEL LANGUAGE
COMPUTER OPERATIONS  PACKAGES 
ADVANTAGES DISADVANTAGES 
• Easier to use than machine language • Machine dependent 
• Harder to code than HLL 
• Not portable 
HIGH LEVEL LANGUAGE 
ADVANTAGES DISADVANTAGES 
• It is a portable language 
• Programs are much easier to read/ 
write coz it’s close to English language. 
• Programs are problem oriented. 
• Errors are removed before translation to 
Machine code [during compiling]. 
• Slower in execution 
• Programs tend to be wordy hence they 
take long to compile. 
• Requires more memory. 
 LANGUAGE TRANSLATOR PROGRAMS 
 A Translator is a program that translates a source program/code into an equivalent object 
code [machine code] before the program is executed by the computer. 
rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 47 
 Compiler 
 Translates a complete program written in HLL into machine code before it is 
executed. 
 Produces a translated document. 
 E.g. COBOL compiler. 
 Assembler 
 Translates a source program written in assembly language into machine code. 
 Interpreter 
 A computer program that translates one statement at a time [source code] and 
generates the machine code for that statement only  executes it there  there before 
moving to the next line/statement. 
 Interpreter translates line per line and does not produce a translated document. 
 E.g. Pascal Interpreter, BASIC Interpreter. 
Compare  contrast Interpreter  Compiler 
1) Compiler- fast execution of program. 
2) Interpreter- Slowed down execution of program. 
3) Compiler- compiler time overhead. 
4) Interpreter- No compiler time overhead 
5) Compiler- Stand alone executables 
6) Interpreter- Dependency on interpreter 
7) Compiler- Compiler is complex [time, space] 
8) Interpreter- Relative simplicity of interpreter 
List the advantages  disadvantages of interpreters  compilers. 
1. A compiled program will always run faster than an interpreted one 
2. Object code generated by compilers may be saved on disk  run as many times as required 
without being compiled. 
3. A compiler gives more helpful error messages. 
4. Compiler gives the line number where the error has occurred. 
5. An interpreter will find the error at the first instance whereas the compiler will list all errors after 
compiling. 
6. A compiler will check the syntax of the entire program whereas the interpreter only checks the 
syntax of statements that are executed during that particular run of a program. 
7. Interpreters are very convenient for program development, since making modifications does 
not mean the whole program has to be reloaded  recompiled which takes considerable 
time. 
8. Interpreter is cheaper than compiler  is simpler to use
COMPUTER OPERATIONS  PACKAGES 
9. Many interpreters will allow a program to run up to a point where an error occurs, let the 
programmer fix the error  then continue to run the program from that point. 
10. With an interpreter debugging is easier since the code is executed line by line. 
11. Line by line interpretation can be slow 
12. Interpreter can test your code as you write it 
13. With an Interpreter there is no need to create object code  link programs. 
Language Processors and Translator Programs 
• These are programs that are used to convert high and low level language programs into 
machine code, i.e. into a form directly understood by the computer. There are three main 
types of translator programs: 
• Human programmers write programs in a language that is easy to understand for them 
• They use language translators to convert that program into machine language – a 
language that is easy to understand for the processor 
Translation process 
rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 48 
Source code 
(Human 
readable) 
a) Assemblers 
They translate programs written in assembly language into machine code 
b) Interpreters 
Convert HLL programs into machine by translating one program statement at a 
time before it can be executed. No object code is stored, e.g. QBASIC 
Interpreter translates the HLL program one statement at time. It reads a single 
statement, translates it into machine language and passes that machine 
language code to the processor and then translates the next statement, and so 
on … 
c) Compilers 
Like interpreters they also translate HLL programs into machine code. They 
however differ from interpreters in that a whole program is translated at a time. 
The object code which is created can either be executed immediately or saved 
for later execution. 
Compiler translates the program written in a HLL in one go. The translated code is 
then used by the processor whenever the program needs to be run 
Development Software/Programming Languages 
It allows the user to create software for various applications. All software programmes (systems and 
application) are written in coding schemes called programming languages. The primary function 
of a programming language is to provide instructions to the computer system so that it can 
perform a processing activity to achieve an objective or solve a problem. Programme code is the 
set of instructions that signal the CPU to perform circuit-switching operations. Programming 
languages have four categories: 
• Low-level languages 
• High-level languages 
• Fourth generation languages 
• Fifth generation languages 
Object code 
(Machine 
readable)
COMPUTER OPERATIONS  PACKAGES 
rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 49 
Low Level Languages 
• Low level computer languages are machine codes or close to it. 
• Computer cannot understand instructions given in high level languages or in English. It can 
only understand and execute instructions given in the form of machine language i.e. 
language of 0 and 1. 
• There are two types of low level languages. The lowest-level language is Machine 
Language, which hides no details of the machine; not even the bit patterns used to form 
instructions are abstracted. 
• Low-level languages have the advantage that the programmer is able to tune the code 
to be smaller or more efficient, and that more system-dependent features are sometimes 
available. They have the disadvantage that they are often (usually?) harder to program 
with than HLLs. 
First generation languages (abbreviated as 1GL) 
• The most elementary and first type of computer, which was invented, was machine 
language. Machine language was machine dependent. 
• A program written in machine language cannot be run on another type of computer 
without significant alterations. Machine language is sometimes also referred as the binary 
language i-e, the language of 0 and 1 where 0 stands for the absence of electric pulse 
and stands for the presence of electric pulse. Very few computer programs are actually 
written in machine language. 
• It is the lowest and most elementary level of programming language and was the first type 
of programming language to be developed. Machine language is basically the only 
language which computer can understand. 
• In fact, a manufacturer designs a computer to obey just one language, its machine code, 
which is represented inside the computer by a string of binary digits (bits) 0 and 1. The 
symbol 0 stands for the absence of electrical pulse and 1 for the presence of an electrical 
pulse. Since a computer is capable of recognizing electric signals, therefore, it understands 
machine language. 
• Represent the very early, primitive computer languages that consisted entirely of 1's and 
0's - the actual language that the computer understands (machine language). 
• The main benefit of programming in machine code is that the code a user writes can run 
very fast and efficiently, since it is directly executed by the CPU. However, machine code 
is a lot more difficult to learn than higher generational programming languages, and it is 
far more difficult to edit if errors occur. 
Advantages of Machine Language 
i) It makes fast and efficient use of the computer. 
ii) It requires no translator to translate the code i.e. directly understood by the 
computer 
Disadvantages of Machine Language:
COMPUTER OPERATIONS  PACKAGES 
i) All operation codes have to be remembered 
ii) All memory addresses have to be remembered. 
iii) It is hard to amend or find errors in a program written in the machine 
language 
iv) These languages are machine dependent i.e. a particular machine 
language can be used on only one type of computer 
Second generation languages (2GL) – Assembly Language 
• As computer became more popular, it became quite apparent that machine language 
programming was simply too slow tedious for most programmers. Assembly languages are 
also called as low level language instead of using the string of members programmers 
began using English like abbreviation to represent the elementary operation. 
• The language provided an opportunity to the programmers to use English like words that 
were called MNEMONICS. 
• It was developed to overcome some of the many inconveniences of machine language. 
This is another low level but a very important language in which operation codes and 
operands are given in the form of alphanumeric symbols instead of 0’s and l’s. 
• These alphanumeric symbols will be known as mnemonic codes and can have maximum 
up to 5 letter combination e.g. ADD for addition, SUB for subtraction, START,LABEL etc. 
Because of this feature it is also known as ‘Symbolic Programming Language’. This 
language is also very difficult and needs a lot of practice to master it because very small 
• English support is given to this language. The language mainly helps in compiler 
orientations. The instructions of the Assembly language will also be converted to machine 
codes by language translator to be executed by the computer. 
• It represents a step up from the first generation languages. Allow for the use of symbolic 
names instead of just numbers. Second generation languages are known as assembly 
languages. Code written in an assembly language is converted into machine language 
(1GL). 
• Assembly language consists of letters of the alphabet. This makes programming much 
easier than trying to program a series of zeros and ones. As an added programming assist, 
assembly language makes use of mnemonics, or memory aids, which are easier for the 
human programmer to recall than are numerical codes. 
Advantages of Assembly Language 
i) It is easier to understand and use as compared to machine language. 
ii) It is easy to locate and correct errors. 
iii) It is modified easily 
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COMPUTER OPERATIONS  PACKAGES 
Disadvantages of Assembly Language 
i) Like machine language it is also machine dependent. 
ii) Since it is machine dependent therefore programmer Should have the knowledge 
of the hardware also. 
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High Level Languages 
• The assembly languages started using English like words but still it was difficult to learn 
these languages. High level languages are the computer language in which it is much 
easier to write a program than the low level language. 
• High level computer languages give formats close to English language and the purpose of 
developing high level languages is to enable people to write programs easily and in their 
own native language environment (English). High-level languages are basically symbolic 
languages that use English words and/or mathematical symbols rather than mnemonic 
codes. Each instruction in the high level language is translated into many machine 
language instructions thus showing one-to-many translation 
Advantages of High Level Language 
• User-friendly 
• Similar to English with vocabulary of words and symbols 
• They require less time to write. 
• They are easier to maintain. 
• Problem oriented rather than 'machine' based. 
• Program written in a high-level language can be translated into many machine 
language and therefore can run on any computer for which there exists an 
appropriate translator. 
• It is independent of the machine on which it is used i.e. Programs developed in 
high level language can be run on any Computer 
• Easier to learn and understand than an assembler language as instructions 
(statements) that resemble human language or the standard notation of 
mathematics. 
• Have less-rigid rules, forms, and syntaxes, so the potential for error is reduced. 
• Are machine-independent programs therefore programs written in a high-level 
language do not have to be reprogrammed when a new computer is installed. 
• Programmers do not have to learn a new language for each computer they 
program. 
• Instructions are much easier to remember and use that assembly language 
instructions 
• Fewer instructions are required to write a program than when using assembly 
language. 
• A program can usually be developed much more quickly using a high level 
language than an assembly language. 
• A program written in a high level language on one type of computer can usually 
be converted to operate on another type of computer quite easily. Because of 
this high level language programs are described as being portable. 
• 
Disadvantages of High Level Language 
• A high-level language has to be translated into the machine language by a 
translator and thus a price in computer time is paid.
COMPUTER OPERATIONS  PACKAGES 
• The object code generated by a translator might be inefficient Compared to an 
equivalent assembly language program 
• Types of computer languages - as we human beings communicate with each 
others in different language such as Urdu, French, Punjabi and Arabic etc. Similarly 
to communicate with the computers we have to use specific languages and for 
this purpose hundreds of languages have been developed 
• Less efficient than assembler language programs and require a greater amount of 
computer time for translation into machine instructions. 
• High level language programs normally take up more space and execute more 
slowly than equivalent assembly language programs 
Types of High Level Languages 
Many languages have been developed for achieving different variety of tasks, some are fairly 
specialized others are quite general purpose. 
These are categorized according to their use as 
a) Algebraic Formula-Type Processing. These languages are oriented towards the computational 
procedures for solving mathematical and statistical problem 
Examples are 
• BASIC (Beginners All Purpose Symbolic Instruction Code). 
• FORTRAN (Formula Translation). 
• PL/I (Programming Language, Version 1). 
• ALGOL (Algorithmic Language). 
• APL (A Programming Language). 
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b) Business Data Processing: 
• These languages emphasize their capabilities for maintaining data processing procedures 
and files handling problems. Examples are: 
• COBOL (Common Business Oriented Language). 
• RPG (Report Program Generator 
b) String and List Processing: These are used for string manipulation including search for patterns, 
inserting and deleting characters. Examples are: 
• LISP (List Processing). 
• Prolog (Program in Logic). 
Object Oriented Programming Language 
In OOP, the computer program is divided into objects. Examples are: 
• C++ 
• Java 
e) Visual programming language: these are designed for building Windows-based applications 
Examples are: 
• Visual Basic 
• Visual Java
COMPUTER OPERATIONS  PACKAGES 
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• Visual C 
Third generation languages (3GL) 
With the languages introduced by the third generation of computer programming, words and 
commands (instead of just symbols and numbers) were being used. These languages therefore, 
had syntax that was much easier to understand. 
• Third generation languages are known as high level languages and include C, C++, Java, 
and JavaScript, among others. 
Fourth generation languages (4GL) 
§ The syntax used in 4GL is very close to human language, an improvement from the 
pervious generation of languages. 4GL languages are typically used to access databases 
and include SQL and ColdFusion, among others. 
VERY HIGH LEVEL LANGUAGES (VHLL) 
Fifth generation languages (5GL) 
Fifth generation languages are currently being used for neural networks. A nueral network is a form 
of artificial intelligence that attempts to imitate how the human mind works. 
• 5GL is an abbreviation for fifth-generation language. Fifth-generation programming 
languages emerged along with the research in Artificial Intelligence (AI). Most constraint-based 
and logic programming languages and some declarative languages are fifth-generation 
languages. Fifth-generation languages are designed to make 
the computer solve the problem for you as oppose to using an algorithm written by a 
programmer. 
• The idea of fifth generation languages was popular in 1990s. Japan put much research 
and money into their fifth-generation computer systems project. Prolog, Mercury, and 
OPS5 are the best known fifth-generation languages. 
• These are used to create programs for artificial intelligence and expert system and are 
sometimes called natural languages because they use English syntax. Allow programmers 
to communicate with the computer using normal sentences. 
GENERIC SOFTWARE AND THE ORGANISATION OF DATA 
Define Software 
Are basically programs, which are in a computer system?
COMPUTER OPERATIONS  PACKAGES 
Computer programs and procedures concerned with the operation of a computer system. 
Definitions of software on the Web: 
• Written coded commands that tell a computer what tasks to perform. For example, Word, 
PhotoShop, Picture Easy, and Photo Deluxe are software programs. 
• Coded instructions (programs) that make a computer do useful work. 
Computer software refers to the various programs or instructions that are stored in the computer 
(stored program concept) and used to either manage or control the operation of a computer 
system or to direct the computer in solving specific problems. Software is divided into two major 
types. 
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SOFTWARE HIERARCHY 
TYPES OF SOFTWARE
COMPUTER OPERATIONS  PACKAGES 
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SYSTEM SOFTWARE 
• Refers to the operating system and all utilityprograms that manage computerresources at 
a low level. Programs that control and support operations of a computer system. 
• Systems software includes compilers, loaders, linkers, and debuggers. 
• System software includes a variety of programs such Operating Systems, DBMS, 
Communication control programs. Service and utility programs, and programming 
language translators. 
• Definitions of system software 
A term for a complicated set of programs that act together to allow a computer, and 
other programs, to function. Different from an page layout application that the user may 
have, system software is what allows the page layout application to interact with the 
monitor display, the RAM, the hard drive and the rest of the computer. 
OPERATING SYSTEM 
• The main control of a computer system. 
• It is a system of programs that controls  coordinates the execution of computer programs 
and may provide scheduling, debugging, input/output control, system accounting, 
compilation, storage assignment, data management and related services. 
Definitions of operating system on the Web: 
• The software that the rest of the software depends on to make the computer functional. 
On most PCs this is Windows or the Macintosh OS. Unix and Linux are other operating 
systems often found in scientific and technical environments. 
• A computer program that controls the components of a computer system and facilitates 
the operation of applications. Windows Me, Windows XP, Linux, and MacOS are common 
operating systems. 
APPLICATION SOFTWARE 
o Applications software comprises programs designed for an end user, such as word 
processors, database systems, and spreadsheet programs. 
o Programs that specify the information processing activities required for the completion of 
specific tasks of computer users. E.g. Electronic Spreadsheet and word processing 
programs or inventory or payroll programs.
COMPUTER OPERATIONS  PACKAGES 
o Software that is designed and written for a specific personal, 
organizational, or processing task, such as graphics software. 
o These programs accomplish the specialized tasks of the user, while 
operating system software allows the computer to work. A computer-aided 
dispatch system is application software, as is each word processing 
program. 
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FREEWARE 
 Public domain softwarethat is freely available in magazines and on the internet at 
no charge to users though manuals may be offered at a cost. Freeware may or 
may not have copyrights and may or may not have distribution restrictions. 
SHAREWARE 
 Refers to software that is widely distributed in much the same way as freeware BUT 
is always copyrighted and includes a software license that requires its users to pay 
for the privilege of using the software beyond a certain trial period. If you decide 
to use it, you are expected to pay for the license. There is usually a disabling 
system in the program after a certain period of time i.e. a month. 
OPERATING SYSTEM 
 Are programs that create an environment, which enables us to use computers? 
 Is an integrated system of program that manages the operations of the CPU, controls the 
input/output and storage resources and activities of the computer system, and provides 
various support services as the computer executes the application programs? 
 Is a set of software routines that communicate between application programs and the 
hardware? 
 All communications go through the operating system. 
 E.g. when a user issues a command to print, the O/S receives the command  
processes it according to priorities with the use of interrupts. 
 Once the processor is free to execute the command, the O/S sends the message 
to the processor  receives the output, which is then directed to the printer. 
MAJOR OPERATING SYSTEMS 
MS-DOS (Microsoft Disk Operating System) 
• It has been widely used especially before 1995 when the new Windows 95 took over. 
• It is a single user operating system – only one user can be using the system at a given time. 
• It is a single tasking operating system – It allows for the processing of only one task at a time 
• Use of short prompt commands – the user interfaces with the computer system through the 
use of commands that are fed into the computer usually after the prompt sign () e.g. 
C:cls (Command to clear the screen) 
• Instructions are put in only through the keyboard 
• Once a file is deleted it can never be recalled 
• The operating system is not user-friendly 
Windows 
• A windows based operating system is more advanced than the MS-DOS based operating 
system. 
• It features graphical user interfaces (GUIs) – User can feed commands into the computer 
through the selection of relevant icons, bars, buttons, boxes or other forms of images 
(mostly resembling the intended device or operation). 
• True multitasking – the operating system allows for numerous tasks to be done at the same 
time. 
• Networking – the operating system is multi-usable – many users can use it at the same time. 
It is capable of holding a number of computer systems networked together.
COMPUTER OPERATIONS  PACKAGES 
• Multimedia Presentations- the operating system allows for the presentation of information 
in a variety of media including text, graphic displays, voice and other audio, photographs 
and video. 
• Virtual Memory – It allows for the use of storage devices as extension of the main memory 
thus giving the appearance of a larger main memory than actually exists. 
• Deleted files go to the recycle bin 
• Makes use of easier input methods, e.g. mouse, joystick 
• Windows operating system has MS-DOS option 
• Examples of Windows Operating Systems packages, Windows NT (new technology) and 
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Windows 95. 
• In computer terms, a window is one section of a computer’s multiple section display 
screen that can have a different display. 
OS/2 
• It is called the Operating System /2 
• It is an operating system developed by IBM and was introduced in 1994 with the OS/2 
Warp version as the latest one. 
• It provides graphical user interfaces (GUIs), multitasking, virtual memory and 
telecommunications. 
UNIX 
• Originally developed by ATT but now being offered by many other vendors. 
• It is a multitasking, multi-user and net-work managing operating system 
• Because of its portability, it can be used on mainframes, midrange computers and 
microcomputers. 
• It is a popular choice for network servers. 
The Macintosh System/Mac OS 
• It is an operating system for Apple from Macintosh microcomputers 
• It is a popular GUI as well as multitasking and virtual memory operating system. 
Types /EXAMPLES of operating systems 
There are several types of operating system, defined according to whether they can 
simultaneously manage information measuring 16 bits, 32 bits, 64 bits or more. 
OPERATING SYSTEM PROGRAMMING SINGLE USER MULTI USER SINGLE TASK MULTI TASK 
1. MS DOS 16 bits X X 
2. Windows3.1 16/32 bits X not pre-emptive 
3.Windows95/98/Me 32 bits X cooperative 
4.WindowsNT/2000 32 bits X pre-emptive 
5.WindowsXP 32/64 bits X pre-emptive 
6.Unix / Linux 32/64 bits X pre-emptive 
7.MAC/OS X 32 bits X pre-emptive 
8.VMS 32 bits X pre-emptive 
9.Windows Vista 
10.Windows 7
COMPUTER OPERATIONS  PACKAGES 
BOOTING(also known as booting up) is a bootstrapping process that starts operating systems 
when the user turns on a computer system. A boot sequence is the initial set of operations that the 
computer performs when power is switched on. The bootloader typically loads the main operating 
system for the computer. 
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Rebooting 
Hard reboot 
 A hard reboot (also known as a cold reboot, cold boot or cold start) is when power to 
a computer is cycled (turned off and then on) or a special reset signal to the 
processor is triggered. This restarts the computer without first performing any shut-down 
procedure. (With many operating systems, especially those using disk caches, 
after a hard reboot the filesystem may be in an unclean state, and an automatic 
scan of on-disk filesystem structures will be done before normal operation can begin.) 
It may be caused by power failure, be done by accident, or be done deliberately as 
a last resort to forcibly retrieve the system from instances such as a critical error or 
virus-inflicted DoS attack. It can also be used by intruders to access cryptographic 
keys from RAM, in which case it is called a cold boot attack. 
Soft reboot 
 A soft reboot (also known as a warm reboot) is restarting a computer under software 
control, without removing power or (directly) triggering a reset line. It usually, though 
not always, refers to an orderly shutdown and restarting of the machine. 
 The Control-Alt-Delete key combination on the original IBM PC was designed to allow 
a soft reboot for a quicker and more convenient (and, some argue[who?], less stressful 
on system components) restart than powering the computer completely down then 
back up. 
 This kind of reboot will not usually reset the hard disks, so that they have time to 
update their write cache to permanent storage. Hard disks will also keep their 
configuration (like C/H/S adjustments, HPA, DCO, internal passwords...) over these 
reboots. 
 The Linux kernel has optional support for the kexecsystem call, which transfers 
execution to a new kernel and skips hardware or firmware reboot. The entire process 
is done independent of the system firmware. Note that the kernel being executed 
does not have to be a Linux kernel. 
 Sometimes, the computer does not respond and in that case it can be restarted by 
pressing Ctrl+Alt+Del keys. The process of starting the computer using these keys is 
called warm booting or softbooting. 
Random reboot 
 Random reboot is a non-technical term referring to an unintended (and often undesired) 
reboot for which the cause is not immediately evident to the user. Such reboots may occur 
due to a multitude of software and hardware problems, such as triple faults. 
 As Windows XP/Vista has an option to skip its Blue Screen of Death (Blue Screens of Death 
in Windows XP/Vista offer no option of pressing any key and seeing if the computer 
continues functioning) and immediately restarts the computer in the event of a fatal error, 
users can be mistaken in thinking a Windows XP/Vista computer suffers from random 
rebooting. 
 Also, If a Wii game has a disc failure or the Wii game disk is dirty, it will reboot to the Wrist 
Strap screen. 
Errors 
 In Windows, when an error occurs in the boot process, a Blue Screen of Death or a Black 
Screen of Death may occur. On UNIX and Unix-like operating systems, such as Linux, a fatal 
error in the boot process may cause a kernel panic. 
FACTORS ONE SHOULD CONSIDER WHEN 
• Making comparisons of the microcomputer operating systems available in 
the organization 
• Making microcomputer operating system acquisition decision.
COMPUTER OPERATIONS  PACKAGES 
 Is the OS a single or multitasking operating system? Many microcomputer OS are 
single tasking, meaning they allow only one person to run one program at a time. 
Multitasking and multi-user OS permit more than one program to run and more than 
one person to use the system at one time. Multitasking OS may allow a user to receive 
a fax message at the same time one is searching a database. 
 Is it a task switching operating system? A task switching OS lets one load more than 
one program at a time and allows switching between the programs. The task that one 
is working with is the foreground task and the suspended tasks are background tasks. 
 What utilities are available with the OS? Some of the most commonly used utilities on 
microcomputer OS are delete, copy contents of one diskette to another, format a 
diskette, delete files stored in a diskette, and compress data. 
 Is the OS hardware dependent? An OS may be limited to running on specific hardware 
or may have versions that allow it to run on different types of computer systems. 
 What user interface is offered by the operating system? Graphical User Interface and 
Command Driven User Interface are examples of user interfaces. See Interface 
section. 
Types of operating systems 
 Multiprocessing 
 Multitasking 
 Multi-user 
 Multi programming 
 Single user 
Modes of operation/ Operating system techniques 
Computers can operate in many different ways requiring different and complex operating systems. 
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Real time processing 
 When the computer has to react within a guaranteed time to an input, a real time 
operating system is used. For example, the engine management system within a car 
uses a real time operating system in order to react to all the things going on within the 
engine. A real time operating system does not necessarily have to be fast. It simply has 
to be quick enough to respond to inputs in a predictable way. Embedded computers 
often contain an RTOS as many are used to control something. 
 Computers operating in real time are often dedicated to the control of systems such 
as industrial processes, planes and space flights. Another example of real time 
processing is computer games. For example, when an action is selected in a game, 
the data is fed back to the computer and the systems updated. 
Multi-programming 
 Multi-programming is a method of operating such that several programs appear to be 
running at once. 
 The jobs are usually given priorities. The operating system switches jobs in and out of 
processor time according to priority. For example, while one job is being allocated 
printer time, another will be being processed in memory. The processor is so fast that it 
seems that many jobs are being processed at the same time. 
Multi-tasking 
 This isn't just about running more than one application at the same time. Multi-tasking 
allows multiple tasks to run concurrently, taking turns using the resources of the 
computer. 
 This can mean running a couple of applications, sending a document to the printer 
and downloading a web page. 
 However, operating systems are not truly multi-tasking - in order to do this, you would 
need parallel processors, which are now appearing on personal computers. 
Multiprocessing 
 An operating system technique which can manage multiple instruction processors, 
assigning each to operate upon a different instruction stream (program or job) 
concurrently.
COMPUTER OPERATIONS  PACKAGES 
 Multiprocessing is the use of two or more central processing units (CPUs) within a single 
computer system. The term also refers to the ability of a system to support more than one 
processor and/or the ability to allocate tasks between them.[1] There are many variations 
on this basic theme, and the definition of multiprocessing can vary with context, mostly as 
a function of how CPUs are defined (multiple cores on one die, multiple chips in one 
package, multiple packages in one system unit, etc.). 
 Multiprocessing sometimes refers to the execution of multiple concurrent software 
processes in a system as opposed to a single process at any one instant. However, the 
terms multitasking or multiprogramming are more appropriate to describe this concept, 
which is implemented mostly in software, whereas multiprocessing is more appropriate to 
describe the use of multiple hardware CPUs. A system can be both multiprocessing and 
multiprogramming, only one of the two, or neither of the two. 
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Multi-access or multi-user 
 A multi-access (or multi-user) system is one where a number of users are able to use the 
same system together. 
 Modern personal computers can allow multi user access i.e. more than one person can 
make use of the computer resources at the same time via a LAN. 
 The central processor deals with users in turn; clearly the more users, the slower the 
response time. Generally, however, the processor is so fast that the response time at the 
most is a fraction of a second and the user feels they are being dealt with immediately. 
o Multi-user is a term that defines an operating system or application software that 
allows concurrent access by multiple users of a computer. Time-sharing systems 
are multi-user systems. Most batch processing systems for mainframe computers 
may also be considered multi-user, to avoid leaving the CPU idle while it waits for 
I/O operations to complete. However, the term multitasking is more common in 
this context. 
o An example is a UNIX server where multiple remote users have access (such as via 
Secure Shell) to the UNIX shell prompt at the same time. Another example uses 
multiple X Window sessions spread across multiple terminals powered by a single 
machine - this is an example of the use of thin client. 
o Management systems are implicitly designed to be used by multiple users, 
typically one system administrator or more and an end-user community. 
Single-user 
 Is most commonly used when talking about an operating system being usable only by one 
person at a time, or in reference to a single-user software license agreement. Multi-user 
operating systems such as UNIX sometimes have a single user process available for 
emergency maintenance. 
Batch processing 
 A batch processing system is where programs or data are collected together in a batch 
and processed in one go. Typically the processing of payrolls, electricity bills, invoices and 
daily transactions are dealt with this way. 
 This method of operation lends itself to jobs with similar inputs, processing and outputs 
where no human intervention is needed. Jobs are stored in a queue until the computer is 
ready to deal with them. Often batch processed jobs are done overnight. 
ROLES (functions) OF THE OPERATING SYSTEM 
The operating system has various roles: 
1. Management of the processor: the operating system is responsible for managing 
allocation of the processor between the different programmes using a scheduling 
algorithm. The type of scheduler is totally dependent on the operating system, 
according to the desired objective. 
The OS is responsible for managing the allocation of processor time to the different 
programs that will be using the computer. The processor can only execute one 
instruction at a time and in a multi-user system, conflicts are bound to arise when 
several user programs request usage of the processor at the same time. The OS
COMPUTER OPERATIONS  PACKAGES 
therefore allocates processor time to all users either in a round robin fashion or using a 
system of priorities. 
2. Management of the random access memory: the operating system is responsible for 
managing the memory space allocated to each application and, where relevant, to 
each user. If there is insufficient physical memory, the operating system can create a 
memory zone on the hard drive, known as virtual memory. The virtual memory lets 
you run applications requiring more memory than there is available RAM on the 
system. However, this memory is a great deal slower. 
The OS is responsible for managing the memory space allocated to each application. 
If there is insufficient physical memory the OS can create a memory zone on the hard 
drive known as virtual memory which lets you run applications requiring more memory 
than is available on the system. 
The operating system is responsible for the following activities in connections with 
memory management. 
Keep track of which parts of memory are currently being used and by whom. 
Decide which processes to load when memory space becomes available. 
Allocate and deallocate memory space as needed 
3. 
4. Management of input/output: the operating system allows unification and control of 
access of programmes to material resources via drivers (also known as peripheral 
administrators or input/output administrators). 
5. Management of execution of applications: the operating system is responsible for 
smooth execution of applications by allocating the resources required for them to 
operate. This means an application that is not responding correctly can be killed. 
6. Management of authorisations: the operating system is responsible for security relating 
to execution of programmes by guaranteeing that the resources are used only by 
programmes and users with the relevent authorisations. 
7. File management: the operating system manages reading and writing in the file 
system and the user and application file access authorisations. 
The OS manages reading from and writing to files and also controls the creation, 
manipulation and access to files. 
The operating system is responsible for the following activities in connections with file 
management: 
 File creation and deletion 
 Directory creation and deletion 
 Support of primitives for manipulating files and directories 
 Mapping files onto secondary storage 
 File backup on stable (nonvolatile) storage media 
8. Information management: the operating system provides a certain number of 
indicators that can be used to diagnose the correct operation of the machine. 
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9. ERROR DETECTION 
The OS is responsible for detecting and any hardware or software malfunctioning and 
reporting them to the user 
10. USER/SYSTEM INTERFACE 
The OS acts as an interface between the computer and the user, hiding all the 
complexities of the computer from the user and making the computer more user 
friendly 
11. PREPARATION OF A SYSTEM LOG 
The OS compiles a report on the events that take place in a computer from the time a 
user logs on to a computer, what he/she does up to the time he/she logs off 
Additional Functions of the operating system: 
 Controls and coordinates the computer system
COMPUTER OPERATIONS  PACKAGES 
 Scheduling and loading of jobs to provide continuous processing. So that no parts of the 
computer system are idle for any significant period of time. 
 It is a platform for application programs 
 Provides user interface 
 Acts as an interface between hardware and application programs 
 Provides error correctional routines 
 Control over selection and operation of input 
 Records details of processing for control analysis 
 File management, control the creati 
 Memory management, allocates memory to various jobs or tasks 
 Multiprogramming, multiprocessing, multitasking, timesharing, housekeeping  handling 
errors. 
input-output devices  file handling. 
creation, deletion, saving and access of files 
 Resource management manages processor time, memory space, di 
peripheral devices. 
 Reports errors when they occur. 
 Task management. Manage the accomplishment of the computing tasks of end users. It 
may involve multitasking capability where several computing tasks can occur at the 
same time. 
 Minimizes the amount of human intervention required during processing. 
COMPUTER INTERFACE 
 Refers to the type of interaction between two elements. 
 Is part of the operating system that allows you to communicate with it or the computer so 
that you can load programs, 
 When a person interacts with a computer he uses a User Interface, which can be a screen, 
keyboard, mouse, scanners or other input devices. 
Definitions of interface on the Web: 
• The interaction between the computer a 
between a computer and its peripherals. 
 Basically the interface can be 
 Command driven 
provide users with flashes of text and in which users would general 
their command to perform an action. 
 Menu driven 
 GUI- point and click 
 WIMP interface 
1. Command line interfaces (MS 
A command line interface allows the user to interact with the computer by 
The computer displays a prompt, the user keys in the comman 
COMMAND-LINE INTERFACE (CLI) 
or software by typing commands to perform specific tasks. This text 
the use of a mouse pointer with a 
text user interface (TUI) to select options. 
Features of a command line interface include: 
In the early days of personal computers, all PCs used command 
• Commands - usually abbreviated 
command will not work. 
• Experienced users who know the commands can work very quickly without having to find 
their way around menus. 
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disk space and 
. access files, and accomplish other tasks? 
and the user or the control of the flow of data 
driven- include operating systems and database languages that 
MS-DOS BASED OPERATING SYSTEM) 
typing in commands 
command and presses enter or return. A 
is a mechanism for interacting with a computer operating system 
text-only interface contrasts with 
graphical user interface (GUI) to click on options, or menus on a 
command-line interfaces. 
- must be typed correctly and in the right order or the 
62 
sk nd generally type in 
commands. 
d )
COMPUTER OPERATIONS  PACKAGES 
• An advantage of command driven programs is that they do not need the memory and 
processing power of the latest computer and will often run on lower spec machines. 
• Command driven programs do not need to run in Windows. 
• A command line interface can run many programs, for example a batch file could launch 
half a dozen programs to do its task. 
• An inexperienced user can sometimes find a command driven program difficult to use 
because of the number of commands that have to be learnt. 
An example of a common command-driven interface is MS-DOS, the original operating system for 
all Microsoft-compatible PCs. The MS-DOS command to display all files on drive a would be: dir c:. 
2. Graphical user interfaces (WINDOWS BASED OPERATING SYSTEM) 
Graphical user interface is sometimes shortened to GUI. The user chooses an option usually by 
pointing a mouse at an icon representing that option. A GRAPHICAL USER INTERFACE (GUI) is a type 
of user interface item that allows people to interact with programs in more ways than typing such 
as computers; hand-held devices such as MP3 Players, Portable Media Players or Gaming devices; 
household appliances and office equipment with images rather than text commands. A GUI offers 
graphical icons, and visual indicators, as opposed to text-based interfaces, typed command labels 
or text navigation to fully represent the information and actions available to a user. 
rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 63 
Features of GUIs include: 
• They are much easier to use for beginners. 
• They enable you to easily exchange information between software using cut and paste or 
'drag and drop'. 
• They use alot of memory and processing power. It can be slower to use than a CLI if you 
are an expert user. 
• They can be irritating to experienced users when simple tasks require a number of 
operations. 
When discussing user interfaces, it is important to note that Windows XP, OS/X and Linux are all 
graphical user interfaces. 
A good user interface should: 
• be attractive and pleasing to the eye 
• allow the user to try out different options easily 
• be easy to use 
• use suitable colours for key areas 
• use words that are easy to understand aimed at the type of user 
• have online help 
It also should consider the needs of the users. For example, young children are likely to prefer 
pictures to words and people with disabilities may benefit from particular input or output devices 
3. WIMP interface 
• Windows, Icons, Menus and Pointer - a method by which a user can interact with a 
computer without having to learn lots of special words - it provides a much more intuitive 
'view' of the computer and its facilities than non-WIMP operating systems provide 
• Windows, /images/, Menus and Pointer, or Windows, /images/, Mouse and Pull-down 
menus This is a graphical interface which makes access to computers much more 
straightforward and intuitive than the main alternative, the command-line interface. The
COMPUTER OPERATIONS  PACKAGES 
WIMP interface has been used on Apple Macintosh computers since they w 
and are coming into use on PCs through Microsoft Windows and on Unix and other 
workstations through the X Window system. 
4. Menu driven interfaces 
The user is offered a simple menu 
further menu. Part of the screen may have an instruction followed by a numbered list of options to 
choose from: 
A full screen menu takes up most of the screen. 
A menu bar is the set of options at the top of the screen. When an option is chosen a 
menu may be offered. 
Features of menu driven interfaces include: 
• They are easy to use as the user does not have to remember sets of commands. 
• They are user friendly - you can often guess your way around the options. 
• They can be irritating if there ar 
command line interface you can go to the option required immediately. 
Dialog box 
In graphical user interfaces, a dialog 
to display information to the user, or to get a response if needed. They are so 
form a dialog between the computer and the user 
requesting input from the user, or both. It provides controls that allow you 
out an action. 
Scrollbar 
A scrollbar (Also known as a handle in the very first GUIs) is a graphical object in a 
continuous text, pictures or anything else can b 
viewed even if it does not fit into the space in a 
Taskbar 
In computing, taskbar is a desktop display bar used to 
incorporated a taskbar in Windows 95 
graphical user interface ever since. Other 
include a taskbar. Other operating systems use terms such as 
Toolbar 
In a graphical user interface on a 
buttons, icons, menus or other input or output elements are placed. 
WYSIWYG 
WYSIWYG, is an acronym for What 
describe a system in which content displayed during editing appears very similar to the final 
output,[2] which might be a printed document, web page, slide presentation or even the lighting 
for a theatrical event. 
The phrase was originally a catch phrase 
(from Rowan  Martin's Laugh-In 
would often say What you see is what you get to excuse her quirky behavior. 
Meaning 
WYSIWYG implies a user interface 
result while the document is being created. In general WYSIWYG implies the ability to directly 
manipulate the layout of a document without having to type or remember names of layout 
commands. The actual meaning depends on the user's perspective, e.g. 
• In Presentation programs 
display precisely represents the appearance of the pa 
does not necessarily reflect how the page will be printed unless the printer is specifically 
matched to the editing program, as it was with the 
Apple Macintosh. 
rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 
were invented, 
from which to choose an option. One menu often leads to a 
r are too many levels of menus to move around - 
(or dialogue) box is a special window, used in user interfaces 
so-called because they 
user—either informing the user of something, or 
to specify how to carry 
GUI 
be scrolled including time in video applications, i.e., 
computer display, window, or viewport. 
launch and monitor applications. 
and it has been a defining aspect of Microsoft Windows 
desktop environments, such as KDE and GNOME 
ude Panel or Dock. 
computer monitor a toolbar is a GUI widget on which onscreen 
hat You See Is What You Get. The term is used in computing 
popularized by Flip Wilson's drag persona Geraldine 
in the late 60s and then on The Flip Wilson Show until 1974), who 
en that allows the user to view something very similar to the end 
programs, Compound documents and web pages, WYSIWYG means the 
page displayed to the end 
Xerox Star and early versions of the 
64 
ere pull down 
with a 
, with which 
, Microsoft 
Windows's 
GNOME, also 
to 
, ge end-user, but
COMPUTER OPERATIONS  PACKAGES 
• In Word Processing and 
Desktop Publishing applications, WYSIWYG means the display 
simulates the appearance and precisely represents the effect of fonts and line breaks on 
the final pagination using a specific 
500-page document can accurately refer to a reference three hundred pages later. 
printer configuration, so that a citation on page 1 of a 
• WYSIWYG also describes ways to manipulate 3D models in 
aided design, 3D computer graphics 
design tool used in the theatre industry for pre 
Menu bar 
A menu bar is a region where computer menus 
application-specific menus which provide access to such functions as opening files, interacting 
with an application, or help. Menu bars are typically present in 
windows. 
Menu bar from Mozilla Firefox. 
SYSTEM SOFTWARE- consists of programs that manage and support a computer system and its 
information processing activities. T 
computer system hardware and the application programs of end users. 
System software is computer software 
provide a platform for running a 
The most basic types of system software are: 
• The computer BIOS and device 
control the hardware connected to or built into the computer. 
• The operating system (prominent examples being 
Linux), which allows the parts of a computer to work together by performing tasks like 
transferring data between 
also provides a platform to run high 
• Utility software, which helps to analyze, configure, optimize and maintain the computer. 
In some publications, the term system software 
tools (like a compiler, linker or debugger 
Computer purchasers seldom buy a computer primarily because of its system software. Rather, 
system software serves as a useful (even necessary) level of infrastructure code, generally built 
pre-installed. 
In contrast to system software, software that allows 
play games, listen to music, or surf the web is called 
Types of system software programs 
System software helps use the operating system and computer system. It includes diagnostic tools, 
compilers, servers, windowing systems, utilities, language translator, data communication 
programs, database systems and more. The purpose of system software 
applications programmer as much as possible from the complexity and specific details of the 
particular computer being used, especially memory and other hardware features, and such 
accessory devices as communications, printers, readers, d 
Specific kinds of system software include: 
• Loaders 
• Linkers 
• Utility software 
• Desktop environment / Graphical user interface 
• Shells 
rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 
Stereochemistry, Computer 
and is the brand name of Cast Software's lighting 
pre-visualisation of shows. 
are housed. Its purpose is to house window 
n, graphical user interfaces 
These programs serve as a vital software interface between 
designed to operate the computer hardware and to 
application software. 
firmware, which provide basic functionality to operate and 
Microsoft Windows, Mac OS X 
), memory and disks or rendering output onto a display device 
high-level system software and application software 
, is also used to designate software develop 
debugger). 
users to do things like create text documents, 
application software. 
is to insulate the 
displays, keyboards, etc. 
65 
, Computer- 
window- or 
with 
hese onality and 
device. It 
software. 
development 
built-in or
COMPUTER OPERATIONS  PACKAGES 
• BIOS 
• Hypervisors 
• Boot loaders 
• Database Management Systems(SQL, NoSQL) 
If system software is stored on non-volatile memory such as integrated circuits, it is usually termed 
firmware. 
3 functional categories of system software 
System management programs 
 Programs that manage the hardware, software, and data resources of 
the computer system during its execution of the various information 
processing jobs of users. 
 The most important system management programs are operating systems 
and operating environments, followed by telecommunications monitors  
Database Management Systems. 
System support programs 
 Programs that support the operations and management of a computer 
system by providing a variety of support services. 
 Major support programs are system utilities, performance monitors,  
security monitors. 
System development programs 
 Programs that help users develop information system programs 
and procedures and prepare user programs for computer 
processing. 
 Major development programs are language translators, 
programming tools and CASE [computer-aided software 
engineering] packages. 
APPLICATION PACKAGES/SOFTWARE 
 Are programs that are or were developed to solve specific user problems? 
 Word processors and spreadsheets fall into this category. 
 Software application packages can be custom built or they can be bought off the shelf. 
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# APPLICATION 
SOFTWARE 
DESCRIPTION EXAMPLES 
1 Word processing 
software 
• A word processor is used to produce documents such as letters, 
memos and reports. The latest versions of word processing software 
contain many features and can also be used for desktop publishing 
to create newsletters, brochures, business cards, signs and more. The 
latest word processing software will allow you to easily type into 
columns, add pictures and charts to your page, create custom 
borders, and experiment with a variety of type faces (fonts) in a wide 
range of sizes. You can even combine different fonts on the same 
page. 
• Word processing software offers many exciting formatting and editing 
features to make your work easier. You can easily check the spelling of 
a word or the entire document. The built in thesaurus will help you find 
an alternate word to use. Blocks of text can be easily moved, copied 
or erased. 
• Use this kind of tool to create worksheets, type letters, type papers, 
etc, e.g. MS Word, WordPerfect,.... 
• Ms word, 
Word 
perfect, 
Word star, 
• Ms works 
word 
processor 
,WordPro 
2 Spreadsheet 
software 
• A spreadsheet is used to manage, analyze and present numeric 
information. Some common uses of spreadsheet software are financial 
reports, personal finances and business finances. Spreadsheet 
programs can also create a chart from the numeric data. 
• Ms Excel, 
Lotus 1-2-3
COMPUTER OPERATIONS  PACKAGES 
• The working screen is laid out in rows and columns, much like a ledger. 
The information is typed into a cell. A cell is the intersection of a row 
and a column. The cell can contain a number, a word or phrase 
(generally used to identify what the number represents, such as a 
column or row heading), or a math function or formula. 
• Spreadsheets allow you to use simple math expressions such as add, 
subtract, multiply or divide, or advanced math such as the type of 
calculations performed by architects, engineers, economists and 
scientists. Spreadsheets also have a special group of built-in formulas, 
called functions, that let you perform calculations without having to 
type long, complex formulas. Functions are grouped into categories, 
such as financial, statistical, engineering, logical, math and 
trigonometry, database and list management, date and time, and 
information. 
• One of the reasons many people use a computer for their spreadsheet 
projects is because it is easy to change your information once it has 
been entered. If you change a number, the spreadsheet will 
automatically recalculate the results. You can also take advantage of 
this feature to perform a what-if analysis. For example, you input the 
data for a small business venture you are considering and the 
spreadsheet calculates your net profit for the first year of business. If 
you are not pleased with the result, you can change a few numbers to 
see how the change would affect the outcome. 
• Use this kind of tool to compute number-intensive problems such as 
budgeting, forecasting, etc. A spreadsheet will plot nice graphs very 
easily, e.g. MS Excel, Quattro Pro, Lotus 1-2-3, 
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3 Database 
management 
software 
• Allows user to prepare reports based on data found in different 
records. DBMS is an important managerial decision support tool for 
managers at all levels of the organization. A database is an organised 
store of information, for example an address book, list of employees, 
list of students, customers or items of assets. Database package is used 
to store records. Data can be sorted or filtered for separate viewing. 
Also Calculations and comparisons between data items can be done. 
Popular database packages are: Microsoft Excel, lotus Approach, 
Paradox, dBase IV, Data Ease. 
• Use this software to store data such as address, membership and other 
text information. A database can be used to easily sort and organize 
records 
• Ms 
Access, 
DbaseIV, 
Oracle 
4 Payroll • Pay plus , 
Pay well 
5 Accounting e.g. Pastel, TurboCash, QuickBooks • Pastel, 
Tetra 2000 
6 Presentation 
graphics software 
• Lets users or managers prepare slides containing charts, text and 
images. Presentation graphics software usually provides libraries of clip 
art images that can be cut and pasted into a slide to make the slide 
more attractive and informative. These are applications designed 
solely for designing graphs and text charts/posters and often used to 
produce slides for use on overhead projectors, or presentations on 
computer-projectors. They can also produce various types of charts. 
Examples of graphics packages are: Microsoft PowerPoint, Lotus 
Freelance, Harvard Graphics and Corel Draw, HyperStudio, Flash, 
Director. 
• Use this software to create multimedia stacks of cards/screens that 
can effectively present a lesson or a sales pitch. The user often clicks 
• Ms 
PowerPoin 
t, Lotus 
freelance 
graphs
COMPUTER OPERATIONS  PACKAGES 
on buttons to advance to the next screen in a sequence 
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7 Desktop 
Publishing 
• Use this software to make signs, banners, greeting cards, illustrative 
worksheets, newsletters, etc 
• Desktop Publishing (DTP) applications give users powerful and versatile 
page design capabilities. The user can incorporate text and graphics 
on very exact page layouts. These applications produce magazines, 
catalogues, invitation cards, business cards and other sophisticated 
documents. It links up well with other applications as the user can 
import text and graphics from the other applications. Examples of DTP 
packages are: Microsoft Publisher, PageMaker, Ventura and Frame 
maker. 
• Ms 
publisher, 
Aldus 
8 Multimedia i) Internet Browsers 
This software allows one to surf the Web. Often they can read email and 
create Web pages too, e.g. Netscape Navigator (or Netscape 
Communicator), MS Internet Explorer, AOL Browser.... 
ii) Email programs 
These programs send and receive email, e.g. Netscape Messenger (part of 
Netscape Communicator), MS Outlook Express, MS Outlook, Eudora, AOL 
browser (has email built in).... 
iii) Graphics Programs (pixel-based) 
This software allows one to touch up photographs and create graphics 
from scratch, e.g Adobe Photoshop, Paint Shop Pro, MS Paint (comes free 
on Windows PC's), Painter, .... 
• Internet 
explorer 
Netscape 
9 Communication • This software allows two computers with modems to communicate 
through audio, video, and/or chat-based means, e.g. MS NetMeeting, 
AOL Instant Messenger, IRC, ICQ, CU-SeeMe, ... 
• Ms 
Outlook, 
Ms 
Exchange 
10 Design e.g. AutoCad, Corel Draw • AutoCAD, 
CAM 
State five advantages of using a word processor (e.g. MS Word) rather than a manual typewriter in 
an office [10]. 
 Ability to correct mistakes 
 Ability to view documents on screen before printing 
 Ability to incorporate diagrams 
 Ability to move parts of text to other sections of the document. 
 Ability to save or store documents for future reference or use. 
 Ability to alter or change document layout. 
 Ability to print a lot of copies [ no retyping] 
 Ability to insert tables 
 Ability to format document [font, paragraphs, bullets etc] Spelling and grammar checker 
 Import files 
 Mail merge 
 WYSIWYG capability 
 Creation of templates 
 Automatic creation of index and table of contents 
o ther - Good reasoning [ 2 marks each for 5  1 mark each for more than 5] 
a) Explain what is meant by the term ‘word processing package’. [3 marks]
COMPUTER OPERATIONS  PACKAGES 
 Is a program or set of programs used to enter, edit, format, store and print 
documents. A document may be anything from a single memo to a complete 
book. 
 An application package that involves the use of computers to manipulate 
text data in order to produce office communications in the form of 
documents. 
 Any of many popular application programs designed for composing, revising, 
printing, and filing written documents. 
 Word Processing is the efficient and effective production of written 
communications at the lowest possible cost through the combined use of 
systems management procedures, automated technology, and 
accomplished personnel. The equipment used in word processing 
applications includes but is not limited to the following: dictation and 
transcription equipment, automatic repetitive typewriters, visual display text 
editing typewriters, keyboard terminals, etc. 
b) Give any 2 examples of a word processing package’. [2marks] 
 MS WORD 
 WORD STAR 
 WORD Perfect 
 MS WORKS WORD 
c) Briefly describe any 5 important features of a word processor. [5 marks] 
1) Spelling and grammar checker 
2) Import files 
3) Mail merge 
4) WYSIWYG capability 
5) Creation of templates 
6) Automatic creation of index and table of contents 
d) List any 10 facilities that spreadsheets offer. [10 marks] 
1. Format cells, rows and columns, specifying for example, the alignment of text, number 
of decimal points, height and width of a cell. 
2. Copy cell contents to other locations 
3. Determine the effect of several different hypothetical changes of data 
4. Insert, move or delete rows and columns 
5. Use functions such as SUM, AVERAGE, MAX, MIN in formulae 
6. Create a simple database and sort or query the data to produce a report 
7. Write macros to automate common procedures 
8. Create templates i.e. spreadsheets with formats and formulae already entered, into 
which new figures may be inserted. 
9. Create multi-dimensional spreadsheets using several sheets, and copy data from one 
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sheet to another 
10. Create many different types of charts and graphs 
Shortcomings of spreadsheets 
While spreadsheets are a great step forward in quantitative modeling, they have deficiencies. At 
the level of overall user benefits, spreadsheets have four main shortcomings. 
• Spreadsheets have significant reliability problems. Research studies estimate that roughly 
94% of spreadsheets deployed in the field contain errors, and 5.2% of cells in unaudited 
spreadsheets contain errors. 
• The practical expressiveness of spreadsheets is limited. Several factors contribute to this 
limitation. Implementing a complex model requires implementing detailed layouts, cell-at-a- 
time. Authors have difficulty remembering the meanings of hundreds or thousands of cell 
addresses that appear in formulas. 
• Collaboration in authoring spreadsheet formulas is difficult because such collaboration 
must occur at the level of cells and cell addresses. By comparison, programming
COMPUTER OPERATIONS  PACKAGES 
languages aggregate cells with similar meaning into indexed variables with names that 
indicate meaning. Although some spreadsheets have good collaboration features, 
authoring at the level of cells and cell formulas remains a significant obstacle to 
collaboration in authoring spreadsheet models. On the other hand, many people 
collaborate on entering numerical data and many people can use the same spreadsheet. 
• Productivity of spreadsheet modelers is reduced by the cell-level focus of spreadsheets. 
Even conceptually simple changes in spreadsheets (such as changing starting or ending 
time or time grain, adding new members or a level of hierarchy to a dimension, or 
changing one conceptual formula that is represented as hundreds of cell formulas) often 
require large numbers of manual cell-level operations (such as inserting or deleting 
cells/rows/columns, editing and copying formulas, re-laying out worksheets). Each of these 
manual corrections increases the risk of introducing further mistakes. 
These four deficiencies in high-level benefits have deeper causes that, ironically, flow directly from 
the signature strength of spreadsheets (that they capture the structure of models in terms of 
WYSIWYG sheet layout for authors and report users). 
• Spreadsheets capture model logic in terms of sheet layout, especially contiguous layout of 
cells in a table. Spreadsheets have weak or nonexistent methods to capture higher level 
structures such as named variables, segmentation dimensions, and time series. 
• Formulas are subordinated to the cell layout. This forces the sheet layout to carry the 
structure of the model, not variables and formulas that relate variables. This also causes a 
large proliferation of cells, formulas and cell-level tasks even when only a few basic 
concepts are involved in a model. This forces authors to think and work at the level of cells 
instead of at the level of the natural concepts and structures of the model. 
• Formulas expressed in terms of cell addresses are hard to keep straight and hard to audit. 
Research shows that spreadsheet auditors who check numerical results and cell formulas 
find no more errors than auditors who only check numerical results. 
• Proliferation of error-prone manual cell-level operations contributes to all four of the high-level 
problems listed above. 
Criteria for Selecting Applications Software: 
• Accuracy - it must be free from errors 
• Flexibility – it must be able to adapt to changing environment. 
• Compatibility - it must be compatible with available hardware and software 
• Recency - it must be current 
• Cost - it must have reasonable cost 
• Originality - It must be original 
• Support - consider continued support from the supplier. 
• Ease of use - it must be user friendly. 
• Performance - it must have efficiency in both response time and run time. 
• Memory requirements 
Factors to consider when buying application software 
1. Cost. This includes the original cost of the package, technical support, and upgrades. 
2. Portability, can it be installed on one type of hardware or a variety 
3. Relevance of the software to the task at hand. 
4. Compatibility with existing hardware  software. Will the package run on existing 
hardware? Can files be easily transferred from existing systems without re-keying? Can 
files created in the package be exported to other systems in use in the company? 
5. It should be on a media compatible with your computer i.e. if you purchase software on 
CD media your computer should have compact disk drive. 
6. Sophistication, simple programs are usually easy to learn, cost less and are appropriate for 
those who use the software infrequently. 
7. Should include enough documentation such as installation instructions, system 
requirements e.g. Pentium 4, reference manual, registration information, supplier details 
and user manual. 
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COMPUTER OPERATIONS  PACKAGES 
8. Standard software, which is well supported locally i.e. used by most people in that area 
9. Is the application upgradeable and does it support future upgrades. 
10. Easiness of installation 
11. Technical support. Is support available? Is it very costly? Often, technical support contract 
can add 50% or more to the price of a package, but without it no support at all will be 
given by the manufacturer. 
12. Easy of learning. Are tutorials supplied? Are books on the software available in 
bookshops? Are training courses available? 
13. Easy of use and user- friendliness. Is it easy to use, for example using pull down menus, 
icons, helpful error messages when you do something wrong? 
14. Is the application from a reputable supplier e.g. Microsoft. 
15. Do you have enough resourceson your PC to install it e.g. it may require 256MB RAM, 
80GB HDD. Memory requirements; software packages vary in the amount of memory they 
require. Will the system require expenditure on more powerful hardware? 
16. Does the version of the product that I am considering run on my personalcomputer 
system? Is it compatible with my platform (PC, Macintosh, Sun, and so on)? with the 
processor used in my computer (486, Pentium, Motorola 6040, PowerPC, and so on)? and 
with the operating system that I am running (DOS, Windows, NeXT Step, UNIX)? 
17. Is the product compatible with other programs, such as extensions and device drivers, 
that I have on my personalcomputer system? 
18. Does the product do all that I want it to do? Is it simple enough to use immediately but 
powerful enough to provide the capabilities that I will want as my familiarity with the 
program increases? 
19. Is the product an up-to-date, current version or release? 
20. Does the product have a clear, step-by-step tutorial? Is the product easy to learn? 
21. Is the product accompanied by clear, easy-to-follow instructions, or documentation? 
22. Does the manufacturer provide technical assistance? Is a toll-free technical assistance 
number included in the software documentation? Does the manufacturer have a bulletin 
board or Internet address for technical assistance questions? Does the manufacturer 
charge for technical assistance? for product revisions or upgrades? 
23. Can I find instruction, or training, in the use of the product? 
24. Is the product from a respected, well known manufacturer? 
25. Does the program have any known problems, or bugs, and will these affect my use of the 
rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 71 
program? 
26. Does the product come with a warranty, and what are the conditions of that warranty? 
27. Does the product cost more or less than comparable products on the market? 
Benefits of application software to the user. 
 Installation should be easy, quick and should be provided by the vendor/supplier. 
 Good documentation is usually provided with the application for reference 
purposes. 
 Onsite assistance from the supplier or vendor 
 Provision of cheaper future upgrades upon acquisition of an application provided 
you have completed the registration information. 
 Value for money 
Applications software comes in different 'flavors' - or types: 
• Utility programs - these can be part of an operating system, but are also available for 
separate purchase. Examples include virus checkers, disk defragmenters, back up utilities 
and disk checker software. 
• Generic - general purpose software that is not written for any particular type of business. 
Examples of this include word processors and spreadsheets. 
• Integrated - a collection of software that has a common set of commands/icons. Usually 
they include word processors, spreadsheets and graphics software, but they can contain 
databases as well. They tend to be cheaper than purchasing each application separately. 
• Specific - software written for a defined purpose. Accountancy software is a good 
example of this, and can be bought by anyone.
COMPUTER OPERATIONS  PACKAGES 
• Bespoke - also known as 'tailor made'. A company may need a particular piece of 
software that it cannot purchase because it does not exist yet - or it does not like what is 
available. The company can commission the software to be specially written for them. This 
tends to be expensive. 
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SOURCES OF SOFTWARE 
1. Freeware 
o Freeware is the type of freely available software whose developer decides to distribute it 
for free. In contrast to the open source software, the source code in this case is not 
available for modifications and further development. Also, it should be noted that the 
distribution of the software may also be restricted by its developer, often allowing users to 
download it from his site only. Many free to download applications are available on the 
Internet. It is always wise to read the license before downloading the software. Many 
people tend to unknowingly share such applications with other people, without realizing 
that this may actually be illegal. 
2. Shareware 
o Shareware is very different from these other forms of free software and to some extent also 
a misnomer. The authors of shareware maintain their full intellectual right over shareware. 
The only difference between shareware and other commercially available software is that 
in this case the software is available for freely for trial for a limited number of days, or a 
limited number of times. After the expiry of the ‘free’ period, the users of shareware are 
required to pay for it. Source code and collaboration communities which exist around 
open source projects do not exist in this case. 
3. Off-the –shelf/generic or Commercial Software 
4. In-house/Custom made/Tailor Made/Bespoke software 
5. Outsourcing 
This involves contracting out software development to a software house - better known as 
outsourcing, especially where off-the-shelf packages are not available. 
Advantages 
o Software houses employ professionals and this may benefit the organisation 
o Transfer of skills to the existing professionals in an organisation 
o Organisation can get support from the contractor. 
Disadvantages 
o There could be breach of confidentiality. 
o Contractor may go bankrupt and cease trading leaving the user with no support. 
o Contractor might not have sufficient experience or understanding of the problem; 
thus the solution might not be satisfactory. 
o It takes time for the contractor to understand the user's business and operations, 
which makes the approach expensive. 
CLASSIFICATION OF SOFTWARE APPLICATIONS 
1. Commercial / generic Packages/Off the shelf software 
• Commercial software is computer software sold for profit; such software 
represented, until recently, the vast majority of all software used. 
• These are bought from a vendor. 
• Also known as off the shelf packages e.g. MS Office, Pastel. 
• Also known as work enhancement applications 
• Generic or Off the shelf software has the advantage of cost effectiveness due to 
larger market  the ability to incorporate available technology in the shortest 
possible time.
COMPUTER OPERATIONS  PACKAGES 
These increase the productivity  efficiency in the work place i.e. 
o Word Processing packages 
o Spreadsheet packages 
o Database /Information retrieval Packages 
o Graphics packages 
o Data communications Software 
• Off-the –shelf/generic or Commercial Software 
This is software that can be purchased, from a software company that develops programs 
and sells them to many computer users and organizations. Applications such as financial 
accounting, business graphics and pay roll may be bought. 
rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 73 
Advantages 
o Cheaper - the software company is able to spread the software development cost 
over a large number of customers, hence reducing the cost any one customer must 
pay. 
o Less risky - the software is in existence, hence you can analyse the features and 
performance of the package. 
o The program is a well-tried and tested product with few errors. 
o Less time - Off-the -shelf software is often installed quickly and easily. 
o The package is well documented 
o The packages require little maintenance 
o There is continued support from the supplier through upgrades. 
o It is cheaper than custom-written software. The development costs of the package 
may be millions of pounds, but the customer may be able to buy it for a few hundred 
pounds, since sales are made to thousands of other customers. 
o It is immediately available and already thoroughly tested so is unlikely to have major 
bugs in it 
o Documentation is usually available in the form of reference manuals, user guides and 
tutorials 
o Training courses may be available form third party trainers. 
o Technical support is usually available from the manufacturers via a Web site or 
telephone line [at a price]. 
o Other users of the package can be consulted as to its suitability before purchase. 
o Upgrades are usually available every year or two 
Disadvantages 
o The package may not do exactly what you want it to do; 
o It may not run on the firm’s existing hardware 
o It may not interface with other software already in use in the organization. 
o The organization might need to pay for the features that are not required and 
never used. 
o The package may be for general needs and therefore not ideal for the user. 
o The user has no direct control over the package, 
2. Homemade / Customized packages/ Tailor-made Software 
 Customized software is software designed around a company or other organization's 
processes to make those processes more efficient. 
 It is distinct from market software [commercial or generic], which approaches 
problems in a general way so that the product can be sold to more than one 
customer.
COMPUTER OPERATIONS  PACKAGES 
 Has been written by the vendor specifically for a user’s needs. Also known as in-house 
packages, tailor-made packages. 
 E.g. most payroll packages, billing software, product design applications 
 Is that application that has been written for a specific user’s needs by a software 
rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 74 
vendor? 
 It is non-standard software. 
• In-house/Custom made/Tailor Made/Bespoke software 
This approach requires a development team from within the organisation. The team is 
usually comprised of programmers and analysts. The team members should be of high 
calibre, highly trained and reliable. 
Advantages 
o Internal professionals understand operations better and therefore can produce an 
accurate solution. 
o The Software usually meets user requirements. 
o Management are in total control of the development process 
o More flexibility - there is more flexibility in making modifications. 
o Problem specificity - in-house developed software can give an organisation 
software programmes that are easily tailored to a unique problem or task. 
Disadvantages 
 Time and costs of developing the program may be greater than other options 
 In-house staff may lack the expertise needed for the project 
 Reliability of the resultant software is highly questionable. 
 In some cases the developers may attempt to gain fraudulently from the system 
 
Disadvantages 
1. Being customized, the non-standard software may not be used by any other organization. 
2. It has huge support costs after implementation. 
3. Dependency syndrome with the supplier. There is heavy reliance on the developers of the 
software for its continued existence  maintenance 
4. Future support may be difficult if the supplying company goes under, shuts down, or 
liquidate or if its development staff leaves. 
5. May not be upgradeable and may not run if moved to a new hardware platform. 
6. You are tied to a supplier of which you may not be willing to have a maintenance 
contract with. 
7. Written or Custom-built software performs a defined function and is expensive to build. 
8. Custom built is expensive to maintain 
9. Custom built software has reduced lifespan due to high speed of technological 
advancement in the field of computers. 
3. Managerial applications 
Help to make management decisions 
 Decision support systems 
 Database Management Systems Report Writing Tools 
MAKE NOTES ON: 
 How application packages solve problems? 
 Typical problems which can be solved by application packages 
 Customization of packages using macros 
Utility software 
Utility software (also known as service program, service routine, tool, or utility routine) is computer 
software designed to help manage and tune the computer hardware, operating system or 
application software by performing a single task or a small range of tasks. Some utility software has 
been integrated into most major operating systems. 
Examples 
• Disk storage utilities 
•
COMPUTER OPERATIONS  PACKAGES 
o Disk defragmenters can detect computer files whose contents are broken across 
several locations on the hard disk, and move the fragments to one location to 
increase efficiency. 
o Disk checkers can scan the contents of a hard disk to find files or areas that are 
corrupted in some way, or were not correctly saved, and eliminate them for a 
more efficiently operating hard drive. 
o Disk cleaners can find files that are unnecessary to computer operation, or take 
up considerable amounts of space. Disk cleaner helps the user to decide what to 
delete when their hard disk is full. 
o Disk space analyzers for the visualization of disk space usage by getting the size 
for each folder (including subfolders)  files in folder or drive. showing the 
distribution of the used space. 
o Disk partitioners can divide an individual drive into multiple logical drives, each 
with its own filesystem which can be mounted by the operating system and 
treated as an individual drive. 
o Backup utilities can make a copy of all information stored on a disk, and restore 
either the entire disk (e.g. in an event of disk failure) or selected files (e.g. in an 
event of accidental deletion). 
o Disk compression utilities can transparently compress/uncompress the contents of 
a disk, increasing the capacity of the disk. 
o File managers provide a convenient method of performing routine data 
management tasks, such as deleting, renaming, cataloging, uncataloging, 
moving, copying, merging, generating and modifying data sets. 
o Archive utilities output a stream or a single file when provided with a directory or a 
set of files. Archive utilities, unlike archive suites, usually do not include compression 
or encryption capabilities. Some archive utilities may even have a separate un-archive 
utility for the reverse operation. 
• System profilers provide detailed information about the software installed and hardware 
attached to the computer. 
• Anti-virus utilities scan for computer viruses. 
• Text and Hex Editors directly modify the text or data of a file. These files could be data or 
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an actual program. 
• Data compression utilities output a shorter stream or a smaller file when provided with a 
stream or file. 
• Cryptographic utilities encrypt and decrypt streams and files. 
• Launcher applications provide a convenient access point for application software. 
• Registry cleaners clean and optimize the Windows registry by removing old registry keys 
that are no longer in use. 
• Network managers check the computer's network, log events and check data transfer. 
• Command line interface (CLI) and Graphical user interface (GUI) Allows the user to 
contact and make changes to the operating system. 
INTEGRATED SOFTWARE 
 Integrated software is software for personal computers that combines the most commonly 
used functions of many productivity software programs into one application. 
 The integrated software genre has been largely overshadowed by fully functional office 
suites, most notably Microsoft Office, but at one time was considered the killer 
application type responsible for the rise and dominance of the IBM PC in the desktop 
business computing world. 
 In the early days of the PC before GUIs became common, user interfaces were text-only 
and were operated mostly by function key and modifier key sequences. Every program 
used a different set of keystrokes, making it difficult for a user to master more than one or 
two programs. Programs were loaded from floppy disk, making it very slow and 
inconvenient to switch between programs and difficult or impossible to exchange data 
between them (to transfer the results from a spreadsheet to a word processor document 
for example). In response to these limitations, vendors created multifunction integrated
COMPUTER OPERATIONS  PACKAGES 
packages, eliminating the need to switch between programs and presenting the user with 
a more consistent interface. 
 The potential for greater ease-of-use made integrated software attractive to home 
markets as well as business, and packages such as the original AppleWorks for the Apple II 
and Jane for the Commodore 128 were developed in the 1980s to run on most popular 
home computers of the day. 
 Context MBA was an early example of the genre, and featured spreadsheet, database, 
chart-making, word processing and terminal emulation functions. However, because it 
was written in Pascal for portability, it ran slowly on the relatively underpowered systems of 
the day. Lotus 1-2-3, which followed it, had fewer functions but was written in assembler, 
providing it with a speed advantage that allowed it to become the predominant business 
application for personal computers.[2] 
 The integrated software market of today is exemplified by entry-level programs such as 
Microsoft Works which are often bundled with personal computers as starter productivity 
suites. 
SOFTWARE SUITES/BUNDLED SOFTWARE 
• A software suite or application suite is a collection of computer programs, usually 
application software and programming software of related functionality, often sharing a 
more-or-less common user interface and some ability to smoothly exchange data with 
each other. 
• Sometimes software makers introduce suites that are little more than repackaged 
versions of older programs offered at a lower price. 
• The solution might be software suites or bundled software. A suite is a collection of the 
full-featured versions of each software application - word processing, spreadsheet, 
database management, graphics, communications and sometimes organizers. 
• These applications are from the same software manufacturer and are packaged together 
in a large box and sold at prices that are much lower than if they were purchased 
individually - usually less than half of the original collective price! The software applications 
contained in a suite or bundle are the same applications a professional user might 
purchase individually. No corners have been cut, and additional features may have been 
added such as a common interface that allows any of the programs to be accessed 
from the same main menu, a consistent screen layout used by each of the programs, 
and the ability to easily exchange data from one program to another. 
INTEGRATED SOFTWARE/BUNDLED SOFTWARE / SOFTWARE SUITE 
 SOFTWARE that contains several applications rolled into one.Integrated software usually 
includes word processing, spreadsheet, database, graphics and communication 
capabilities. Two popular Integrated softwarepackages are Microsoft Works and 
ClarisWorks: 
 In integrated software, you will be able to work on a spreadsheet to perform calculations, 
store addresses and phone numbers in a database and be able to link information from 
the spreadsheet  the database when you work with the word processor in the integrated 
package. 
 Object Linking Embedding [OLE] is a standard that, Allows applications to be linked 
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together. 
 OLE-DB allows applications to import virtually any form of data into the database. 
Definitions of integrated software on the Web: 
• A group of applications designed to work together and share data easily. 
Software that combines the features of several different applications in a single program 
(e.g. word processing, database, spreadsheet, graphics, and communications).. 
Advantages of integrated applications 
 Easy to use 
 Generally costs much less
COMPUTER OPERATIONS  PACKAGES 
 Require or needs less RAM 
 Ability to pass data from one module to another. 
 Takes up much less hard disk space 
 Better organization of information. Data is stored in the database, calculations in an 
electronic spreadsheet  images in a graphical application package 
The advantages of bundled software suites are 
• Low cost compared to buying each application separately 
• Option to install all of the programs at the same time or only the programs you want to use 
• Consistent interface from one application to another 
• The ability to share information between applications 
• Future upgrades can update each application all at the same time 
• Ideal for personal use, professional use, large or small business 
• Each application is the full-featured version 
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The disadvantages are 
• High initial cost 
• All applications are from the same manufacturer - you might prefer a word processor from 
one company, a spreadsheet from a different manufacturer, etc. 
• May be purchasing more software than you actually need 
• Installation of the entire suite of applications takes up a large amount of storage space on 
your internal hard disk 
• Several large manuals to study if you plan to master each application, or the package 
might not include printed manuals in order to keep the cost low 
Disadvantages 
 Limited portability. The same applications must exist on every computer that you wish to 
open the document. 
 Offer fewer features and less versatility than stand alone versions or software. 
 Functional limitation. Its rigid you cannot change it to suit your specific needs. 
EXAMPLES OF INTEGRATED SOFTWARE 
• Microsoft Office 97 
• Microsoft Works 
• Claris Works 
• Lotus SmartSuite 97 
• Microsoft Office 2003,2007,2010  2013 
OPEN SOURCE SOFTWARE 
• Open source is a type of software which is freely available and its source code is available 
for further development, modification. Generally all open source software have a 
community of developers who provide support, documentation and even binary versions 
of the software to people who may be interested in it. These additional services, though, 
may not be free monetarily. 
• There are several ongoing open source software projects. The open source nature of these 
projects means that there will be several people working on modifying and improving the 
software from around the world. Some such examples include the Web browser Mozilla 
Firefox, content management software like Drupal, Joomla etc. 
SOFTWARE COPYRIGHT 
The Copyright, Designs and Patents Act
COMPUTER OPERATIONS  PACKAGES 
Copyright is a legal concept, giving the creator of an original work exclusive rights to control its 
distribution for a certain time period. 
Copying computer software is therefore a breach of copyright and a criminal offence. The Act 
covers stealing software, using illegally copied software and manuals, and running purchased 
software on more machines than the license allows. 
The legal penalties for breaking the copyright law include unlimited fines and up to two years in 
prison. 
All the software that you use should be fully licensed. When you purchase software you usually are 
licensed to use it on just one computer. It is illegal to make copies of the software to use on other 
computers, even if they are your own. 
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Software licences can be: 
• Single user - licensed for installation on one computer 
• Multi-user - the license allows you to install the software on a named number of computers 
• Site-licence - the licence lets you install the software onto an unlimited number of 
computers, as long as they are on one distinct site such as a school 
Software protection 
Software companies try to prevent illegal copying of their disks using the following methods: 
• Copy protection - the disk (or CD-Rom) may be formatted in a special way so it cannot 
easily be copied. 
• Restricting the number of installations - each installation is recorded on an installation disk 
and only a certain number are allowed. 
• A registration key - a unique series of letters and numbers that is asked for when running 
the program. The software will not run if the registration key is not typed in correctly and 
online multiplayer games will not to run if another user is online who has used the same key. 
• A phone or Internet activation code - this requires the user to call a number or go online to 
register the product. They then receive a unique computer-specific serial number. 
• Encryption - data can be scrambled up and cannot be read without the correct software. 
• A Dongle - a piece of hardware that must be plugged into the computer to run the 
software. Each one contains a unique electronic serial number and as they are expensive 
to produce they are mostly used to protect high-end software packages. 
• Details of the user are built into the software - when the software is run it displays the 
original users name. This does not prevent the copying but it makes is obvious that the 
copy is illegal. 
• A Keyfile - a small file with a unique code that is placed in the same directory as the 
program. If the code is not valid then the software will not run. 
SOFTWARE PIRACY 
 Unauthorized copying of software. 
 unauthorized use or reproduction of copyrighted patented material. 
 unauthorized copying of software 
 The production of illegal copies of software. 
 By far, the biggest legal problem affecting the computer industry today is software piracy, 
which is the illegal copying or use of programs. Piracy is a huge problem mainly because 
it is so easy to do. In most cases, it is no more difficult to steal a program than it is to tape 
a music CD that you have borrowed from a friend. Software pirates give up the right to
COMPUTER OPERATIONS  PACKAGES 
receive upgrades and technical support, but they gain the use of the program without 
paying for it. 
Implications of Software piracy 
 Loss of business to software companies. 
 Lack of technical support, no connection with supplier upgrades. 
 Software incompatibility, may require a key, which you might not have, as a result 
you can’t install it. 
 Virus Spread 
 Lawsuits for copyright, which may be very costly in terms of reputation and money. 
 Piracy harms all software publishers, Regardless of their size. Software publishers 
spend years developing software for the public to use. A portion of every dollar 
spent in purchasing original software is channeled back into research and 
development so that better, more advanced software products can be produced. 
When you purchase pirated software, your money goes directly into the pockets of 
software pirates instead. 
 Software piracy also harms the local and national economies. Fewer legitimate 
software sales result in lost tax revenue and decreased employment. Software piracy 
greatly hinders the development of local software communities. If software 
publishers cannot sell their products in the legitimate market, they have no incentive 
to continue developing programs. Many software publishers simply won’t enter 
markets where the piracy rates are too high, because they will not be able to 
recover their development costs. 
 Software piracy harms everyone in the software community including you, the end 
user. How? 
1) Piracy results in higher prices for duly licensed users, 
2) Piracy reduces levels of support, and 
3) Delays in the funding and development of new products, causing the overall 
selection and quality of software to suffer. 
THE DIFFERENT TYPES OF SOFTWARE PIRACY 
There are five basic forms of software piracy, and all are damaging both to the software publisher 
and to you, the end user. The five basic types of piracy are: 
• Soft lifting. This form of piracy occurs when extra copies of a program are made within an 
organization for employees to use. It also includes Disk swapping among friends and 
associates. 
• Hard-Disk Loading. Some computer dealers load unauthorized copies of software onto the 
hard disks of the computers they offer for sale, as an incentive for an end user to purchase a 
computer from that particular dealer. 
• Counterfeiting. This is the illegal duplication and sale of copyrighted software, often in a form 
designed to make the product appear legitimate. Software counterfeiting can be very 
sophisticated, including significant efforts to replicate packaging, logos, and anti-counterfeiting 
techniques such as holograms. It can also be unsophisticated, consisting of 
inferior or hand-written labels, with disks folded into a plastic bag and sold on street corners. A 
recent trend in counterfeiting is the emergence of compilation CD-ROMs, where numerous 
unauthorized software publishers’ programs appear on one CD-ROM. In any form, software 
counterfeiting is very damaging to both the software developer and legitimate end users. 
• Online. This form of piracy occurs when copyrighted software is downloaded to users 
connected through a modem to an electronic bulletin board or the Internet without the 
express permission of the copyright owner. This should not be confused with sharing public 
domain software or providing “shareware.” Shareware is software that may or may not be 
copyrighted but is generally offered for little or no charge by the author for nearly unrestricted 
use, including copying or sharing with others. Microsoft distributes promotional products, free 
software, updates, or enhancements over bulletin boards or online services, which may or may 
not be licensed for use solely with licensed Microsoft products. You should check the EULA 
accompanying the product to determine how it can be used. 
• License Misuse. This form of piracy occurs when copyrighted software is distributed outside the 
restricted legitimate channels it was designed for or the product is used in ways not allowed in 
the license agreement. Examples of license misuse include: 
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COMPUTER OPERATIONS  PACKAGES 
(1) Academic product misuse 
This form of license misuse occurs when a product that is manufactured, licensed, and 
specifically marked for distribution to educational institutions and students at reduced 
prices is diverted into normal commercial channels of distribution. Typically this 
product will contain a sticker indicating that it is academic product and for use only 
by educational institutions. 
(2) Not for Resale (NFR) product misuse. 
Again, this form of license misuse occurs when a product that has been clearly 
marked Not for Resale, and is typically distributed as a promotional or sample 
product and is not licensed for normal commercial distribution and use, is diverted into 
normal commercial channels of distribution. 
(3) Original equipment manufacturer (OEM) stand-alone product. This form of license 
misuse occurs when OEM version software has been unbundled from its designated 
computer system and distributed as a separate, “stand-alone” product. Microsoft’s 
agreement with computer manufacturers prohibits them from distributing Microsoft 
products in this fashion, i.e. without accompanying computer hardware. 
Microsoft products on the retail shelf should never include a line on the front cover of the 
User’s Guide that states, “For Distribution Only With New Computer Hardware.” 
(3) “Microsoft Easy Fulfillment” (MEF) product misuse. This form of license misuse occurs 
when a “Microsoft Easy Fulfillment” (MEF) product is diverted into normal commercial 
channels of distribution. The MEF product may be distributed only to end users who 
have a Select or Open (MOLP) license and who order the product in accordance with 
their license terms. The MEF product has a sticker on the jewel case identifying the 
product as “Microsoft Easy Fulfillment.” 
(4) Volume licensing misuse. Volume Licensing enables organizations to acquire the rights 
to copy and use specific Microsoft software products with agreements tailored to the 
number of products needed at the particular organization. These volume programs 
offer a broad range of products and licensing options and reduce administrative 
overhead and software management costs. 
Microsoft offers two types of volume license: 
a. Select provides savings for medium and large organizations with significant volume 
requirements through forecasting software needs over a two-year period. 
b. Open provides savings for small and medium organizations for licenses of as few as 20 
units of a particular software product, with a simple ordering process. 
Misuse under volume licensing occurs when organization copies software purchased 
through the volume program on more computers than specified in their license 
agreement. Other violations occur when an organization allows concurrent use of 
software products (which currently is offered only as an option under the Select and Open 
programs) without the purchase of the option that allows for this concurrent use. 
User licenses show users rights to use pieces of software. 
INTRODUCTION TO DATABASE SYSTEMS 
A DATABASE is a shared and integrated collection of logically related records or files consolidated 
into a common pool that provides data for one or more uses. 
 Is a collection of files? 
 An organized collection of interrelated files. 
 Is a collection of related files that provides a way of finding information quickly and easily 
from a chosen reference point? 
 Is an integrated collection of logically related records or files? 
 A database consolidates records previously stored in separate files into a common pool of 
data records that provides data for many applications. 
 Examples of databases are MS Access, MS Works Database, and DBaseIV, Oracle, SQL 
rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 80
COMPUTER OPERATIONS  PACKAGES 
Building Blocks of a Database System 
BIT  BYTE  FIELD  RECORD  FILE  DATABASE 
• A byte is also known as a character 
• A field is also known as a word 
• A file is also called a table or relation 
 File-Is a collection of related records. 
 Record-Is a collection of fields. It is a collection of fields arranged in a predefined 
rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 81 
order. 
 Field-Is a collection of single items. It is an implementation of the data attribute. It 
is the smallest unit of data to be stored in a database. 
 Primary key-Is a field whose value identifies one  only one record in a file. 
 Secondary key-An alternative index for identifying an entity. Its value can identify 
single entity occurrences of all entity occurrences. A subset of all entity 
occurrences. 
 Foreign key-Are pointers or links to occurrences of a different file. A foreign key in 
one file must be a primary key in another file. 
 Descriptors-Are any other fields that describe business entities. 
Traditional/Conventional/Flat Filing Systems 
• This is programming with files. Each user defines and implements the files needed for a 
specific application so that each application has its own separate data files and software 
programs 
• Although both users will be interested in the same data, each maintains separate files and 
programs to manipulate these files and this results in data redundancy and a lot other 
problems associated with it. 
Advantages of the Database Approach 
• Control over data redundancy 
• Increased data consistency/Reduced data confusion 
• Increased data integrity – concerned with validity and accuracy of data 
• Reduction in wastage of storage space 
• Program/Data independence 
• Increased productivity of application development 
• Improved data security 
• Data sharing 
Disadvantages 
• Database systems are complex, difficult and time consuming to design 
• There is greater impact of failure 
• Extensive conversion costs involved 
• Initial training is required for all users 
• Concurrence problems - where more than one user access and attempt to update the 
same record at the same time - there is file edit locking to prevent this. 
• Ownership problems - sometimes some individuals tend to own the data and thus refuse 
access by other individuals or departments in the organisation. 
• Resources problem - with database extra resources are needed e.g. more workstations 
and other devices. Substantial hardware and software startup costs are involved 
Security problems - there is increased exposure to unauthorised entry into the data. However, this 
could be reduced by the use of regularly changed passwords and by physically denying access to 
unauthorised users.
COMPUTER OPERATIONS  PACKAGES 
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DATABASE TERMINOLOGY 
• Entity - a real world object or event or anything that is capable of independence 
existence and about which we can collect information e.g. person, building, transaction, 
election 
• Attribute – a characteristic or property of an entity e.g. name 
• Primary key – an attribute that uniquely identifies an entity or record. A field that uniquely 
identifies a record in a table. In a students table, for instance, a key built from last name + 
first name might not give you a unique identifier (two or more Jane Does in the school, for 
example). To uniquely identify each student, you might add a special Student ID field to 
be used as the primary key. 
• Foreign key - A key used in one table to represent the value of a primary key in a related 
table. While primary keys must contain unique values, foreign keys may have duplicates. 
For instance, if we use student ID as the primary key in a Students table (each student has 
a unique ID), we could use student ID as a foreign key in a Courses table: as each student 
may do more than one course, the student ID field in the Courses table (often shortened to 
Courses.student ID) will hold duplicate values. 
• Normalization - The process of structuring data to minimise duplication and inconsistencies. 
The process usually involves breaking down a single table into two or more tables and 
defining relationships between those tables. The process of breaking up a table into 
multiple tables, each of which has a single theme, thereby reducing data redundancy; 2) 
The technique that reduces or eliminates the possibility that a database is subject to 
modification anomalies 
• Query - A view of your data showing information from one or more tables. For example, 
you could query a Students database asking Show me the first and last names of the 
students who take both history and geography and have Alice Hernandez as their 
advisor. Such a query displays information from the Students table (firstname, lastname), 
Courses table (course description) and Advisor table (advisor name), using the keys 
(student ID, course ID, advisor ID) to find matching information. Literally, a question you ask 
about data in the database in the form of a command, written in a query language, 
defining sort order and selection, that is used to generate an ad hoc list of records; 2) The 
output subset of data produced in response to a query. 
• SQL - Structured Query Language (pronounced sequel or ess-queue-ell). A computer 
language designed to organize and simplify the process of getting information out of a 
database in a usable form, and also used to reorganize data within databases. 
• Relation - A single store of related information. A table consists of records, and each 
record is made up of a number of fields. You can think of the phone book as a table: It 
contains a record for each telephone subscriber, and each subscriber’s details are 
contained in three fields – name, address and telephone. 
• DBMS - Database management system. A program which lets you manage information in 
databases. Microsoft Access is a DBMS, although the term is often shortened to 
‘database’. So, the same term is used to apply to the program you use to organize your 
data and the actual data structure you create with that program. 
• Domain - A collection or range of all the possible values a field can contain. Although a 
field’s domain is typically finite, it may be infinite as well. 
• Derived attribute - Synonymous with computed attribute, for which the value is calculated 
from those contained in other fields. Usually, computed fields’ values are calculated from 
other fields’ values that occur in the same record 
• Metadata - Data about data and the data’s structure within a database. Technical 
metadata reflects the description of the structure, content, keys, and indexes of data and 
their source of origin, while business metadata reflects definitions about measures (facts) 
using calculations 
• OLAP - (Online Analytical Processing)The OLAP Council defines online analytical processing 
as, A category of software technology that enables analysis, managers and executives to 
gain insight into data through fast, consistent, interactive access to wide variety of possible 
views of information that have been transformed from raw data to reflect the real 
dimensionality of the enterprise as understood by the user.
COMPUTER OPERATIONS  PACKAGES 
• Record - Synonymous with row and tuple. An instance of data in a table, a record is a 
collection of all the facts related to one physical or conceptual entity; often referring to a 
single object or person, usually represented as a row of data in a table, and sometimes 
referred to as a tuple in some, particularly older, database management systems. 
• Schema - The database’s metadata -- the structure of an entire database, which specifies, 
among other things, the tables, their fields, and their domains. In some database systems, 
the linking or join fields are also specified as part of the schema 
2) The description of a single table. Also called a Logical Schema. 
• Concatenated key – a key formed by joining two or more attributes 
• Relationship a link or association between any two entities in a database 
• ERD - An entity-relationship (ER) diagram is a specialized graphic that illustrates the 
interrelationships between entities in a database. ER diagrams often use symbols to 
represent three different types of information. Boxes are commonly used to represent 
entities. Diamonds are normally used to represent relationships and ovals are used to 
represent attributes. 
TYPES OF DATABASE RELATIONSHIPS 
One-to-One 
o Exactly one record in one table is related by a common linking field to exactly one record 
in another table, implying that each value of the linking field appears no more than once 
in each of the tables. Both tables can have only one record on either side of the 
relationship. Each primary key value relates to only one (or no) record in the related table. 
They're like spouses—you may or may not be married, but if you are, both you and your 
spouse have only one spouse. Most one-to-one relationships are forced by business rules 
and don't flow naturally from the data. In the absence of such a rule, you can usually 
combine both tables into one table without breaking any normalization rules. 
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One-to-Many 
o Exactly one record in one table is related by a common linking field to one or more 
records in another table, implying that each value of the linking field is unique in the first 
table, but not necessarily so in the second. The primary key table contains only one record 
that relates to none, one, or many records in the related table. This relationship is similar to 
the one between you and a parent. You have only one mother, but your mother may 
have several children. 
Many-to-Many 
• One or more records in one table may be related to one or more records in a second 
table by a common value or linking (join) field. This implies that each value of the linking 
field may appear any number of times in either or both tables. Each record in both tables 
can relate to any number of records (or no records) in the other table. For instance, if you 
have several siblings, so do your siblings (have many siblings). Many-to-many relationships 
require a third table, known as an associate or linking table, because relational systems 
can't directly accommodate the relationship. 
The Database Administrator 
This is a person responsible for planning, designing and maintaining the organisation's database. 
This person relates to the management, system analysts, programmers and other stakeholders in 
the organisation. He needs to have adequate managerial and technical abilities to suit the job. He 
therefore must have a sound knowledge of the structure of the database and the DBMS. 
Responsibilities of the Database Administrator (DBA) 
• Ensures that the database meets the needs of the organisation. 
• Ensures facilities for the recovery of data 
• Ensures the functioning of report generation systems form the DBMS 
• The DBA is also responsible for the documentation of the DBMS through the designing and 
availing of the data dictionary and manuals for the users giving such direction as the
COMPUTER OPERATIONS  PACKAGES 
general use of the database, access to information, deletion of records from the system 
and the general validation and verification of data. 
• The design of the database 
• After the initial design, the DBA must monitor the performance of the database, and if 
problems surface (such as a particular report taking an unacceptably long time to 
produce), appropriate changes must be made to the database structure. 
• Keeping users informed of changes in the database structure that will affect them; for 
example, if the size or format of a particular field is altered or additional fields added 
• Maintenance of the data dictionary for the database, and responsibility for establishing 
conventions for naming tables, columns, indexes  so on. 
• Implementing access privileges for all users of the database; that is, specifying which items 
can be accessed and / or changed by each user. 
• Allocating passwords to each user. 
• Providing training to users in how to access and use the database. 
• Manage the organizations 
• -data resources 
• -database plans 
• -design 
• -operations 
• -training 
• -user support 
• -security  Maintenance 
• Maintain data consistency and security 
• Approve access to data stored 
• Approve access procedures 
• ABILITY to delete, add, modify –existing data must be tightly controlled. 
Database Management System (DBMS) 
The DBMS is an application program that provides an interface between the operating system and 
the user in order to make access to the data as simple as possible. It has several other functions as 
well, and these are described below. 
1. Data storage, retrieval and update. The DBMS must allow users to store retrieve and update 
information as easily as possible, without having to be aware of the internal structure of the 
database. 
2. Creation and maintenance of the data dictionary 
3. Managing the facilities for sharing the database. The DBMS has to ensure that problems do 
not arise when two people simultaneously access a record and try to update it 
4. Back up and recovery. The DBMS must provide the ability to recover the database in the 
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event of system failure. 
5. Security. The DBMS must handle password allocation and checking, and the ‘view’ of the 
database that a given user is allowed. 
The data dictionary 
The data dictionary is a ‘database about the database’. A data dictionary, as defined in the IBM 
Dictionary of Computing, is a centralized repository of information about data such as meaning, 
relationships to other data, origin, usage, and format.[1] The term may have one of several closely 
related meanings pertaining to databases and database management systems (DBMS): 
• a document describing a database or collection of databases 
• an integral component of a DBMS that is required to determine its structure 
• a piece of middleware that extends or supplants the native data dictionary of a DBMS 
It will contain information such as: 
1. What tables and columns are included in the present structure? 
2. The names of the current tables and columns 
3. The characteristics of each item of data, such as its length and data type; 
4. Any restrictions on the value of certain columns
COMPUTER OPERATIONS  PACKAGES 
5. The meaning of any data fields that are not self-evident; for example, a field such as 
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‘course type’; 
6. The relationships between items of data 
7. Which programs access which items of data, and whether they merely read the data or 
change it? 
Advantages and any disadvantages of databases 
# ADVANTAGES # DISADVANTAGES 
1 Supports data sharing 1 Limitations of databases arise from increased 
technological complexity 
2 Ensures increased data security 2 Developing a large database and installing a 
DBMS can be difficult and expensive. 
3 Ensures data independence 3 More hardware capability is required, since 
storage requirements for the organization of 
data, overhead control data, and the DBMS is 
greater 
4 Data integrity is guaranteed. The functions in 
the DBMS can be used to enforce the integrity 
rules with minimum programming in the 
application programs. 
4 Problems of data inconsistency can arise if a 
distributed database approach is used. 
5 Reduces or minimizes data redundancy 5 Longer processing times may result from high 
volume transaction processing applications 
since extra layer software [the DBMS] exists 
between application programs and the 
Operating system. 
6 Consistence of data is ensured 
6 Security and integrity of data are major 
concerns. 
7 Support data integration. Since related data is 
stored in one single database, enforcing data 
integrity is much easier 
Centralized databases are vulnerable to errors, 
fraud and failures. 
8 Related data can be shared across programs 
since the data is stored in a centralized manner 
9 Enforcing of standards in the organization and 
structure of data files is required and also easy 
in a Database System, since it is one single set 
of programs, which is always interacting with 
data files 
10 The application programmer need not build the 
functions for handling issues like concurrent 
access, security, data integrity, etc. The 
programmer only needs to implement the 
application business rules. This brings in 
application development ease. 
Q* Limitations of file Processing Systems that the DBM system address 
i. Data duplication - Same kind of information is stored in several files 
ii. Lack of Data integration – Independent files make it difficult to provide end users with info 
for ad-hoc requests that require accessing data stored in different files 
iii. Data dependence – In a file processing system, the organization of files, their physical 
location on storage hardware and application software used to access those files depend 
on each other. 
Changes in format and structure o data and records in file require changes to all the 
programs 
Q* what is a DBMS (Data base Management System) 
Is a collection of software programs that: 
i. Stores data , in a uniform and consistent way 
ii. Organizes the data, into records in a uniform and consistent way 
iii. Allows access to the data, in a uniform and consistent way
COMPUTER OPERATIONS  PACKAGES 
	 A collection of software programs that stores organizes and allows access to the 
data in a uniform and consistent way 
	 Is a collection of programs that enables users to create and maintain a 
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database? 
	 A general purpose software system that facilitates the process of defining 
constructing and manipulating databases for various applications. 
Database Environment 
i. Database 
ii. Database users 
iii. DBM System 
iv. Data Dictionary 
v. Database Administrator 
vi. User/system interface 
Database Users 
i. Casual users 
ii. Naïve users – parametric users 
iii. Sophisticated end users 
I. Occasionally use it, and if they do a HLL such as AQL may be used. 
II. Those who use Standard queries and updates only e.g. bank cashiers, data entry 
clerks’ e.t.c. 
III. Know the whole range of facilities on a database environment. 
Q a. Explain the 3 Major disadvantages of a file system (6) 
b. Give and explain any 7 functions of a DBMSystem 
FUNCTIONS OF A Database Management SYSTEM 
1. Storage, Retrieval Update 
2. Catalogue 
3. Logical transactions 
4. Concurrency control 
5. Recovery 
6. Security 
7. Communications 
8. Integrity 
9. Data Independence 
10. Utilities 
1. Storage, Retrieval Update 
- Allows users with the ability to store, retrieve and update data in the database. 
2. Catalogue 
- Allows a catalogue in which descriptions of data items are stored and which is 
accessible to users 
3. Logical Transactions 
- Allows a mechanism which will ensure that either all of the updates corresponding 
to a given transaction are made or not made. .e.g. 
ABORT – ROLLBACK or undo all the changes 
COMMIT- Transaction gone thru and is already in the database. 
4. Concurrency Control 
- Allows a mechanism to ensure that the database is updated correctly when 
multiple users are updating the database concurrently 
LOCKING OR DEADLOCK situations must be avoided 
5. Recovery 
- Allows a mechanism for recovering the database in the event that the database 
is damaged in any way.
COMPUTER OPERATIONS  PACKAGES 
- A before / after image is usually created 
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6. Security 
- Allows a mechanism to ensure that only authorized users can access the 
database. 
- Authorizations, encryption features and limited views can be used as security 
provisions 
7. Communication 
- Must be capable of integrating with communications software on the database 
environment on a multi-user environment. 
8. Integrity 
- Allows a mechanism to ensure that both the data in the database and changes 
to the data follow certain rules. 
9. Data Independence 
- (Has facilities to) support the independence of programs from the actual structure 
of the database. 
10. Utilities 
- Provide a set of utility services e.g. optimized 
COMPONENTS OF A DBMS 
1. Data dictionary/directory 
2. Data language 
3. Application development tools 
4. Security software 
5. Report writers 
6. Query language 
7. Web server software 
8. Teleprocessing monitors 
9. Archiving, backup and Recovery systems 
1. DATA DICTIONARY/ DIRECTORY 
• Contains the names and descriptions of every data element in the 
database. 
• Also contains descriptions of how data elements relate to one another. 
• Ensures that data is stored in a uniform and consistent manner hence 
reducing redundancy. 
2. DATA LANGUAGES 
• Data description language (DDL) describes the characteristics of data elements. 
• DDL requires the application program to use standardized commands to retrieve and 
process data from a database. 
• Data manipulation language (DML) consists of commands such as FIND, GET, INSERT 
3. APPLICATION DEVELOPMENT TOOLS 
• A program designed to help programmers develop application programs that use the 
database e.g. CASE TOOLS 
4. SECURITY SOFTWARE 
• Provides a variety of tools to shield database from unauthorized access and from viruses 
5. REPORT WRITERS 
• Allows programmers, mgrs and others to design out put reports. 
6. QUERY LANGUAGE 
• A set of commands used primarily for accessing data from a database. 
• You can ask ad-hoc questions of the database interactively without the aid of 
programmers. 
• Examples SQL, NLQ, QBE. Structured Query language, Natural language Queries and 
Query by Example. 
7. WEB SERVER SOFTWARE 
• Turns the computer system housing database into a web server and enables users with 
web connection to access data from wherever they are located. 
• Also convert data into a format that is readable by standard browsers.
COMPUTER OPERATIONS  PACKAGES 
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8. TELEPROCCESSING MONITORS 
• A software package that manages communication between the database and remote 
terminals. 
9. ARCHIVING, BACK UP AND RECOVERY SYSTEMS 
• Provides the database manager with tools to make copies of the database. 
• Restart/ Recovery systems are tools used to restart the database and to recover lost data 
in the event of a failure. 
OBJECTIVES AND BENEFITS OF DATABASE APPROACH 
1. Data redundancy is reduced –reduces the duplication of data. 
2. Data inconsistence avoided. 
3. Sharing of data is promoted –since data is stored in centralized. 
4. Standards are enforced, thru the data dictionary /catalogue 
5. Base of application development /maintenance is available 
6. Uniform security/ privacy /integrity control s are applicable to group of users 
7. SECURITY – Passwords, access controls 
PRIVACY - Authorized users 
INTEGRITY – Accurate data 
8. Integration of data is achieved - since data is stored in one db 
9. Data independence is achieved/ observed - it is the immunity of applications to changes in 
storage structure and access strategy. 
10. Data accessibility and responsiveness. 
11. Structured Query Language e.g. select name from customer where town = Harare” 
RISK TO DATABASE APPROACH 
1. New, specialized personal 
2. Backup – important DBMS function (Recovery) 
3. Shared data – conflict and concurrency control 
4. Technological complexity 
5. Expensive to develop a large database and installing a DBMS can be difficult. 
6. More hardware capability is required – storage requirements overhead control data and 
the DBMS required more memory 
7. Problems of inconsistence can arise if a distributed data approach is used. 
8. Longer processing time may result from high volume transaction processing applications. 
9. Security and integrity are major concerns. 
10. Centralized database are vulnerable to errors fraud and failures. 
DATABASE MODELS OR TYPES OF DATABASES 
i) Hierarchical database model 
ii) Network database model 
iii) Relational database model 
iv) Object-oriented database model 
Hierarchical Database Model 
• It resembles an inverted tree structure, organogram or family tree. It reflects one-to-one 
(1:1) or one-to-many (1:M) relationships only among the records. 
• The uppermost record is called the root and from there data are organized into groups 
containing parent and child records(nodes) 
• A parent record is allowed to have one or more child records but a child node can have 
only one parent 
• Because relationships between data items follow clearly defined paths, access to data is 
fast 
• There is no relationship between brother or sister nodes 
• Each record is related to others in a parent-child relationship or tree structure.
COMPUTER OPERATIONS  PACKAGES 
• Relationships between among records form a hierarchy or tree structure. 
• The relationship among records is one to many since each data element is related only to 
DEPT 
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one element above it. 
• Searching a record involves moving progressively downward from a root and along the 
branches of the tree until the desired record is located. 
Diagram 
Network Database Model 
• Is almost similar to the hierarchical model but is more flexible and versatile because a 
record can be linked to any other record in the model; i.e. the network model can reflect 
a many-to-many (M:N) relationship. 
• The route to data is not necessarily downwards but can in any direction 
• The major advantage is its ability to handle sophisticated relationships among various 
records and more than one path can lead to desired data level 
• Network complexity limits users in their ability to access the database without the help of 
programming staff 
• A record can belong to a number of parents 
• Relationship among records is many to many 
• Allows entry into a database at multiple points because any data element or record can 
be related to many other data elements. 
• Permits a record to be a member of more than one set at a time Hierarchical and network 
models are less flexible than other database models because the relationship between 
records must be determined and implemented before a search can be conducted. 
Diagram 
Student 
Course
COMPUTER OPERATIONS  PACKAGES 
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Relational Database Model 
• Data elements are viewed as being stored in the form of tables(relations) 
• There are no pointers or links to talk about but the data is organized into two dimensional 
tables which are known as relations 
• Each table is composed of unique rows or records which are also known as tuples and 
each cell in the relation must be single valued 
• Relationships are either 1:1 or 1:M and in the case where M:N relationships exist junction 
tables are created All data elements within the database are viewed as being stored in 
the form of tables 
• Database Packages based on this structure link records in different or various tables to 
provide information to users as long as the share common data elements. 
• Data is organized in 2-dimensional tables. 
Diagram 
CUSTOMER 
CUSTOMER NO. CUSTOMER NAME CUSTOMER ADDRESS 
- - - 
- - - 
Object Oriented Model 
• Each object is bound together with its own data and a set of instructions that describe the 
behaviour and attributes of the object 
• The objects use messages to interact with one another e.g. the object building in a 
database can have the attributes: type, size, colour etc 
• This model uses objects and messages to accommodate new types of data and provide 
for advanced data handling 
 Each object in an object-oriented database model is bound together with its own data 
and a set of instructions that describe the behavior and attributes of the objects. 
 Objects use messages to interact with one another. 
 Every object is described by a set of attributes. 
 E.g. the object building in a database or architectural drawing may have the attributes 
TYPE, SIZE, COLOUR just as in any. 
 Every object must have a set of procedures or routines or a set of methods. 
 E.G methods for an architectural drawing might include instructions to display, rotate, or 
explode the drawing on a screen. 
FILE CONCEPTS 
The purpose of a computer file is to hold data required for providing information. A computer file is 
a collection of related records. Records consist of fields and the fields are made up of characters. 
A character is the smallest element of a file. A character may be a letter of the alphabet, a digit or 
of a special form (symbols). Logical files show what data items are contained and what processing 
may be done while physical files are viewed in terms of how data is stored on storage media. 
Types of Files 
a) Master Files 
They hold permanent data for use in applications such as stock control and credit 
control. Usually much of the data items in these files do not change frequently or with 
each transaction, e.g. name, address or date of birth. 
b) Transaction files
COMPUTER OPERATIONS  PACKAGES 
These are also called movement files. They hold temporary records of values. They are 
used to update the master file and are overwritten after the updating of the master file. 
Examples of Transaction files: 
• A customer order file or records, each of which has data on a particular order. 
• A time sheet data file that contains records, each of which has data on the 
number of hours worked by a particular employee. 
• A stock transaction file that contains records of stock additions or removals – 
one record for each movement. 
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c) Look up files 
They are reference files from which such information as prices list and mailing list can be 
obtained. 
d) Archive files 
These are files that are used to store information that has not been in use in the recent 
past and would not be in use in the near future – so are used to store historical data. 
e) Backup files 
These are copies of transaction files and master files held for security purposes 
f) Transition files 
Derived from a transaction file by the addition or deletion or ammendment of data. It is 
produced as a temporary file during data processing often by the addition of master 
file information to a transaction file prior to updating or output. Examples of transition 
files: 
• An employee time sheet transaction file which has had employee names 
added (from an employee master file) and re-sorted into department order 
• A customer order transaction file to which the price of each item ordered has 
been taken from a (computerised) catalogue and added 
FILE PROCESSING 
 Is the process of updating the records in a file to accurately reflect changes in the 
data? 
 It can be a manual process where procedures are in place to update forms, 
which are sent to the respective person responsible for the update. 
 It can also be a computerized process where information is first stored in 
transaction files until the master file is updated. 
File processing methods: 
1. BATCH PROCESSING is execution of a series of programs (jobs) on a computer without manual 
intervention. 
 Batch jobs are set up so they can be run to completion without manual 
intervention, so all input data is preselected through scripts or command-line 
parameters. This is in contrast to online or interactive programs which prompt the 
user for such input. A program takes a set of data files as input, process the data, 
and produces a set of output data files. This operating environment is termed as 
batch processing because the input data are collected into batches on files 
and are processed in batches by the program. Batch Processing 
 Transactions are collected and processed in batches [groups]. 
 Transaction processing in which transactions are gathered and stored for 
later execution. 
 E.g. a supermarket chain operates 5 outlets. At the end of the day all 
information on sales [transaction file] is collected,  the main records 
[master file] are updated with the sales for that day. 
 Performs a group of tasks all at once, while requiring little [or no] 
interaction with the user.
COMPUTER OPERATIONS  PACKAGES 
 It is a great time saver because the computer can perform repetitive 
functions quickly  consistently. 
Benefits 
Batch processing has these benefits: 
• It allows sharing of computer resources among many users and programs, 
• It shifts the time of job processing to when the computing resources are less busy, 
• It avoids idling the computing resources with minute-by-minute mannual intervention and 
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supervision, 
• By keeping high overall rate of utilization, it better amortizes the cost of a computer, 
especially an expensive one. 
COMMON BATCH PROCESSING USAGE 
• Data processing 
• A typical batch processing procedure is End of day-reporting (EOD), especially on 
mainframes. Historically systems were designed to have a batch window where online 
subsystems were turned off and system capacity was used to run jobs common to all data 
(accounts, users or customers) on a system. In a bank, for example, EOD jobs include 
interest calculation, generation of reports and data sets to other systems, print (statements) 
and payement processing. 
• Printing 
• A popular computerized batch processing procedure is printing. This normally involves the 
operator selecting the documents they need printed and indicating to the batch printing 
software when, where they should be output and priority of the print job. Then the job is 
sent to the print queue from where printing daemon sends them to the printer. 
• Databases 
• Batch processing is also used for efficient bulk database updates and automated 
transaction processing, as contrasted to interactive online transaction processing (OLTP) 
applications. 
• Images 
• Batch processing is often used to perform various operations with digital images. There exist 
computer programs like Batch Image Processor that let one resize, convert, watermark, or 
otherwise edit image files. 
• Converting 
• Batch processing is also used for converting a number of computer files from one format to 
another. This is to make files portable and versatile especially for proprietary and legacy 
files where viewers are not easy to come by. 
• Job scheduling 
• UNIX utilizes cron and at facilities to allow for scheduling of complex job scripts. Windows 
has a job scheduler. Most high-performance computingclusters use batch processing to 
maximize cluster usage. 
2. REAL-TIME PROCESSING, 
A real-time operating system (RTOS) OR REAL-TIME PROCESSING is a multitaskingoperating system 
intended for real-time applications. Such applications include embedded systems (programmable 
thermostats, household appliance controllers), industrial robots, spacecraft, industrial control (see 
SCADA), and scientific research equipment. 
A RTOS facilitates the creation of a real-time system, but does not guarantee the final result will be 
real-time; this requires correct development of the software. An RTOS does not necessarily have 
high throughput; rather, an RTOS provides facilities which, if used properly, guarantee deadlines 
can be met generally or deterministically (known as soft or hard real-time, respectively). An RTOS 
will typically use specialized scheduling algorithms in order to provide the real-time developer with 
the tools necessary to produce deterministic behavior in the final system. An RTOS is valued more 
for how quickly and/or predictably it can respond to a particular event than for the amount of 
work it can perform over a given period of time. Key factors in an RTOS are therefore a minimal 
interrupt latency and a minimal thread switching latency.
COMPUTER OPERATIONS  PACKAGES 
 An early example of a large-scale real-time operating system was Transaction 
Processing Facility developed by American Airlines and IBM for the Sabre Airline 
Reservations System. 
 Real-time Processing 
 The master records are updated as and when the transactions occur. 
 A form of transaction processing in which each transaction is executed as 
soon as complete data becomes available for the transaction. 
 A supermarket chain would be linked by a network to a main computer. 
 Each time a sale is made the stock information is updated and the sale 
information is also updated. 
 It is expensive and complicated. 
 Record and file locks are implemented to avoid problems with real-time 
processing. 
3. ONLINE PROCESSING, or OLP, refers to a class of systems that facilitate and manage transaction-oriented 
applications, typically for data entry and retrieval transaction processing. The term is 
somewhat ambiguous; some understand a transaction in the context of computer or database 
transactions, while others (such as the Transaction Processing Performance Council) define it in 
terms of business or commercial transactions. OLP has also been used to refer to processing in 
which the system responds immediately to user requests. An automatic teller machine (ATM) for a 
bank is an example of a commercial transaction processing application. 
 The technology is used in a number of industries, including banking, airlines, 
mailorder, supermarkets, and manufacturing. Applications include electronic 
banking, order processing, employee time clock systems, e-commerce, and 
eTrading. The most widely used OLP system is probably IBM'sCICS. 
 Online processing 
 A general term for when one computer is interacting directly and 
simultaneously with another computer. Many sources of information are 
available online. 
 Available for immediate use. 
 The master file is updated with the transactions through some form of 
communication link. 
 All real-time processing involves online processing. 
 Not all online processing needs to be real-time. 
 Require interaction of the user. 
Benefits 
Online Processing has two key benefits: simplicity and efficiency. Reduced paper trails and the 
faster, more accurate forecasts for revenues and expenses are both examples of how OLP makes 
things simpler for businesses. 
Disadvantages 
As with any information processing system, security and reliability are considerations. Online 
transaction systems are generally more susceptible to direct attack and abuse than their offline 
counterparts. When organizations choose to rely on OLP, operations can be severely impacted if 
the transaction system or database is unavailable due to data corruption, systems failure, or 
network availability issues. Additionally, like many modern online information technology solutions, 
some systems require offline maintenance which further affects the cost-benefit analysis. 
 Centralized processing 
 An information system where all critical data and programs are stored on 
one main computer, usually a mainframe. Unlike the task-sharing concept 
of a client/server system, the central computer retains all the brains and 
brawn. 
 A computing environment in which all processing takes place on a 
mainframe or central computer. 
 Puts all processing and control authority within one computer to which all 
other computing devices respond. 
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COMPUTER OPERATIONS  PACKAGES 
 Distributed Processing 
 The ability to have several computers working together in a network, 
where each processor runs different activities for a user, as required. 
 Computers connected together by a communications network. Data 
processing occurs on each of the computers, unlike a centralized 
processing system in which terminals are connected to a host computer 
that performs all of the data processing. 
 Use of computers at various locations, typically interconnected via 
communication links for the purpose of data access and/or transfer. 
 A computer system in which processing is performed by several separate 
computers linked by a communications network. The term often refers to 
any computer system supported by a network, but more properly refers to 
a system in which each computer is chosen to handle a specific 
workload, and the network supports the system as a whole. 
 Offline processing 
 When your computer performs an operation when it is not connected to 
any other computers, it is working offline. 
 Means that your computer is not currently connected to an Internet 
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server. 
 Not connected (to a network). Not available to the network 
 Time sharing 
 A way of sharing out computer facilities between a number of people 
who want to use the computer at the same time. Each has a separate 
terminal and gets the impression that they have sole use of the computer 
with their own 'account'. Similar to NETWORKING. 
 Transaction processing 
o A type of computer processing in which the computer responds immediately 
to User requests, with each User interaction considered to be a transaction. 
Automatic teller machines for banks are probably the best-known example. 
o In computer science, transaction processing is information processing that is 
divided into individual, indivisible operations, called transactions. Each 
transaction must succeed or fail as a complete unit; it cannot remain in an 
intermediate state. 
Master file is the main information source in any type of 
organization. 
File processing is the update of the master file [actual records] 
through manual or computerized methods.
COMPUTER OPERATIONS  PACKAGES 
FILE ORGANIZATION METHODS  ACCESS 
 File Organization-Is the arrangement of data records on storage media 
 It determines the manner in which individual records can be accessed or 
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retrieved 
Definitions of cycle time on the Web: 
• The time usually expressed in seconds for a controller to complete one on/off cycle. 
Definitions of access time on the Web: 
• The average time interval between a storage peripheral (usually a disk drive or 
semiconductor memory) receiving a request to read or write a certain location and 
returning the value read or completing the write. 
The amount of time it takes a computer to locate an area of memory for data storage or 
retrieval. 
• The time required to retrieve data from a storage device and transmit it to a specified 
location. 
Definitions of random access on the Web: 
• Storage systems where data may be stored and accessed in any order, independent of 
the ordinal position of the data when it was originally recorded. This is the opposite of linear 
(3) access, or linear recording media such as magnetic tape, which necessarily preserves 
the sequential relation of the data as it is recorded, and depends on this sequential 
relation for accurate playback. See non-linear recording. 
• Able to read any location directly; without having to read sequentially to the location. 
Definitions of sequential access on the Web: 
• Data must be read in the order it appears. This method applies to tape, and to a lesser 
degree to disks. 
Reading data from a file whose records are organized on the basis of their successive 
physical positions. To reach a specific record, all records previous to that record must be 
read, in order. Magnetic computer tapes are sequential access storage device. 
• Refers to reading or writing data records in sequential order, that is, one record after the 
other. To read record 10, for example, you would first need to read records 1 through 9. 
This differs from random access, in which you can read and write records in any order. 
TYPES OF QUERIES 
i. DIRECT QUERY 
ii. INVERTED QUERY 
i. DIRECT QUERY 
• Is one where the user can identify the entity in which he is interested? 
• He may want to know some of the particular of attributes of that entity. 
• e.g. Where a sales man wants to know the amount and location of a particular product in 
the organization. 
• He is able to identify the product by name or product number and this identification is 
used as the key for making the query which is also the primary record key. 
• The basic purpose of the direct query is to know the attribute values of already identified 
entities 
ii. INVERTED ENTITIES
COMPUTER OPERATIONS  PACKAGES 
• is one where the user does not know the identification of entities in which he is interested 
• he wants to identify the entities by some criteria or attribute values 
• e.g. the purchase department requiring a list of items for wh9ch the stock level is below the 
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desired level 
• in this case user does not know the identity of items already but want to know it 
• only specify a criterion as the basis of the query 
• Obviously the primary key cannot be used for retrieval, it is not available 
• Some attribute like stock level has to be used for the retrieval of records 
MODELS OF FILE ORGANISATION 
i. serial file organization 
ii. sequential file organization 
iii. indexed sequential file organization 
iv. direct file organization 
v. inverted file organization 
i. SERIAL FILE ORGANISATION 
• Is one where records are not stored in any particular order 
• They are stored in the order in which they are received 
• New records are added at the end of the files 
• This method of file organization is used when 
- the usage of the records is not clearly known 
- as a means of recording transaction as they happen 
- as dump files reflecting the physical layout of a file 
- as a prelude to organizing the file in another order i.e. transactions may be 
punched and stored on a serial file, the file may be subsequently be stored into a 
desired sequence 
- gives maximum utilization of space 
- no room is left for inserting other records 
- does not cater for direct access to records 
- used on magnetic tapes 
- popular on output files, archive files, security files 
i. SEQUENTIAL FILE ORGANISATION 
- records are arranged in a pre-determined sequence determined by the primary 
key 
- appropriate for files which are store on tape or disk 
- nor generally used for online system that demand fast response 
- mainly used for batch processing applications 
- suitable when there is for little file enquiry 
- can be used for variable length records as well as fixed length records 
- waste space as some space is left of reserved for other records to be inserted in 
order to preserve the order or organization 
 UPDATING 
 Updating on tape is carried out in batch mode by reading the whole file and 
rewriting it after necessary modification on to a new file. 
 On disk can be carried out without rewriting the whole file. 
 RETRIEVAL 
 Retrieval of a record from a sequential file on tape media can be made only in 
the sequential mode by reading all the records in sequence till the desired record 
is reached. 
 Retrieval of a record from a sequential file on direct access media (DISK) can be 
made by using sequential reach skip search, binary search. 
 HIT RATE
COMPUTER OPERATIONS  PACKAGES 
 In a batch processing run: The proportion of the number of records processed 
during a run to the total number of records on the file is called a hit rate. 
 The higher the volatility and the lower the frequency of updating,, the higher the 
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hit rate. 
 PROCESSING OF SEQUENTIAL FILES 
 Tapes provides for only serial access 
 Disks can be accessed in a serial order or random order. 
iii) INDEXED SEQUENTIAL FILES 
• Records are stored in sequence but in addition an index is provided to enable individual 
records to be located directly after reading the index. 
• Records are pointed to by indexes. 
• Used with disks only not with magnetic tapes. 
• Wastes space. 
• The index may be ignored and the data is read sequentially 
• The file may be accessed sequentially but using the index to skip over unwanted records 
=selective sequential access 
• Index may be read into memory and used to obtain data randomly. 
• Records can be accessed sequentially OR randomly. 
iv) DIRECT FILE ORGANISATION 
	 Files are stored or haphazardly and an address key is used as reference. 
	 Records are physically located at an address that is calculated from its primary 
key field. 
	 The calculation of the address from the key field is called hashing. 
	 Records are scattered on the storage disk instead of being arranged next to one 
another or linked via a pointer field. 
	 Records can rapidly be retrieved and accessed directly 
	 Used on magnetic disks (e.g. floppies, hard disk) and optical disks. 
	 Costly in terms of device used and space. 
v) INVERTED FILE ORGANISATION 
	 special case of indexed sequential organization 
	 an index is maintained for every attribute in the record 
	 the main file itself may not be stored if direct queries are not to be handled 
	 the entire file data is, in any case, stored in the indexes 
	 Useful for handling inverted queries. 
vi) MULTI-RING FILE ORGANISATION 
	 useful for handling inverted query when sets of records have same attribute value 
	 Each set of records with same attribute values is linked into a ring. 
	 A ring of records is a chain where the last in the chain points to the first. 
	 One of the records is anchored to the index so that it provides an entry point into 
the ring. 
	 The index of the attribute is read first to retrieve records with a particular attribute 
value. 
	 All records with that attribute value can be located. 
COMPUTER MEMORY 
RAM (Random Access Memory) 
Also referred to as Main Memory, Primary Memory or Working Memory is memory that is 
accessed by the CPU as it processes information. The CPU also places results of processing 
on the memory chip. The memory has the following characteristics. 
1) can be read from 
2) can be changed and can be rewritten 
3) used for short-term storage of data i.e. it is temporary storage,
COMPUTER OPERATIONS  PACKAGES 
4) is volatile (data lost when power is turned off). 
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Types of RAM 
• DRAM (Dynamic RAM) This is the most common type of computer memory. DRAM needs 
refreshing and is refreshed hundreds of times each second in order to retain data. During 
recharging it cannot be accessed by the CPS 
• SRAM (Static RAM) SRAM is approximately 5 times faster (and twice as expensive, as 
DRAM). It does not have to be constantly refreshed. Because of its lower cost and smaller 
size, DRAM is preferred for the main memory, while SRAM is used primarily for cache 
memory. 
• SDRAM (synchronous dynamic RAM) is the standard memory offering in the PC industry 
and is faster than DRAM because it's synchronized to the system clock. . It is designed for 
mainstream home and business applications, email, and basic audio and video streaming. 
It provides single-channel memory and is available on our mainstream and value desktop 
system. 
• DDR SDRAM (double data rate synchronous dynamic RAM) takes all the features of 
ordinary SDRAM and increases the frequency bandwidth to improve system performance 
and speed. 
• RDRAM (Rambus dynamic RAM) is able to load a new stream of data before the previous 
stream has completed, resulting in faster access speeds. The RDRAM memory features 
dual-channel processing which doubles data throughput to further enhance 
performance. This type of memory is optimized for high-end multimedia tasks involving 
video and audio. Dual Channel RDRAM is shipped on our performance desktop systems 
powered by Pentium 4 processors 
• VRAM: Memory designed for storing the image to be displayed. 
• CACHE RAM is a small block of high-speed memory located between the Processor and 
main memory and is used to store frequently requested data and instructions. When the 
processor requests data, it will check in the cache first 
The computer has two types of memory chips within the system unit, known as RAM and 
ROM. 
ROM (Read Only Memory) 
This memory chip has essential programs that start up the computer hardwired on the 
microchip during the manufacture of the computer. It forms what is known as FIRMWARE, 
being a halfway between hardware and software. The characteristics of this memory are 
that:- 
1) can be read from, 
2) cannot be changed 
3) is permanent 
4) non-volatile (data not lost when power is turned off). 
 ROM 
 Stores instructions  data which do not change 
 It is written once during manufacture 
 It is for holding software such as MS-DOS.Windows 95, 98.XP. 
 It is programmed by the manufacturer and cannot be altered by the user 
 It is static  non volatile 
 It stores control routines for personal computers 
VARIATIONS OF ROM 
Allow users to store and in some cases to change data stored in ROM 
 PROM [Programmable ROM] is not programmed during manufacture but can be 
programmed by the user. It is programmed according to the needs of the user 
organization. If you make a mistake the ROM once programmed will became 
permanent to the effect that any errors will never be corrected thus the user will 
throw away any chip if errors are made.
COMPUTER OPERATIONS  PACKAGES 
 EPROM [Erasable Programmable ROM] can be programmed and erased as many 
times. This time you don’t have to worry about errors too much because there is 
room for correction. The programming is done electronically. Stored data can be 
lost by exposing it to Ultra Violet light over a period of minutes. 
1) EEPROM [Electrically Erasable Programmable ROM] can be read, erased, 
rewritten, without removing from the computer. The erasing  rewriting process is 
very slow compared with reading, which limits their use. These can be erased  
programmed with electrical pulses. Can be erased in a few Milliseconds 
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MEMORY CAPACITY 
Everything entering into the computer is converted into digital (number) form, and is stored 
in that form. When one needs to view the information, it is converted into human sensible 
text, graphics, audio or video by the operating system. A binary digit is known as a bit 
being either a ‘0’(zero) or a ‘1’(one). It is the smallest item that can be stored in a 
computer’s memory. 
Memory capacity is measured in bytes, a byte being a set of eight(8) bits and the byte often 
represents a single character. Measurement units used for computer memory are:- 
o BIT 1 binary digit (Either a 0 or a 1) 
o BYTE Eight bits. 
o NIBBLE Half byte/4 bits 
o KILOBYTE (KB) 1024 bytes 
o MEGABYTE (MB) Million bytes 
o GIGABYTE (GB) Billion bytes 
o TERABYTE Trillion bytes 
NETWORKS 
 A computer network, often simply referred to as a network, is a collection of computers 
and other hardware components interconnected by communication channels that allow 
sharing of resources and information Where at least one process in one device is able to 
send/receive data to/from at least one process residing in a remote device, then the two 
devices are said to be in a network. Simply, more than one computer interconnected 
through a communication medium for information interchange is called a computer 
network. 
 Networks may be classified according to a wide variety of characteristics, such as the 
medium used to transport the data, communications protocol used, scale, topology, and 
organizational scope. 
 Communications protocols define the rules and data formats for exchanging information 
in a computer network, and provide the basis for network programming. Well-known 
communications protocols include Ethernet, a hardware and link layer standard that is 
ubiquitous in local area networks, and the Internet protocol suite, which defines a set of 
protocols for internetworking, i.e. for data communication between multiple networks, as 
well as host-to-host data transfer, and application-specific data transmission formats. 
 Computer networking is sometimes considered a sub-discipline of electrical engineering, 
telecommunications, computer science, information technology or computer 
engineering, since it relies upon the theoretical and practical application of these 
disciplines. 
Properties 
Computer networks: 
1. Facilitate communications 
Using a network, people can communicate efficiently and easily via email, instant 
messaging, chat rooms, telephone, video telephone calls, and video conferencing. 
2. Permit sharing of files, data, and other types of information
COMPUTER OPERATIONS  PACKAGES 
In a network environment, authorized users may access data and information stored on 
other computers on the network. The capability of providing access to data and 
information on shared storage devices is an important feature of many networks. 
3. Share network and computing resources 
In a networked environment, each computer on a network may access and use resources 
provided by devices on the network, such as printing a document on a shared network 
printer. Distributed computing uses computing resources across a network to accomplish 
tasks. 
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4. May be insecure 
A computer network may be used by computer hackers to deploy computer viruses or 
computer worms on devices connected to the network, or to prevent these devices from 
normally accessing the network (denial of service). 
5. May interfere with other technologies 
Power line communication strongly disturbs certain forms of radio communication, e.g., 
amateur radio. It may also interfere with last mile access technologies such as ADSL and 
VDSL. 
6. May be difficult to set up 
A complex computer network may be difficult to set up. It may also be very costly to set 
up an effective computer network in a large organization or company. 
NETWORK TOPOLOGIES 
A network topology is the arrangement of elements (such as data links or nodes) in a network. It is 
the physical arrangement of terminals in a local area network. The choice of topology is 
dependent upon 
• type and number of equipment being used 
• planned applications and rate of data transfers 
• required response times 
• cost 
Definitions of hub on the Web: 
 A common connection point for devices in a network. Hubs are commonly used to 
connect segments of a LAN. A hub contains multiple ports. When a packet arrives at one 
port, it is copied to the other ports so that all segments of the LAN can see all packets. A 
passive hub serves simply as a conduit for the data, enabling it to go from one device (or 
segment) to another. ... 
 Node – a terminal point in a communications network. 
 Workstation – A computer terminal or micro- or minicomputer system designed to support 
the work of one person. 
MESH TOPOLOGY 
Mesh topology work on the concept of routes. In Mesh topology, message sent to the destination 
can take any possible shortest, easiest route to reach its destination. In the previous topologies star 
and bus, messages are usually broadcasted to every computer, especially in bus topology. 
Similarly in the Ring topology message can travel in only one direction i.e clockwise or 
anticlockwise. Internet employs the Mesh topology and the message finds its route for its 
destination. Router works in find the routes for the messages and in reaching them to their 
destinations. The topology in which every devices connects to every other device is called a full 
Mesh topology unlike in the partial mesh in which every device is indirectly connected to the other 
devices.
COMPUTER OPERATIONS  PACKAGES 
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STAR TOPOLOGY 
 Is a network in which nodes are connected to a central component as its hub? 
 The central component can be a switching device like a switch or PABX [private 
automatic branch exchange], a computer [minicomputer to which workstations 
or PCs are connected] or just a wiring center that is a common termination point 
for the nodes, called a hub. 
 A HUB is a component that serves as a common termination point for multiple 
nodes and that can relay [store  forward] signals along the appropriate paths. 
Definitions of star network on the Web: 
• A network in which all terminals are connected through a single point, such as a star 
coupler. 
• A network topology in the form of a star. At the center of the star is a wiring hub or 
concentrator, and the nodes or workstations are arranged around the central point 
representing the points of the star. 
Advantages of star topology 
 It is easy to add or remove nodes 
 Because each node has its own link to the central node, the star is more reliable than 
other topologies. 
 Full utilization of resources i.e. printer, sharing of processor 
 Direct connection of terminals to the main processor, means that if one terminal breaks 
down it wont affect other terminals. 
Disadvantages of star topology
COMPUTER OPERATIONS  PACKAGES 
 All traffic between two nodes passes through the central node. If the central component 
breaks down, the whole network is down. 
 The number of ports of the central component limits the number of connected nodes. 
 A star topology requires a lot of cabling since all data path connections must be to the 
central node. 
 There is no direct communication between or among workstations 
 Sharing of processor delays in the processing of jobs. 
BUS/LINEAR TOPOLOGY 
 
Describes a network in which each n 
 This is also sometimes called a horizontal, multidrop or multi point network. 
 Though it is preferable to use the last terms for connections with a mainframe/mini 
computer as in the following diagram. 
 In a bus messages 
nodes but every node can hear each message as it goes past. 
 When the signal/message reaches an end of the bus, a terminator absorbs it, to 
keep it from traveling back again along the bus line, 
other messages already in the line. 
 The data/signals/messages are transmitted in packets along the bus. 
 Each packet is send with a receiver identification code 
destination and all computers on the network ar 
messages coming to them. 
Definitions of bus network on the Web: 
• A single-cable LAN, in which all computers on the network are connected in series to a 
single cable. On a bus network, each computer hears all of the transmi 
the line, and selects only those that are addressed to its location. This is the simplest and 
most common LAN technology. 
Advantages of Bus Network/topology 
 When a node breaks down, the network does not break down. 
 A bus uses relatively 
 Direct communication due to direct connection. 
 Fast processing since there is no Host computer 
 Once a cable has been laid down any new equipment can easily be 
connected to the network by a simple tapping into the c 
Disadvantages of Bus Network/topology 
 In a bus topology it is not always easy to add a node. [E.g. installation of extra tap in thick 
Ethernet]. 
 Diagnosis/trouble shooting can be difficult. 
 Expensive to run [several processors] 
 Communication between components of the network traveling in opposite direction 
along the bus can collide 
rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 
s node is connected to a common line. 
travel in both directions and do not go through the individual 
to avoid interference with 
that is an address of 
are permanently on the alert for any 
transmissions going down 
less cables compared to other topologies 
cable. 
– Detectors. 
tion causing loss of transmitted information. 
102 
ode e ssions able.
COMPUTER OPERATIONS  PACKAGES 
 Because of this collision a detection system has to be present to control the re 
of lost information thereby making it a more expensive option 
RING NETWORK 
eby  A ring network has nodes connected in a circular way. 
 Each node has two neighboring nodes 
 Data flow is unidirectional. 
 A message is forwarded in one direction until it reaches the destination with 
intermediate nodes acting as relay [store  forward] units. 
 The destination node copies the message and passes the message again to the 
ring. 
 This message then continues to circulate around the ring back to the source. 
Definitions of ring network on the 
Web: 
• A network topology in the form of a closed loop or circle. Each node in the network is 
connected to the next, and messages move in one direction around the system. When a 
message arrives at a node, the node examines the address information in the mess 
the address matches the node's address, the message is accepted; otherwise the node 
regenerates the signal and places the message back on the network for the next node in 
the system. ... 
Advantages of ring network 
 The message return provides the 
The node removes its own message from the ring. 
 Little cabling needed compared to Star. 
 Each node acts as relay unit. 
 Packet collisions do not occur because information is traveling in one 
direction. 
 Relatively cheap 
 Efficient and accurate means of communication. 
 There is no dependency on the host computer or file server as each node 
controls transmission to and from itself. 
Disadvantages of ring network 
 Adding or removing nodes disrupts the network. 
 If one of the nodes breaks down, the whole network will be down. 
 If the network cable breaks the whole network is affected 
rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 
source with a form of acknowledgement. 
to install. 
103 
re-transmission 
message. If
COMPUTER OPERATIONS  PACKAGES 
rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 104 
TREE TOPOLOGY 
Tree topologies are comprised of the multiple star topologies on a bus. Tree topologies integrate 
multiple star topologies together onto a bus. Only the hub devices can connect directly with the 
tree bus and each Hub functions as a root of a tree of the network devices. This bus/star/hybrid 
combination supports future expandability of the computer networks, much better than a bus or 
star. 
Advantages of a Tree Topology 
• Point-to-point wiring for individual segments. 
• Supported by several hardware and software venders. 
Disadvantages of a Tree Topology 
• Overall length of each segment is limited by the type of cabling used. 
• If the backbone line breaks, the entire segment goes down. 
• More difficult to configure and wire than other topologies. 
LANs and WANs 
There are two types of network: LAN and WAN. 
LAN (LOCAL AREA NETWORK) 
A LAN is a high-speed data network that covers a relatively small geographic area. It typically 
connects workstations, personal computers, printers, servers, and other devices. LANs offer
COMPUTER OPERATIONS  PACKAGES 
computer users many advantages, including shared access to devices and ap 
exchange between connected users, and communication between users via electronic mail and 
other applications. The development of standard networking protocols and media has resulted in 
worldwide proliferation of LANs throughout business an 
 Typically connects computer in a single building or campus. 
 Developed in 1970s. 
 Medium : optical fibres, 
 Low latency (except in high traffic periods). 
 High speed networks (0.2 to 100 Mb/sec). 
 Speeds adequate for most distr 
 Problems : Multimedia based applications 
 Typically buses or rings. 
 Ethernet, Token Ring 
A LAN is a Local Area Network covering a small area such as one building e.g. in a school or a 
college. 
WAN (WIDE AREA NETWORK) 
A network consisting of computers of LAN's connected across a distance WAN can cover small to 
large distances, using different topologies such as telephone lines, fiber optic cabling, satellite 
transmissions and microwave transmissions 
geographic areas. Dedicated transoceanic cabling or satellite uplinks may be used to connect 
this type of network. Using a WAN, schools in Harare can communicate with places like Pretoria in 
a matter of minutes, without paying enormous phone bills. A WAN is complicated. It uses 
multiplexers to connect local and metropolitan networks to global communications networks like 
the Internet. To users, however, a WAN will not appear to be much different than a LAN or a MAN. 
 Developed in 1960s. 
 Generally covers large distances (states, countries, continents). 
 Medium: communication circuits connected by 
 Routers forwards packets from one to another following a route from the sender to the 
receiver. Store-and-Forward 
 Hosts are typically connected (or close to) the routers. 
 Typical latencies : 100ms 
 Problems with delays if using 
 Typical speed: 20 - 2000 Kbits/s. 
 Not (yet) suitable for distributed computing. 
 New standards are changing the landscape. 
A WAN is a Wide Area Network coverin 
rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 
applications, file 
and educational organizations. 
, coaxial cables, twisted pair, wireless. 
distributed systems 
transmissions. Wide Area Networks (WANs) connect larger 
ithout routers. 
- 500ms. 
satellites. 
covering a large geographical area. 
105 
plications, .
COMPUTER OPERATIONS  PACKAGES 
Advantages and disadvantages of networks 
ADVANTAGES OF GROUP WORKING  SHARING RESOURCES OVER A NETWORK. 
ADVANTAGES OF INSTALLING A NETWORK 
1. Speed. Networks provide a very rapid method for sharing and transferring files. Without a 
network, copying them to floppy disks, then carrying or sending the disks from one 
computer to another shares files. This method of transferring files (referred to as sneaker-net) 
is very time-consuming. 
2. Cost. Networkable versions of many popular software programs are available at 
considerable savings when compared to buying individually licensed copies. Besides 
monetary savings, sharing a program on a network allows for easier upgrading of the 
program. The changes have to be done only once, on the file server, instead of on all the 
individual workstations. Low cost. Single device shared by several machines reduce the 
need to buy many peripheral devices. Resource sharing also serves money. An installation 
can have several low-cost work stations accessing a single file-server. That puts a lot of 
processing power on the user’s desk without the expense of large mainframe systems. 
3. Security. Files and programs on a network can be designated as copy inhibit, so that you 
do not have to worry about illegal copying of programs. Also, passwords can be 
established for specific directories to restrict access to authorized users. Security is good - 
users cannot see other users' files unlike on stand-alone machines. 
4. Centralized Software Management. One of the greatest benefits of installing a network at 
a school is the fact that all of the software can be loaded on one computer (the file 
server). This eliminates that need to spend time and energy installing updates and tracking 
files on independent computers throughout the building. Site licenses are likely to be 
cheaper than buying several stand-alone licenses. 
5. Resource Sharing. Sharing resources is another area in which a network exceeds stand-alone 
computers. Some organizations cannot afford enough laser printers, fax machines, 
modems, scanners, and CD-ROM players for each computer. However, if these or similar 
peripherals are added to a network, they can be shared by many users. Resource sharing 
is the primary benefit of networking. It allows users on different machines to share modems, 
printers, tape drives and disk space, for example, users can send network messages 
requesting to use a central printer, allowing everyone to share that resource. Users realize 
the benefit of sharing information. Data files can be shared between machines on the 
network, allowing users to see invoices, results of surveys, company newsletters, and other 
information. 
6. Electronic Mail. The presence of a network provides the hardware necessary to install an 
e-mail system. E-mail aids in personal and professional communication for all school 
personnel, and it facilitates the dissemination of general information to the entire school 
staff. Electronic mail on a LAN can enable students to communicate with teachers and 
peers at their own school. If the LAN is connected to the Internet, students can 
communicate with others throughout the world. 
7. Flexible Access. Networks allow data  information access from any computer in the 
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campus. 
8. Workgroup Computing. Workgroup software (such as Microsoft BackOffice) allows many 
users to work on a document or project concurrently. For example, educators located at 
various schools within a county could simultaneously contribute their ideas about new 
curriculum standards to the same document and spreadsheets. 
9. It turns isolated computers into integrated systems, providing an environment where 
resources are shared and capacity problems reduced.
COMPUTER OPERATIONS  PACKAGES 
10. It allows growth. If more computing resources become a need, a new computer can be 
installed, added to the network, and immediately accessed by other machines and users. 
11. High reliability. If applications share data, the data can be replicated across several 
machines. If one machine goes down, another can take its place and provide the data to 
the applications. 
12. A file server is easy to back up as all the data is stored in one place 
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DISADVANTAGES 
Disadvantages of Installing a Network 
1. Expensive to Install. Although a network will generally save money over time, the initial 
costs of installation can be prohibitive. Cables, network cards, and software are 
expensive, and the installation may require the services of a technician. Purchasing the 
network cabling and file servers can be expensive. 
2. Requires Administrative Time. Proper maintenance of a network requires considerable 
time and expertise. Many organizations have installed a network, only to find that they did 
not budget for the necessary administrative support. 
Increased administration. There will be need for a systems administrator to tune the 
network, monitor the network, administer database files, and ensure network integrity 
(ensure the network runs smoothly) 
3. File Server May Fail. Although a file server is no more susceptible to failure than any other 
computer, when the files server goes down, the entire network may come to a halt. 
When this happens, the entire school may lose access to necessary programs and files. 
4. Cables May Break. Some of the configurations are designed to minimize the 
inconvenience of a broken cable; with other configurations, one broken cable can stop 
the entire network. 
5. Security concerns. Some user can gain unauthorized access to private data. There is a 
danger of hacking, particularly with wide area networks. Security procedures are needed 
to prevent such abuse. Of all the disadvantages, the greatest drawback is security 
concerns; therefore, network security is a priority in the development of network 
applications. 
6. Network failure. As applications increase their use of a network, network failures become 
catastrophic. 
7. Virus attack. A networked system is vulnerable to destructive network messages. For 
example, a message that sparks damaging activity (like erasing files) may enter the 
system via the network.Viruses can spread to other computers throughout a computer 
network. 
8. Managing a large network is complicated, requires training and a network manager 
usually needs to be employed. 
9. If the file server breaks down the files on the file server become inaccessible. E-mail might 
still work if it is on a separate server. The computers can still be used as stand alones. 
Network Security 
The field of network security in general and of TCP/IP security in particular is too wide to be dealt 
with we take the most common security exposures and measures to counteract them. Because 
many, if not all, security solutions are based on cryptographic algorithms. 
Security Issues 
This section gives an overview of some of the most common attacks on computer security, and it 
presents viable solutions to those exposures and lists actual implementations.
COMPUTER OPERATIONS  PACKAGES 
Common Attacks 
For thousands of years, people have been guarding the gates to where they store their treasures 
and assets. Failure to do so usually resulted in being robbed, neglected by society or even killed. 
Though things are usually not as dramatic anymore, they can still become very bad. Modern day 
I/T managers have realized that it is equally important to protect their communications networks 
against intruders and saboteurs from both inside and outside. We do not have to be overly 
paranoid to find some good reasons why this is the case: 
 Tapping the wire: to get access to clear text data and passwords 
 Impersonation: to get unauthorized access to data or to create unauthorized e-mails, 
rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 108 
orders, etc. 
 Denial-of-service: to render network resources non-functional 
 Replay of messages: to get access to and change information in transit 
 Guessing of passwords: to get access to information and services that would normally be 
denied. 
 Guessing of keys: to get access to encrypted data and passwords (brute-force attack, 
chosen cipher text attack, chosen plaintext attack) 
 Viruses, Trojan horses and logic bombs: to destroy data 
Though these attacks are not exclusively specific to TCP/IP networks, they should be considered 
potential threats to anyone who is going to base his/her network on TCP/IP, which is what the 
majority of enterprises, organizations and small businesses around the world are doing today. 
Hackers (more precisely, crackers) do likewise and hence find easy prey. 
Observing the Basics 
Before even thinking about implementing advanced security techniques such as 
the ones mentioned in the following sections, you should make sure that basic 
security rules are in place: 
 Passwords: Make sure that passwords are enforced to be of a minimum length (typically six to 
eight characters), to contain at least one numeric character, to be different from the user ID 
to which they belong, and to be changed at least once every two months. 
 User IDs: Make sure that every user has a password and that users are locked out after several 
logon attempts with wrong passwords (typically five attempts). Keep the passwords to 
superuser accounts (root, supervisor, administrator,etc.) among a very limited circle of trusted 
system, network and security administrators. 
 System defaults: Make sure that default user IDs are either disabled or have passwords that 
adhere to the minimum requirements stated above. Likewise, make sure that only those 
services are enabled that are required for a system to fulfill its designated role. 
 Physical access: Make sure that access to the locations where your systems and users 
physically reside is controlled appropriately. Information security begins at the receptionist, not 
at the corporate firewall. 
 Help desk: Make sure that callers are properly identified by help desk representatives or system 
administrators before they give out forgotten passwords or user IDs. Social engineering is 
often the first step to attack a computer network. 
Solutions to Security Issues 
Therefore, a combination of several such solutions should be considered in order to guarantee a 
certain level of safety and security. 
 Encryption: to protect data and passwords 
 Authentication and authorization: to prevent improper access 
 Integrity checking and message authentication codes (MACs): to protect against the 
improper alteration of messages
COMPUTER OPERATIONS  PACKAGES 
 Non-repudiation: to make sure that an action cannot be denied by the person who 
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performed it 
 Digital signatures and certificates: to ascertain a party's identity 
 One-time passwords and two-way random number handshakes: to mutually authenticate 
parties of a conversation 
 Frequent key refresh, strong keys and prevention of deriving future keys: to protect against 
breaking of keys (crypto-analysis) 
 Address concealment: to protect against denial-of-service attacks 
 Content inspection: to check application-level data for malicious content before 
delivering it into the secure network 
What is the Internet? 
 The Internet is the network of networks being a worldwide collection of computers that 
communicate with one another over cables, satellites and optical fibers. It is literally the 
whole hardware mass. The Internet is the network used to transport information. 
Internet, by definition is a network of networks that interact with each other through exchange 
of data packets. The Internet hosts an enormous information base and carries numerous 
information resources and services.. 
 When we refer to the Internet we are usually talking about the World Wide Web (WWW) 
which is the most used feature of the Internet. 
 The WWW stores millions of web pages on web servers. These pages can contain text, 
pictures, movies, animation and sound. Web pages are written in a language or code 
called HTML (Hypertext Markup Language). A set of web pages is called a website. 
 Each web page has its own unique address or URL. The URL will have the format http and 
a domain (such as .co.uk). What goes in between is arbitrary, but often has the term 
www such as in http://www.name.co.uk. but it doesn’t have to (e.g. 
http://news.bbc.co.uk). 
 Most sites have a page that links the user to the other main areas of the site. This is called 
the homepage. 
 Web pages are connected by hypertext links. When a link is clicked you will be taken to 
another page which could be on another server in any part of the world. 
 When you move around web pages you are said to be surfing the net. For this you need a 
program to read the pages (called a browser), such as Firefox or Internet Explorer. 
 To search for a particular item or topic on the net you use a search engine. There are 
many different kinds of search engine, each using slightly different ways of searching and 
indexing web content. Google, MSN and Alta Vista are all examples of search engines, 
while Yahoo and Excite are web directories (a bit like the Yellow Pages phone book) which 
have a search function built in. 
 The World Wide Web Is software that runs on the internet which includes all documentation 
that is shared and accessed on the internet. 
 A Web page is a document designed to be accessed and read over the WWW. It must 
have an address in a recognized format. 
DEFINITION OF TERMS 
ISPs (Internet Service Providers) 
• An ISP is a company that provides access to the Internet to individuals or companies. ISPs 
provide local dial-up access from your personal computer to their computer network and 
their network connects you to the Internet. 
• An institution (usually a private company) that provides access to the Internet in some 
form, usually for money. 
• A business that delivers access to the Internet.
COMPUTER OPERATIONS  PACKAGES 
• Are the companies who provide you with access to the internet. Commonly used ISPs in 
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Zimbabwe are: 
1. PowerTel 
2. ZOL 
3. Africom 
4. Ecoweb 
5. Telecel 
6. Comone 
7. BSAT 
8. Brodacom 
9. Mweb 
Most offer the same basic package of Internet access, email addresses, web space for your own 
pages and local rate call charges. 
Browser or web browser 
• A web browser is a software application that enables a user to display and interact with 
HTML documents hosted by web servers or held in a file system. Popular browsers 
available for personal computers include Microsoft Internet Explorer, Mozilla Firefox, 
Opera, and Safari. A browser is the most commonly used kind of user agent. The largest 
networked collection of linked documents is known as the World Wide Web. 
• Is a program that allows you to view the pages on the Web? The most widely used are 
1. Internet Explorer 
2. Mozilla Firefox 
3. Google chrome 
4. Opera 
5. Safari 
All browsers will have a number of similar features to help you use the Web: 
• Forward and back buttons to move between pages 
• A history folder which stores details of recently visited web pages 
• A stop button if a page is taking too long to load 
• Favorites and bookmark options to store often visited pages 
• Options to cut, copy, save and print the information viewed 
Search engines 
• Internet search engines help users find web pages on a given subject. The search engines 
maintain databases of web sites and use programs (often referred to as spiders or robots) to 
collect information, which is then indexed by the search engine. Similar services are provided 
by directories, which maintain ordered lists of websites, eg Yahoo! 
• Examples of search engines are: Google, MSN, Bing, Yahoo, AltaVista 
Internet address 
• The numbering system used in TCP/IP internetwork communications to specify a particular 
network or a particular host on that network with which to communicate. Internet addresses 
are commonly denoted in dotted decimal form. 
Examples of internet addresses 
1. www.facebook.com 
2. www.google.com 
3. www.yahoo.com 
4. www.gmail.com 
5. www.herald.co.zw 
• An IP address (Internet Protocol address) is a unique number, a kind of telephone number, 
used by machines (usually computers) to refer to each other when sending information 
through the Internet. This allows machines passing the information onwards on behalf of the 
sender to know where to send it next, and for the machine receiving the information to know 
that it is the intended destination. 
List of Internet Terminology 
ARPANET: The acronym stands for Advanced Research Projects Agency Network. ARPA of the 
United States Department of Defense developed ARPANET, which became the world's first packet 
switching network. Internet is the successor of ARPANET.
COMPUTER OPERATIONS  PACKAGES 
Internet Service Provider: A company, which provides users with an access to the Internet, is known 
as an Internet service provider or Internet access provider. ISP, as it is called, offers email accounts 
and other services like remote storage of files for its customers. 
OSI Model: The Open System Interconnection Model is used to describe a layered communication 
and network protocol design of a network. It is composed of seven layers, each of which performs 
certain functions and provides the layers above it with some services. Go through an elaborate 
description of the OSI model. 
Internet Protocol Suite: It is a set of communication protocols, which are used for the Internet. 
Transmission Control Protocol (TCP) and Internet Protocol (IP) were the two pioneering protocols to 
be introduced in the Internet protocol standard. The Internet protocol suite is composed of a set of 
layers wherein; each layer provides a service to the upper layers in the set. The upper layers deal 
with abstract data while the lower layer protocols translate data into physically transmittable forms. 
PPP: Point-to-Point protocol (PPP) is a data link protocol that facilitates the establishment of a direct 
connection between two nodes on a network. Here is a brief introduction to the Point-to-Point-protocol. 
IP Address: It is a way of numerically identifying an entity on a computer network. The original 
addressing system known as IPv4, used 32 bit addresses. With the growth of the Internet, IPv6 came 
to be used wherein the addresses are composed of 128 bits. You might want to know how to find 
your IP address. 
MAC Address: Media Access Control address (MAC) is the physical hexadecimal address assigned 
to each device on a network. 
Domain Name System: DNS, as it is called, refers to the hierarchical naming system used for 
computers, resources and services on the Internet. It translates the computer hostnames to IP 
addresses. By way of the implementation of DNS, the domain name 'www.buzzle.com' translates to 
its IP address, say, 208.70.178.150. With the help of DNS, domain names can be assigned to Internet 
users. 
Cyberspace: This term coined by William Gibson, is used to refer to the computer networks 
connected to each other and the content they host. It is often used to refer to the Internet. 
WWW: It is a collection of interlinked documents that are accessible over the Internet. It consists of 
millions of web pages that contain text, images, voice and videos. Sir Tim Berners-Lee, a British 
scientist working at CERN, created the World Wide Web. 
W3C: It is the acronym used for the World Wide Web Consortium, which develops standards for the 
web community. 
Website: A website is a set of web pages consisting of text, audio and video. Web servers host 
websites. 
URL: It specifies the location of a resource on the Internet. It consists of the basic address and path. 
Web Page: Web pages are resources of information. They are generally created in the HTML format 
and provide the web users with navigational abilities through hyperlinks to other web pages on the 
web. 
Home Page: The term home page is used to refer to the page that is the default page of any 
website. It is the main page of a complex website. 
Proxy Server: Client machines on a network connect to the proxy server, which forwards the client 
requests to other servers and returns responses to the clients. 
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COMPUTER OPERATIONS  PACKAGES 
Web Server: A web server is a computer program that accepts HTTP requests from web clients and 
provides them with HTTP responses. 
Web Browser: A web browser is a software application that facilitates user interaction with the text, 
audio, video and other information that is located on the web. 
Cache: Web browsers maintain a cache of recently visited web pages. Some of them use an 
external proxy web cache, which is a server program through which web requests pass. This 
enables the browsers to cache frequently visited pages. Even search engines make available 
already indexed web pages through their caches. 
HTTP: Hypertext Transfer Protocol, abbreviated as HTTP, is a communications protocol used for the 
transfer of information over the Internet. A client makes an HTTP request using a web browser to 
which an HTTP response is sent from the server. 
Web Cookie: Also known as an HTTP cookie, it is piece of text that is exchanged between the web 
client and the web server. It is sent by the web server to the web client and returned unchanged 
by the client each time it accesses the server. You might want to know how do websites use 
cookies? 
Session: It is an exchange of information between a computer and its user. It is established for a 
certain period of time after which it ends. 
Hyperlink: A reference in a document to another section of the document or to another 
document is termed as a hyperlink. Hyperlinks are used to redirect the user from one section of a 
page content to another. 
Web 2.0: It is used to describe the changes in the www technology and web design. The term 
deals with the idea of the development of interactivity and connectivity of the web content. 
Internet security: It is one of the major concerns today. As the Internet acts as a communication 
platform that can be accessed by millions of users around the world, it becomes necessary that 
proper measures be implemented. Issues like Internet safety that deal with the content that is 
made accessible over the Internet are equally important. Internet privacy relates to safeguarding 
the privacy of the web users and the sensitive information on the web from hackers and stalkers. 
Internet - A communication Platform 
Internet serves as one of the most efficient means of communication. Computers from different 
parts of the world can be connected to each other to exchange information, thanks to the 
Internet. Emails and chats are excellent means of communication over the Internet. Blogs and 
online forums give the Internet users a platform to reach out to the masses. Here is a list of the basic 
Internet terms associated with the Internet as a communication platform. 
Email: It is a store-and-forward method of writing, sending and receiving written messages. 
Electronic mail is an Internet e-mail system that uses network-based protocols to exchange 
messages between network subsystems. 
Email Address: It identifies the network location to which an email can be delivered. An email 
address is a combination of the user name of the mail user and the host name of the mailing 
system. It is of the form, 'username@domain-name'. An email alias is a forwarding email address. It 
simply forwards emails to specific email addresses. 
Spamming: The act of sending unsolicited bulk messages over an email system is known as 
spamming. It is an undesirable use of the electronic messaging systems. 
Phishing: It is a fraudulent activity of acquiring the sensitive information by the use of a fake identity 
during electronic communication. It is implemented by means of emails and instant messages 
wherein a user is lured to enter his/her details, which are actually captured by a fraudulent 
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COMPUTER OPERATIONS  PACKAGES 
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website. 
Hacking: Hacking is the activity of programmatically gaining access to a computer application 
that is otherwise inaccessible. The act of gaining an unauthorized access to a computer is known 
as hacking. Hacking of passwords that leads to breach of email privacy is a threat to 
communication over the Internet. Internet crime refers to all the criminal activities that are carried 
over the Internet. 
Email Scams: With the increase in the use of email systems, its security needs also rose. Fraudulent 
users started tampering with the email systems to breach security. 
Email Virus: It is a computer code that is transmitted through an email in the form of an 
attachment. The email attachment causes the destruction of some of the files on the receiver 
computer's hard disk and is programmatically emailed to the contacts in the address book of the 
receiver. 
Email Client: It is also known as a mail user agent (MUA). An email client is a front-end computer 
program or an agent that acts as a client for the email server. 
Mail Server: It can also be called Mail Transfer Agent (MTA) and is responsible for receiving 
incoming email from local users and forwarding outgoing mails for delivery. A mail server 
application forms the heart of a messaging system that performs all the functions to keep the mails 
moving over the network. 
SMTP: Short for Simple Mail Transfer Protocol, SMTP is the standard for the transmission of electronic 
mails. The electronic mail server software uses SMTP to send and receive mail messages. ESMTP, 
that is known as extended or enhanced SMTP refers to the protocol extensions made to SMTP and 
is widely used today. 
POP3: Short for Post Office Protocol, POP3 is an application layer Internet standard protocol. It is 
used to retrieve mails from a remote server. Here is a brief introduction to POP3. 
IMAP: Internet Message Access Protocol, as it is called, is another Internet standard protocol used 
for retrieval of emails. 
Internet Chat: It is a real-time Internet chat or synchronous conferencing that is used for group 
communication as well as one-to-one communication over the Internet. Jarkko Oikarinen, a Ph.D. 
from the University of Oulu is the developer of the first Internet chat network. He developed the 
client and server programs for Internet Relay Chat in August 1988. 
Social Networking: Social networking is about building online communities of like-minded people. 
Serving as an excellent platform for sharing of information, social networking is a rage today. 
ADSL: Asymmetric Digital Subscriber Line, abbreviated as ADSL, is used for the transmission of digital 
information using high bandwidths on existing phone lines. ADSL technology is characterized by 
high download and low upload rates. 
Dial-up: It is the means to connect to the Internet using the copper phone lines and a modem. 
Dial-up connections are capable of sending information from the client's end at very slow speeds 
of about 56kbps. 
Modem: It is a device that modulates analog carrier signals to encode digital information and 
demodulates carrier signals to decode information. A cable modem provides access to data 
signals sent over the cable television infrastructure. Modems are commonly used for facilitating 
Internet access. 
Communication Bandwidth: It refers to the data that can be transferred between two points in a 
given period of time. It is expressed in terms of bits per second. It is commonly known as the bit
COMPUTER OPERATIONS  PACKAGES 
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rate. 
Blogs: Blogs are the expressions of the common masses about social or political issues or simply 
anything. Blogs can often be in the form of creative write-ups by writers in different parts of the 
world. 
Internet Forums: It is a bulletin board that serves as a platform for group discussion. Registered users 
are free to contribute to the issues raised in forums thus making them open discussion platforms. 
Usenet: Usenet can be considered as a worldwide bulletin board. Usenet newsgroups serve as a 
repository of messages posted from users around the world. 
Internet - A Search Platform 
Internet that hosts an ocean of information has also become an excellent platform for information 
retrieval. The Internet search engines, which crawl and index web pages, organize the information 
on the Internet and the web directories link to information on the network. Here is a list of the 
Internet terms related to the Internet as a search platform. 
Internet Search Engine: It is an information retrieval system that is designed to help find information 
over the Internet. Search engines use algorithms to scan the huge information base of the Internet 
and sort it making it retrievable for the web users. 
Web Crawler: Popularly known as a spider, a web crawler is a program that browses the World 
Wide Web in an automated manner. Search engines use the crawling technologies to index pages 
on the web. 
Search Engine Optimization: The process of organizing the content of a website with intent to 
increase its relevance with respect to keywords and search engines. The process of optimization 
involves editing website content and HTML coding to support search engine strategies of ranking 
and indexing. 
Internet Bookmark: The Internet browsers of the modern times aim at enabling the users to organize 
the web pages they access. Links once visited can be saved in the favorites or preferences 
categories. Bookmarks are usually integrated into browsers. Social bookmarking is a method used 
by Internet users to store and manage web pages. 
Web Directories: It is a directory, which links to other websites and organizes those links. They should 
not be mistaken as being search engines. 
OTHER TERMS 
Router: A router connects two or more logical subnets and performs the functions of routing and 
forwarding information. 
Intranet: It is a relatively smaller private network that uses the Internet protocols and connectivity. It 
is an extension of the Internet and is privately used by organizations. 
Extranet: It is a private network that uses Internet technology to share a part of the business 
information and operations with suppliers and customers. It can be a part of a company's intranet 
that provides access to the users outside the company. 
Virtual Private Network: It is a private network that allows the exchange of information between 
computers over a shared or a public network. 
Wireless Networking: It refers to computer networking that is carried out over the wireless media. 
Broadband Internet: Broadband connectivity to the Internet provides the users with a high-speed 
Internet access.
COMPUTER OPERATIONS  PACKAGES 
Dial-up Internet: In this type of access to the Internet, the user's computer is attached to a modem 
connected to a telephone line. Dial-up Internet access involves a modem that dials into an 
Internet service provider to establish a connection. 
Satellite Internet: Internet services that make use of the satellite communication media are termed 
as satellite Internet services. They are used in locations that are mobile thus making terrestrial 
Internet connectivity, an impossibility. 
Some Funny and Interesting Internet Terms 
Googling: The Google search engine, being the most popularly used one, has made the word, 
'google' synonymous to the concept of search engines. Searching the Internet by using the 
Google search engine is known as googling. 
Copypasta: If text is copy pasted from somewhere and posted in a forum, it is termed as a 
copypasta. The source is often unknown in such cases. 
Egosurfer: The web users who search over the Internet for themselves fall under the class of 
egosurfers. I am sure most of you play an egosurfer once in a while. 
Netiquette: This term is short for net etiquette and refers to the principles of courtesy and 
consideration for the people using the Internet. It refers to certain basic principles to adhere to 
while using the Internet. The general ethical principles to be followed in relation to using mailing 
systems of the Internet are termed as email etiquette. 
Trasher: The users who search over the Internet using all possible means, sometimes even risking the 
Internet security are known as trashers. 
Troll: Trolls are the users who try to become infamous on chat by introducing disturbing links, 
mimicking other users' posts and profiles and fighting with others. 
Youtuber: A person who is addicted to watching videos on the Internet is referred to as a youtuber 
What are the advantages  disadvantages of the Internet? Discuss 
These are far too broad and extending to all realms in life. For instance:- 
1) Access to a wide range of information from any location worldwide where there is 
internet access. i.e. airlines, resorts, books, authors. 
2) Research on any topic i.e. a professor, current affairs. 
3) Online Shopping i.e. for cars, specific dress. 
4) Online ordering and carrying out other business transactions e.g.. Ordering a cheque 
book, advertising a product. 
5) Online conferencing – communicating across international boundaries. 
6) Ability to access e-mail from any location worldwide. 
7) Reading newspapers online. 
Advantages 
Faster Communication 
The foremost target of Internet has always been speedy communication and it has excelled way 
beyond the expectations. Newer innovations are only going to make it faster and more reliable. 
Now, you can communicate in a fraction of second with a person who is sitting in the other part of 
the world. For more personal and interactive communication, you can avail the facilities of chat 
services, video conferencing and so on. Besides, there are plenty of messenger services in offering. 
With the help of such services, it has become very easy to establish a kind of global friendship 
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COMPUTER OPERATIONS  PACKAGES 
where you can share your thoughts and explore other cultures. 
Information Resources 
Information is probably the biggest advantage that Internet offers. Internet is a virtual treasure 
trove of information. Any kind of information on any topic under the sun is available on the Internet. 
The search engines like Google, Yahoo are at your service on the Internet. There is a huge amount 
of information available on the Internet for just about every subject known to man, ranging from 
government law and services, trade fairs and conferences, market information, new ideas and 
technical support, the list is simply endless. 
Students and children are among the top users who surf the Internet for research. Today, it is almost 
required that students should use it for research or the purpose of gathering resources. Even 
teachers have started giving assignments that require extensive research on the Internet. Besides, 
you can have an access to latest researches in the field of medicine, technology and so on. 
Numerous web sites such as America's Doctor also allow you to talk to the doctors online. 
Entertainment 
Entertainment is another popular raison d'être why many people prefer to surf the Internet. In fact, 
the Internet has become quite successful in trapping the multifaceted entertainment industry. 
Downloading games or just surfing the celebrity websites are some of the uses people have 
discovered. Even celebrities are using the Internet effectively for promotional campaigns. Besides, 
there are numerous games that can be downloaded for free. The industry of online gaming has 
tasted dramatic and phenomenal attention by game lovers. 
Social Networking 
One cannot imagine an online life without Facebook or Twitter. Social networking has become so 
popular amongst youth that it might one day replace physical networking. It has evolved as a 
great medium to connect with millions of people with similar interests. Apart from finding long-lost 
friends, you can also look for job, business opportunities on forums, communities etc. Besides, there 
are chat rooms where users can meet new and interesting people. Some of them may even end 
up finding their life partners. 
Online Services 
The Internet has made life very convenient. With numerous online services you can now perform all 
your transactions online. You can book tickets for a movie, transfer funds, pay utility bills, taxes etc., 
right from your home. Some travel websites even plan an Itinerary as per your preferences and 
take care of airline tickets, hotel reservations etc. 
e-commerce 
The concept of e-commerce is used for any type of commercial maneuvering or business deals 
that involves the transfer of information across the globe via the Internet. It has become a 
phenomenon associated with any kind of shopping, business deal etc. You name a service, and e-commerce 
with its giant tentacles engulfing every single product and service will make it available 
at your doorstep. Websites such as eBay allow you to even bid for homes, buy, sell or auction stuff 
online. 
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Additional advantages 
1. Global Audience 
Content published on the World Wide Web is immediately available to a global 
audience of users. This makes the World Wide Web a very cost-effective medium to 
publish information. Reaching more than 190 countries. 
2. Operates 24 hours, 7 days a week 
You don't need to wait until resources are available to conduct business. From a 
consumer's perspective as well as a provider's business can be consummated at any 
time. The fact that the Internet is operational at all times makes it the most efficient 
business machine to date.
COMPUTER OPERATIONS  PACKAGES 
3. Relatively Inexpensive 
It is relatively inexpensive to publish information on the Internet. At a fraction of the 
cost to publish information by traditional methods, various organizations and 
individuals can now distribute information to millions of users. It costs only a few 
thousand dollars to establish an Internet presence and publish content on the Internet. 
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4. Product Advertising 
You can use the World Wide Web to advertise various products. Before purchasing a 
product, customers will be able to look up various product specification sheets and 
find out additional information. You can use the multimedia capabilities of the World 
Wide Web to make available not only various product specification sheets but also 
audio files, images, and even video clips of products in action. The beauty of the Web 
is that it allows customers to explore products in as much detail as they desire. If the 
client just wants a general overview, he or she can look at the advertising information. 
For those wanting more in depth information, you can provide white papers and 
product descriptions for download. The Web allows a business to provide timely 
information, you can simply place the information on the Web page and it is available 
immediately for your customers. 
5. Distribute Product Catalogs 
The World Wide Web is a very effective medium for distributing product catalogs. In 
the old days, putting together a product catalog used to be very costly in terms of 
time and money needed to publish and distribute it. The World Wide Web changes all 
this by allowing content developers to put together a sales catalog and make it 
available to millions of users immediately. Furthermore, unlike printed product 
catalogs that are usually updated around once a month, product catalogs on the 
World Wide Web can be updated as needed to respond to various changing market 
conditions. 
6. Online Surveys 
Traditional methods of performing surveys are often relatively slow and expensive 
compared to online surveys conducted on the Internet. For example, in order to fill out 
various needs of customers or what they would like to see in a future product, it's often 
necessary to compile a list of address and mail a questionnaire to many customers. 
The success of such an attempt is not always guaranteed and can be very costly in 
terms of mailing the questionnaires and entering responses to a databases and 
analyzing it. On the other hand, you can use the World Wide Web to automate the 
whole process. For example, you can set up a CGI script to conduct online surveys. 
Results of such a survey can be automatically updated to a database. This database 
can then be used to keep a pulse on various opinions and needs of customers. 
7. Announcements 
With the World Wide Web, you can distribute various announcements to millions of 
users in a timely manner. Because there is virtually no time lag from the time it takes to 
publish information to making the information available to users, the Web is an ideal 
medium to publicize announcements. As more people discover the virtues of the Web 
and get connected to the Internet, the Web will become the medium of choice for 
many organizations and individuals to publicize various announcements. 
8. Provide Technical Support 
You can also use Web site to provide technical support to users. Because Web pages 
can be updated immediately with new information, various technical support 
literature can be immediately modified in light of new findings and developments. This 
can be accomplished without having to distribute changes to all users affected by 
any changes using traditional mediums of information distribution, which are often 
quite costly compared to the World Wide Web. 
9. Create Online Discussion Forums 
By using applications such as WebBoard, it's possible to set up online discussion forums 
on the Web. 
10. Obtain Customer Feedback 
The interactive nature of the World Wide Web is ideal for obtaining customer 
feedback. You can easily set up a CGI script to obtain customer feedback about a 
product or service. Because customer feedback submitted by customers can be read
COMPUTER OPERATIONS  PACKAGES 
immediately, it's possible to respond to various customer concerns in a timely manner, 
increasing customer satisfaction and quality of customer service. 
11. Immediate Distribution of Information 
When information is added to a Web site, it's immediately available for browsing by 
millions of Internet users. The World Wide Web is an ideal medium of information 
distribution because it takes away the time lag associated with publishing content and 
actually making it available to users 
12. Easy Integration with Internal Information Systems 
Internet information systems deployed on the Internet can be easily integrated with 
internal information systems managed with office productivity applications such as 
Microsoft Office. 
13. Powerful Content Publishing Tools 
A new breed of Internet aware applications will start emerging in software stores by 
the time you read this. These applications will enable users to develop content for the 
World Wide Web by simply saving as an HTML file. In addition to software developers 
making existing applications Internet aware, various new, powerful, and easy-to use 
Internet content publishing applications are also being developed. These applications 
will make the task of publishing content on the Internet even easier. Most of these 
applications are developed for Windows users. 
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14. Multimedia 
The capability to incorporate multimedia into Web pages is a major advantage of 
using World Wide Web to publish information. For example, many Web sites use sounds 
and video clips to make the content easier and more interesting to browse. 
15. Formatting Capabilities 
Content published on the World Wide Web can be richly formatted by using various 
HTML tags and graphic formats. The capability to do this is a major reason for the 
success of the World Wide Web. In addition to using HTML tags and various multimedia 
formats in Web pages, various interactive controls can also be added to a web page. 
This capability allows Web site content developers to create active Web sites. For 
example, before a user sends some information to a Web server for processing, a 
VBScript or JavaScript subroutine can be used to verify information typed in by the 
user. Various formatting capabilities, along with technologies such as Java and 
VBScript, make the World Wide Web a richly interactive medium that you can use to 
distribute information to millions of users. 
Disadvantages 
Theft of Personal Information 
If you use the Internet for online banking, social networking or other services, you may risk a theft to 
your personal information such as name, address, credit card number etc. Unscrupulous people 
can access this information through unsecured connections or by planting software and then use 
your personal details for their benefit. Needless to say, this may land you in serious trouble. 
Spamming 
Spamming refers to sending unwanted e-mails in bulk, which provide no purpose and needlessly 
obstruct the entire system. Such illegal activities can be very frustrating for you as it makes your 
Internet slower and less reliable. 
Virus Threat 
Internet users are often plagued by virus attacks on their systems. Virus programs are inconspicuous 
and may get activated if you click a seemingly harmless link. Computers connected to the Internet 
are very prone to targeted virus attacks and may end up crashing. 
Pornography
COMPUTER OPERATIONS  PACKAGES 
Pornography is perhaps the biggest disadvantage of the Internet. Internet allows you to access 
and download millions of pornographic photos, videos and other X-rated stuff. Such unrestricted 
access to porn can be detrimental for children and teenagers. It can even play a havoc in marital 
and social lives of adults. 
Social Disconnect 
Thanks to the Internet, people now only meet on social networks. More and more people are 
getting engulfed in virtual world and drifting apart from their friends and family. Even children 
prefer to play online games rather than going out and mingling with other kids. This may hamper a 
healthy social development in children 
The Web uses three standards namely: 
1 URLs (Uniform Resource Locators) – which are web page addresses 
2 HTTP (Hypertext Transfer Protocol) – the language used to design web pages 
3 HTML (Hypertext Markup Language) 
To send e-mail access the Internet, both the sender and receiver need: 
WHAT IS NEEDED FOR INTERNET AND E-MAIL SERVICES 
1) A computer connected to a network, 
2) The windows operating system installed 
3) The communication and or browser software such as Ms-Exchange or Ms-Outlook, 
Internet explorer, Netscape navigator 
4) A modem 
5) Telephone line 
6) Subscription to an ISP (Internet Service Provider). 
What do you need to get connected? 
To connect to the internet you need: 
1) A computer 
2) A telephone line 
3) A modem - the type of modem you need to use is dependant on the type of 
connection you have. Some of the choices are: 
An analogue modem and an ordinary phone line. This type of modem links your 
computer to the phone and converts computer signals to analogue phone line 
signals - and back again. Typical analogue modem speeds are 56Kbps (bps 
stands for bits per second) which means they can receive about 6000 characters 
per second. This is the slowest and oldest type of connection and becoming less 
common with the introduction of broadband. 
An ISDN line and terminal adaptor. This digital connection is slightly faster than an 
analogue connection. 
An ADSL or cable telephone line and broadband modem. Broadband modems 
are much faster than the other two options and their use is increasing. 
4) An account with an ISP (Internet Service Provider) 
5) Browser software 
ISPs are the companies who provide you with access to the internet. Commonly used ISPs include 
Freeserve, AOL, Virgin, Tesco, BT and many more. Most offer the same basic package of Internet 
access, email addresses, web space for your own pages and local rate call charges. 
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COMPUTER OPERATIONS  PACKAGES 
A browser is a program that allows you to view the pages on the Web. The most widely used are 
Internet Explorer and Firefox. 
All browsers will have a number of similar features to help you use the Web: 
• Forward and back buttons to move between pages 
• A history folder which stores details of recently visited web pages 
• A stop button if a page is taking too long to load 
• Favorites and bookmark options to store often visited pages 
• Options to cut, copy, save and print the information viewed 
Electronic mail 
Electronic mail or email is a means of sending messages, text, and computer files between 
computers via the telephone network. Because the telephone network covers the whole world, 
email enables you to communicate world wide. 
Email and web mail 
Email 
To set up email you need: 
• A computer 
• An internet connection via an analogue modem (ordinary phone line) or terminal adaptor 
(ISDN) or broadband modem (ADSL and cable) 
• An account with an ISP (Internet Service Provider) 
• Email software 
Your Internet Service Provider will give you an email account, a password and a mailbox such as 
yourname@hostname.co.uk. You can also set up an email account with a mailbox and passwords 
with non-ISPs such as Google and Hotmail. 
With a dial-up connection, you have to pay the cost of your internet phone calls (local rate), and 
in most cases a subscription to your provider (though some are free). A broadband connection is 
'always on', with only a flat-rate subscription. Very few people pay by the minute nowadays and 
the majority of people pay a monthly fee for broadband access. 
Anti-virus scanning is becoming standard on email accounts and many email providers now offer 
an anti spam (electronic junk mail) service. 
Web mail 
Web mail, as its name suggests, is web-based email. To use web mail, you do not need any email 
software - just a computer connected to the internet via any one of the connection types listed 
above, and a browser. 
Users simply sign up to the web mail service of a web portal such as MSN or Yahoo. They are given 
a unique user name and a personal mailbox on the portal's email server, and they can then send 
and receive messages via a special web page. 
A basic web mail account is usually free, although this will have a very limited amount of storage. 
The advantage of web mail is that users can receive and send mail from any computer in the 
world with internet access. If you have a dial-up connection you can download your emails and 
then read them offline to avoid staying on-line for long periods. 
Some ISPs will enable their regular email customers to access their mailbox via web mail as well as 
through the email software on their PC. 
Features of email 
• Automatic reply to messages 
• Auto forward and redirection of messages 
• Facility to send copies of a message to many people 
• Automatic filing and retrieval of messages 
• Addresses can be stored in an address book and retrieved instantly 
• Notification if message cannot be delivered 
• Automatically date and time stamped 
• Signatures can be attached 
• Files, graphics or sound can be sent as attachments, often in compressed formats 
• Web mail and mobile email can be used to receive and send messages while on the 
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move.
COMPUTER OPERATIONS  PACKAGES 
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Using email 
• Broadband email 
- Your connection is always on - so simply write and address your message and hit 'send' to 
send your mail and 'receive' to download any incoming messages from your email 
provider's server. 
• Web mail 
- Connect to the internet (if using a dial-up account) and open your browser. 
- navigate to your web mail provider's portal and enter your user-name and password. 
- all incoming mail will now be visible, and you can also compose and send mail, and 
download attachments to your computer. 
- When you're done, log out and close your connection. 
• Dial-up email 
- Prepare your message offline as typing your message online will increase phone charges. 
- Connect to the internet and log on to your email account. 
- Send your message and download any incoming mail sitting on your service provider's 
computer. 
- Log off and close your connection. 
Email is evolving... 
• Many mobile phones already allow messages to be sent to the recipient's email inbox 
while the sender is on the move. The latest generation of mobile phones enables users to 
send and receive wireless email in exactly the same way as a static computer. 
• Email can be sent and received via digital TV, specially adapted phones, public kiosk 
terminals and the latest generation of games console. 
• A spreading network of wireless 'hotspots' in public places allows people to send and 
receive email via laptop computers. 
• A new range of in-car phones will enable motorists to check their email on the road 
Benefits and concerns of using email 
Email benefits 
• Fast delivery of your message 
• Available 365 days, 24 hours per day - and, with web mail, wherever you are in the world 
as long as you have access to the internet. 
• Cheap: when using broadband, individual mail transfers are effectively free. When going 
online from a dial-up account, calls are charged at local rates and (for conventional 
email) need only last a few seconds. 
• Facility to send the same message to more than one person 
Email concerns 
• It can only be sent to people who themselves have access to the internet. 
• Viruses are easily spread via email attachments - anti virus measures must be in place to 
avoid this and are now offered by many e-mail providers. 
• Phishing - sending an e-mail to a user falsely claiming to be a legitimate company to scam 
the user into providing information such as personal information and bank account 
numbers on a bogus website. The details will then be used for identity theft. 
• No guarantee the mail will be read until the user logs on and checks their mail. 
• Spam! Or Junk mail 
HEALTH AND SAFETY 
HEALTH PROBLEMS ASSOCIATED WITH COMPUTER USE AND POSSIBLE SOLUTIONS 
Are Computers a Health Hazard? 
The first thing to know is that the risks are not likely to affect you unless you are a habitual 
computer user. In other words, you're sitting at the computer pretty much all day, every day. Oh 
yeah... that's all of us! That's not to say that the occasional computer user won't have problems. 
Everyone's level of sensitivity is unique.
COMPUTER OPERATIONS  PACKAGES 
The buzz started in the 80's and culminated in the 1992 Health and Safety DSE (Display Screen 
Equipment) regulations. Then came Carpal-Tunnel Syndrome followed by ergonomics. The hype 
has subsided, since we all know the computer isn't going to kill us - but we have learned a lot over 
the past 20 years about potential health risks and more importantly, we've learned ways to avoid 
being at risk when we're using computers. 
Let's look at some of the most common medical problems and what you can do to avoid them. 
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1. Eye Strain: 
• Position your terminal at right angles to the window if possible; avoid facing directly into 
bright light (coming at you from behind your computer screen). 
• Install an anti-glare screen. 
• Adjust the brightness controls on the screen until they are comfortable to your eyes. 
2. Carpal Tunnel Syndrome: 
• Adjust your chair or table height to have your elbow angle at 90-100 degrees. 
• Position your keyboard so that you don't have to bend your hands uncomfortably upward 
to reach the keys; place a raised wrist rest on the table in front of the keyboard if 
necessary. 
• Clinch your fists, hold for one second, then stretch your fingers out wide and hold for 5 
seconds. 
• Organize your workday, if possible, to intersperse other tasks with your computer work so 
that you're not sitting at the computer for several hours without a break. Variety is key. 
• Hold the mouse loosely and click lightly. 
3. Neck and Back Strain: 
• Check your posture - sit up straight. Thanks Mom. 
• The monitor screen surface should be approximately 18-24 inches away from your torso. 
• Preferably chairs should be on wheels, have backrest tilt adjustment, and have arms. 
• Be sure you have enough desktop space for work papers and other equipment. 
4. Conjunctivitis (itchy, bloodshot eyes) and Dermatitis: 
• Be sure the screen doesn't flicker or wave - this could indicate that service or adjustment is 
needed. 
• Look away from the screen periodically. 
• Don't forget to blink - your eyes need the moisture. 
5. The vision disorder 
Due to excessive computer use has been identified as Computer Vision Syndrome. Symptoms are 
dry eyes, headaches, blurred vision, eyestrain, and shoulder back pain. 
• To alleviate the problem it is suggested that computer users take regular 
breaks, blink their eyes frequently, occasionally close their eyes for a few 
minutes and every fifteen minutes or so look away from the computer to 
stare at an object in the distance. 
6. For the back pain and other muscular related problems, 
It is suggested that people get up every hour, stretch and move around for about five minutes. 
They should also do an activity which moves each foot and leg. 
• A computer user should be seated at least two feet away from the 
screen with the screen below eye level. Their chair should be 
comfortable and they should sit up straight in the chair with feet firmly 
on the floor. They should not cross their legs. 
7. Posture-related injuries 
Back and neck pain, headaches, and shoulder and arm pain are common computer-related 
injuries. Such muscle and joint problems can be caused or made worse by poor workstation 
design, bad posture and sitting for extended periods of time. 
Although sitting requires less muscular effort, it still causes fatigue and requires parts of the body to 
be held steady for long periods of time. This reduces circulation to the muscles, bones, tendons 
and ligaments and can result in stiffness and pain. If a workstation is not set up properly, these 
steady positions can put even greater stress on muscles and joints.
COMPUTER OPERATIONS  PACKAGES 
Prevention tips – muscle and joint injuries 
Suggestions to reduce the risk of muscle and joint problems include: 
• Use an adjustable desk designed for use with computers; position the monitor so that it is 
either at eye level or slightly lower. 
• Position your keyboard at a height that allows your elbows to rest comfortably at your side. 
Forearms should be roughly parallel with the floor and level with your keyboard. 
• Adjust your chair so that your feet rest flat on the floor. 
• Use a footstool (if your feet do not rest on the floor when the chair is adjusted for good arm 
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position). 
• Switch to an ergonomic chair, which helps your spine to naturally hold its curve while 
sitting. 
• Use an ergonomic keyboard to offer your hands and wrists a more natural holding position. 
• Take frequent short breaks and go for a walk or perform stretching exercises at your desk. 
Stand often. 
8. Overuse injuries of the upper limbs 
Muscles and tendons can become painful with repetitive movements and awkward postures. This 
is known as ‘overuse injury’ and these typically occur in the elbow, wrist or hand of computer users. 
Symptoms of overuse injuries in the upper limbs include pain, swelling, stiffness of the joints, 
weakness and numbness. 
Prevention tips – overuse injuries 
Suggestions to reduce the risk of overuse injuries include: 
• Keep your mouse at the same height as your correctly positioned keyboard. 
• Position the mouse as close as possible to the side of the keyboard. 
• Use your whole arm, not just your wrist, when using the mouse. 
• Type lightly and gently. 
• Mix your tasks to avoid long, uninterrupted stretches of typing. 
• Remove the hands from the keyboard when not actively typing, to allow the arms to relax. 
9. Eyestrain 
Focusing your eyes at the same distance point for extended periods of time causes fatigue. The 
human eye structurally prefers to look at objects further than six metres away, so any work 
performed close-up puts extra demands on the eye muscles. 
The illuminated computer screen can also contribute to eye fatigue. While there is no evidence 
that eye fatigue is associated with damage to the eyesight, computer users may experience 
symptoms such as blurred vision, temporary inability to focus on faraway objects and headaches. 
Prevention tips – eyestrain 
Suggestions to reduce the risk of eyestrain include: 
• Make sure your primary light source (such as a window) is not shining into your face or 
directly onto the monitor. 
• Tilt the monitor slightly to eliminate reflections or glare. 
• Make sure your computer screen is not too close to your face. 
• Position the screen so that it is either at eye level or slightly lower. 
• Reduce the contrast and brightness of your screen by adjusting the controls on the 
monitor. 
• Frequently look away from the screen and focus on faraway objects. 
• Have regular eye examinations to check that blurring, headaches and other associated 
problems are not caused by any underlying disorders. 
Pain in the buttocks 
Pain in the buttocks radiating down the thigh can be caused by a chair seat that is too long and 
causing pressure behind the knees or from inadequate lumbar support. 
Pain in the shoulders 
 Pain in the shoulders can be caused by having arms on the chair that cannot be adjusted 
this causes the user to sit with the arms sticking out.
COMPUTER OPERATIONS  PACKAGES 
 Sitting at the desk with one elbow supported on the desk and the other held lower or 
twisting the torso to look at the monitor will also cause pain. 
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Pain in the knees 
 Pain in the knees can be caused by the fact that when the chair has been adjusted to the 
correct height to allow the fingers to be horizontal to the keys, the feet are left 
unsupported, the solution is to purchase a footrest the small step type called (twin plus in 
the Lyreco catalogue are best because they do not take up much space under the desk, 
they can be adjusted according to the height of the person using them.) 
If transcription is carried out it is better to have a large surface area on the footrest and the 
ability to keep this level to support the footswitch. 
 Pain in the knees can also be caused by a seat that is too long resulting in pressure behind 
the knees. 
Eye strain 
 Eyestrain can be caused by glare from the monitor or from overhead lights. Ideally the 
desk should be placed between lights and not directly under them. If this is not possible 
you may be able to switch the overhead light off and use an angle poise lamp. 
 Glare from windows without blinds or with incorrectly fitted blinds. 
 Where there are casement window at the top and blinds cannot be used there is often 
glare from the sun on the screen. Some vertical blinds are not efficient and additional 
blackout roller blinds would improve efficiency and keep the room cool. If blinds cannot 
be fitted it may be possible to fit a tinted transparent film to the window. 
Other solutions: 
 See the Optician about middle distance correction 
 Ask about a slight tinted coating to your glasses 
 Contact IT if there is any flicker on your screen 
 If your monitor is old and small (14inch CGA, VGA) it will have poor resolution and should 
be replaced with a 17inch SVGA or XGA. 
 Clean your screen 
 Adjust your contrast or brightness 
 Make sure that you are not too far away from the screen (correct viewing distance is 18-20 
inches) 
WORD PROCESSING TERMINOLOGY 
Spelling checker 
• A companion application that you use with a word-processing application to check for 
misspelled words. 
• A word processing function which searches for and corrects misspellings by comparing a 
document's words with those in a built-in spelling dictionary. 
• spell-checker: an electronic dictionary in a word processor that can be used to catch 
misspelled words 
• In computing terms, a spell checker or spelling checker is a design feature or a software 
program designed to verify the spelling of words in a document, helping a user to ensure 
correct spelling. A spell checker may be implemented as a stand-alone application 
capable of operating on an block of text; however, spelling checkers are more often 
implemented as a feature of a larger document-related application, such as a word 
processor or an email client. 
Macros 
• In the context of programming by demonstration, this usually refers to any procedure 
created by recording the user's actions as they are carried out. Unlike the conventional 
computer-science definition, the use here does not necessarily have any implications 
about how the procedure is executed (whether it is expanded in-line using textual 
substitution or called as a function). 
• A macro in computer science is an abstraction, whereby a certain textual pattern is 
replaced according to a defined set of rules. The interpreter or compiler automatically 
replaces the pattern when it is encountered. In compiled languages, macro-expansion 
always happens at compile-time. The tool which performs the expansion is sometimes 
called a macro-expander. ...
COMPUTER OPERATIONS  PACKAGES 
rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 125 
Header 
Text that appears at the top of every page of a document when it is printed. 
Footer 
• Located at the bottom of the page, it usually contains information about the page author 
or the sponsor. You may also find copyright information and the date the page was last 
updated. 
• Text that appears at the bottom of every page in a document. 
Mail merge 
• The process by which information (e.g. names and addresses) from a database or other list 
and inserted into a standard document or letter to produce multiple personalized copies. 
• A mass-mail facility that takes names, addresses, and (sometimes) pertinent facts about 
recipients and merges the information into a form letter or another such basic document. 
• The transfer of data from one computer file to address and/or personalize mailing items in 
another. 
JUSTIFICATION 
HARD RETURN 
SPREADSHEET TERMINOLOGY 
Microsoft Excel is a spreadsheet program written and distributed by Microsoft for computers using 
the Microsoft Windows operating system and for Apple Macintosh computers. It features an 
intuitive interface and capable calculation and graphing tools which, along with aggressive 
marketing, have made Excel one of the most popular microcomputer applications to date. ... 
Workbook 
• A spreadsheet document that contains one or more worksheets, a Microsoft Excel 
document. 
• A collection of related worksheets contained within a single file. (in spreadsheet 
applications). 
• The workbook is the main document used in software programs like Excel. A workbook 
consists of individual worksheets, like an accountant's workbook, each of which can 
contain data. Basically, a workbook is a very sophisticated ledger. 
Worksheet 
• A single spreadsheet that contains rows and columns of data. In Excel, a worksheet will 
have a little white tab at the bottom of the screen. A worksheet is treated like a database 
table. 
• An electronic spreadsheet containing 256 columns by 16,384 rows. (in spreadsheet 
applications). 
• A work area comprised of rows and columns, also known as a spreadsheet. 
x-axis label 
• A label describing the x-axis of a chart. (in spreadsheet applications 
Cell An intersection of a row and column, the smallest element in which you can enter data. 
Column A vertical selection of cells identified by one or more letters, starting with A at the left side 
of the spreadsheet. 
Row A horizontal selection of cells identified by a number, starting with 1 at the top of 
thespreadsheet. 
Formula An equation that performs an operation on cell data and displays the result. For example, 
to add the contents of cells A1 and A2, and display the results in A3, cell A3 would contain 
=A1+A2, a simple formula. 
Function A pre-defined formula that allows you to quickly perform a more difficult operation on cell 
data, such as finding the average of a range of numbers. Functions always take 
arguments, or additional information that enables the computation to occur. For 
example, the argument to the AVG, or average, function is the range of cells to be 
averaged: =AVG(A1..C10) averages all cells between A1 (in the upper left) and C10 (in
COMPUTER OPERATIONS  PACKAGES 
rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 126 
the lower right). 
Cell reference 
• The column number and the row letter of a cell. 
• The address or name of a specific cell. Cell references may be used in formulas and are 
relative or absolute. (Spreadsheet application). 
• A cell name used in a formula. 
Cell pointer 
• A highlighted rectangle around a cell that indicates the active cell. (Spreadsheet 
application) 
Relative cell reference 
• Used to indicate a relative position in a worksheet. This allows you to copy and move 
formulas from one area to another of the same dimensions. Excel, for example, 
automatically changes the column and row numbers to reflect the new position. (in 
spreadsheet applications). 
• Cell references in formulas that change when Excel copies them to another location. 
Absolute cell reference on the Web: 
• A cell reference in which a dollar sign ($) precedes both the column and row portions of 
the cell reference. 
Mixed cell reference 
• Cell reference in which either the column or the row is never adjusted if the formula 
containing it is copied to another location. 
Cell address 
• Usually the intersection of a cell's row and column. 
• Unique location identified by intersecting column and row coordinates. (Spreadsheet 
application) 
What if analysis 
• The process of playing with numbers to see how they interact in a spreadsheet. 
Freeze panes 
• Freezing panes prevents the data in the panes from scrolling as you move to different 
areas in the worksheet. 
Goal seek on the Web: 
• Goal Seek is a tool that is used to find the value needed in one cell to attain a result you 
want in another cell. 
Formula 
• A set of instructions that you enter in a cell to perform numeric calculations 
(adding, multiplying, averaging, etc.); for example, +A1+B1. (in spreadsheet 
applications) 
• Instructs the spreadsheet to perform a calculation using the contents of a specific 
cell or range of cells 
Filter 
• A program that processes individual, personal preferences in an attempt to deliver 
relevant information to a particular end user. 
Solver 
• Solver is a tool used to perform what-if analyses to determine the effect of changing 
values in tow or more cells on another cell. 
Recalculation 
• The act of calculating again (usually to eliminate errors or to include additional data); 
recalculation yielded a much larger value 
Absolute cell reference: 
A cell address in a formula that does not change when copied to 
another cell. An absolute reference has the form $A$1. 
Active cell: 
The selected cell in a worksheet. The active cell is surrounded by a 
heavy border and is identified by the cell address.
COMPUTER OPERATIONS  PACKAGES 
rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 127 
Argument: 
The information that a function uses to produce a new value or 
perform an action. For example, a new value is displayed when the 
SUM function adds the argument (A6:A12). An argument consists of 
numbers, references, text, operators, or error values. 
Ascending: 
A method of ordering a group of items from lowest to highest, such 
as from A to Z. 
AutoFilter: 
Displays all records that meet the criteria as a subset of the 
database. 
AutoFormat: 
A feature used to format a range of cells with a predefined set of 
attributes. 
AVERAGE function: 
Sums the numbers in the specified range and then divides the sum 
by the number of non-zero cells in the range. 
Cell reference: 
An unique address given to a cell; the coordinates of the 
intersection of a column and a row. 
Cell: Basic unit of a worksheet into which you enter data. 
Chart: 
A graphic representation of worksheet data. Values from 
worksheet cells are displayed as bars, lines, or other shapes. 
Common chart types are pie, bar, line, and area. 
Column heading: 
The lettered gray area at the top of each column that identifies the 
letter of the column, such as column B. 
Comment: 
A note that explains, identifies, or comments on the information in a 
specific cell or range of cells. 
Condition: 
Made up of two values and a relational operator, is true or false for 
each cell in the range. 
Conditional formatting: 
Allows you to apply formatting that appears only when the value in 
a cell meets conditions that you specify. 
Criteria: 
The conditions that control which records to display in a query; the 
words or values used to determine the data that appears in a data 
list. 
Currency style format: 
Displays a dollar sign to the left of the number, inserts a comma 
every three positions to the left of the decimal point, and displays 
numbers to the nearest cent (hundredths place). 
Data table: 
Range of cells that shows the answers generated by formulas in 
which different values have been substituted. 
Data validation: 
Restricts the values that may be entered into a cell by the 
worksheet user. 
Debugging: Process of finding and correcting errors in the worksheet.
COMPUTER OPERATIONS  PACKAGES 
rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 128 
Descending: 
A method of ordering a group of items from highest to lowest, such 
as from Z to A. 
Dummy data: Used in place of actual data to verify formulas in the template. 
Embedded chart: 
A chart that exists on a worksheet instead of on a separate chart 
sheet. 
Exploded Pie chart: A Pie chart with one or more slices offset. 
Filter: 
A set of criteria you can apply to records to show specific tasks, 
records, or resources. The tasks, records, or resources that match 
your criteria are listed or highlighted so that you can focus on just 
the information you want. 
Formula: 
A sequence of values, cell references, names, functions, or 
operators that produces a new value from existing values. A 
formula always begins with an equal sign (=). 
Function: 
A built-in formula; a named and stored procedure that performs a 
specific operation and returns a value. 
Goal seeking: 
Used if you know the result you want a formula to produce by 
determining the value of a cell on which the formula depends. 
Gridlines: The horizontal and vertical lines on the worksheet. 
IF function: 
A function that tests the content of the cell, performs a calculation, 
and displays a value or text based on whether the test is true or 
false. 
Label: Row title or column title. 
Legend: A box containing the name of each data series in a chart. 
MAX function: Displays the highest value in a range. 
MIN function: Displays the lowest value in a range. 
NOW function: Used to enter the system date in a cell in the worksheet. 
PivotChart: 
An interactive chart that provides the user with ways to graphically 
analyze data by varying the fields and categories to present 
different views. 
PivotTable: 
An interactive worksheet table that summarizes data using a 
selected format and calculations. It is called a pivot table because 
you can rearrange the table structure around the data.
COMPUTER OPERATIONS  PACKAGES 
Protected cells: Cells that you cannot change. 
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Range: 
Series of two or more adjacent cells in a column or row or a 
rectangular group of cells. 
Reference: A cell address used in a formula. 
Relative cell reference: 
In formulas, a reference to the address of another cell in relation to 
a cell that contains a formula. 
Template: 
Special workbook or worksheet you can create and then use as a 
pattern to create new, similar workbooks or worksheets. 
Unprotected cells: Cells whose values you can change at any time. 
Worksheet: 
A set of rows, columns, and cells in which you store and manipulate 
data. Several worksheets can appear in one workbook, and you 
can switch among them easily by clicking their tabs with the 
mouse. 
X-axis: 
A line, usually horizontal, along the bottom of a chart. The x-axis 
shows the labels for the data series. Also called the horizontal axis. 
Y-axis: 
A line, usually vertical, along the left side of a chart. The y-axis 
shows the values for the data series. 
Part A 
i. Worksheet an electronic spreadsheet containing 256 columns by 16 384 rows. A single 
spreadsheet that contains rows and columns of data . A set of rows, columns and cells in 
which you store and manipulate data 
ii. Cell address usually the intersection of a row and a column. Is the location of a cell on a 
worksheet and is defined by the column letter and the row number. E.g. cell A1 is where 
column A and Row 1 intersect. 
iii. Formula a set of instruction that you enter in a cell to perform numeric calculations = 
A1+B1 
iv. Cell Pointer (cursor) A highlighted rectangle around a cell that indicates the active cell. 
v. Cell an intersection of a row and column, the smallest element in which you can enter 
data. 
Part B 
i. Footer text that appears at the bottom of every page in a document 
ii. Text that appears at the top of every page of a document when it is printed. 
iii. Spell Checker F1 word processing function which searches for and correct misspellings 
by comparing a document’s words with those in built-in spelling dictionary. 
iv. Font is a style and size of type e.g Times New Roman, 12 point is a set of all the 
characters available in one typeface and size, including uppercase and lowercase 
letters, punctuation, and numerals. 
v. Alignment the position of lines in a paragraph in relation to the document’s left and right 
margins i.e. whether they are left-aligned, centered, right-aligned or justified.
COMPUTER OPERATIONS  PACKAGES 
a) State the functions of the Control Unit  Arithmetic Logic Unit. [5]. 
Control unit functions 
Manages input-output to  from the main 
memory 
Interprets instructions in sequence 
Issue commands to all elements of the 
computer 
Directs sequence of 
Directs traffic in the computer [make 
decisions] 
Interprets coded instructions 
Initiates proper commands to other parts 
of the computer. 
Performs the functions of fetch, decode, 
execute, and store. 
Three types of Data Transmission: 
1. SIMPLEX 
Data in a Simplex transmission is always one way. Simplex transmission are not often used because it is 
not possible to send back error or control 
It's like a one-way street. An example of simplex is 
2. HALF DUPLEX 
A half-duplex transmission can send and receive in one direction, but not at the same time. It's like a 
one-lane bridge where two-way traffic must give way in order to cross. Only one end transmits at a 
time, the other end receives. In addition, it is possible to perform error detection and request the 
sender to retransmit information that arrived corrupted. In some aspects, you 
surfing as being half-duplex, as a user issues a request for a web document, then that document is 
downloaded and displayed before the user issues another request. 
Another example of half-duplex is talkback radio, and CB Radio (Citiz 
movies where a truck driver (drivers of very big trucks) communicates to each other, and when they 
want the other person to speak they say over. This is because only one person can talk at a time 
rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 
A.L.U functions 
Performs arithmetic operations 
Performs logical operations 
Performs computations on data. 
operations Is where binary data is acted upon? 
Stores intermediate and final results of 
arithmetic operations 
forms signals to the transmit end. 
television, or Radio. 
can think of Internet 
Citizens Band). You might have seen 
130 
ens
COMPUTER OPERATIONS  PACKAGES 
3. FULL DUPLEX 
Data can travel in both directions simultaneously. There is no need to switch from transmit to receive 
mode like in half duplex. It like a two lane bridge on a two 
two-lane highway. Have you ever watched 
these television talk shows where the host has a number of peopl 
at once. Well, that's full duplex! 
Of course, in the world of data communications, full duplex allows both way communications 
simultaneously. An example can be a consumer, which uses a cable connection not only, rece 
channels, but also the same cable to support their phone and Internet surfing. All these activities can 
occur simultaneously. 
Practical QUESTION 
a. Name any 2 word processing packages 
b. What is page break in word processing and why is it used 
c. How do you save a file on a floppy disk using the word processor you have 
d. How do you underline a block of previously typed text using the word processor you have 
studied? 
e. Explain the difference between 
i. SAVE  SAVE AS 
rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 
people on the show, and they all try to talk 
packages. 
used/ 
studied? 
131 
e receives TV
COMPUTER OPERATIONS  PACKAGES 
ii. COPY  CUT 
iii. DELETE  BACK SPACE 
iv. PORTRAIT  LANDSCAPE 
v. TOGGLE CASE  UPPERCASE 
f. Briefly outline the procedures for performing the following functions in a windows 
environment. 
i. Creating a folder 
ii. Opening a folder 
iii. Searching folders or files 
iv. Renaming a file or folder 
v. Creating a shortcut for a file or 
rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 132 
folder 
vi. Copy file from one folder to another 
vii. Move a file from one folder to 
another 
viii. Deleting a file or folder 
ix. Arrange icons on the desktop 
x. Change screen saver 
xi. Click 
xii. Right click 
xiii. Double click 
xiv. Drag 
xv. Loading windows 
xvi. Shutting down a computer 
xvii. Emptying recycle bin 
xviii. 
g. Briefly outline the procedures for performing the following functions using a spreadsheet of 
your choice 
i. Expanding a cell 
ii. Adding a list of figures in the range A10 to D10 
iii. Insert a full border around a document 
iv. Adding and Renaming Worksheets 
v. Resizing Rows and Columns
COMPUTER OPERATIONS  PACKAGES 
h.Briefly outline the procedures for performing the following functions using a word processor of 
your choice 
rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 133 
1. Opening a Microsoft 
word program for 
typing 
2. Saving a document 
3. Retrieving a document 
4. Setting landscape or 
portrait orientation 
5. Print preview 
6. Formatting text into 
italics 
7. Setting left and right 
margins 
8. Inserting a header or a 
footer 
9. Open a document 
which has been saved 
before 
10. Insert a picture 
11. Insert a table 
12. Printing a word 
document 
13. Exit MS Word 
14. Save a document 
15. Copy a document or a 
word 
16. Double line spacing 
17. Insert a header 
18. Insert page number 
19. Save a document onto 
a floppy disk 
20. Mail merge 
21. JUSTIFYING TEXT 
22. Inserting bullets 
23. Indenting text 
24. Moving a block of text 
25. Copying a block of text 
26. Creating a table 
27. Adding rows to a table 
28. Adding columns to a 
table 
29. Deleting rows of a 
table 
30. Deleting columns of a 
table 
31. Shading a table 
32. Merging cells of a table 
33. Splitting cells 
34. Changing text 
direction 
35. Inserting drop caps 
36. Having 2 columns on a 
word document 
37. Bordering and shading 
a paragraph 
38. Change case of a 
word 
39. Locking a word file with 
a password 
Question 26 
(a) Discuss any 4 possible uses of spreadsheets in a business organization. [8 marks] 
(b) Explain the following terms as used in spreadsheets 
I. Cell 
II. Range. [2 marks each] 
(c) Explain the following terms as used in a word processing 
I. Soft return 
II. Hard return 
III. Thesaurus 
IV. Widow 
V. Orphan. [2 marks each] 
Question 24 
(a) Define an electronic spreadsheet. [3 marks] 
(b) List 5 facilities provided by a spreadsheet. [5 marks] 
(c) What is word processing? [2 marks] 
(d) Explain the following word processing terms 
I. Justification 
II. Hard return 
III. Soft return 
IV. Header 
V. Orientation. [2 marks each] 
Question 15 
Briefly explain the following terms as used in a spreadsheet 
(a) Active cell 
(b) Cell 
(c) Legend 
(d) What if analysis 
(e) Label 
(f) FUNCTION 
(g) GRAPH 
(h) Formula 
(i) Cell address 
(j) Worksheet 
(k) Cell reference 
(l) Relative cell reference 
(m) Cell pointer 
(n) Absolute cell reference 
(o) Mixed cell reference 
(p) Work book 
(q) Goal seek 
(r) Range 
(s) Protected cells 
(t) Freeze panes
COMPUTER OPERATIONS  PACKAGES 
(u) Embedded chart (v) Row  column 
rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 134 
[1 mark each] 
Question 16 
Briefly explain the following terms as used in a Word processing 
(a) Orphan 
(b) Header 
(c) Footer 
(d) TEMPLATE 
(e) Spellchecker 
(f) FONT 
(g) TAB STOPS 
(h) Mail merge 
(i) Font type 
(j) Justification 
(k) Word wrap 
(l) Bold 
(m) Borders 
(n) Bullets 
(o) Hard return 
(p) STATUS BAR 
(q) Indentation 
(r) Soft return 
(s) Widow/Orphan Control 
(t) Widow 
(u) Thesaurus 
(v) Format bar 
(w) Standard bar 
(x) Center alignment 
[1 mark each] 
Question 6 
(a) Define a word processor  give an example [2 marks] 
(b) List down at least 5 facilities provided by a word processor [5 marks] 
(c) Give a suitable term/ phrase that best describes the following statements in word 
processing. 
i) The automatic movement of typed text to the new line, without pressing 
the enter key. 
ii) Different “handwritings” in a computer. 
iii) Line spacing. [1 mark each] 
(d) Define a spreadsheet and give an example [2 marks] 
(e) Give the difference between a spreadsheet  a worksheet [2 marks] 
(f) Give a suitable word/ phrase that best describes the following spreadsheet terms 
I. Cell [2 marks] 
II. Hard copy [2 marks] 
III. Creating a permanent copy of a worksheet on a computer. [2 marks] 
QUESTION 31 
(a) Define the term Operating System. [3 marks] 
(b) State any 4 functions of an operating system. [4 marks] 
(c) State any 3 examples of an Operating system (exclude the Windows family). 
[3 marks] 
(d) Define the following Windows Operating Systems based terms: 
I. Desktop 
II. Icon 
III. Taskbar 
IV. Window 
V. Cascade window [2marks each] 
Question 6 
Expand the following abbreviations. 
a) GIGO 
b) WYSIWYG 
c) LED 
d) LCD 
e) MS DOS 
f) OCR 
g) MICR 
h) CD ROM 
i) ASCII 
j) COM 
k) WIMP 
l) GUI 
m) WIMP 
n) CRT 
o) DBMS 
p) POP 3 
q) HTML 
r) URL 
s) TCP-IP 
t) CAD 
u) RAM 
v) ROM 
w) DSS 
x) LAN 
y) 4GL 
z) UPS 
aa) PABX 
bb) DRAM 
cc) SRAM 
dd) EFT 
ee) WAN 
ff) PC
COMPUTER OPERATIONS  PACKAGES 
rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 135 
gg) MIS 
hh) EBCDIC 
ii) MHz 
jj) OMR 
kk) SDLC 
ll) HTTP 
mm) C 
PU 
nn) DBA 
oo) EPROM 
pp) VDU 
qq) ALU 
rr) DOS 
ss) FORTRAN 
tt) COBOL 
uu) ISP 
vv) CPU 
ww) W 
WW 
xx) DVD 
yy) VOIP 
zz) ISDN 
aaa) U 
RL 
bbb) P 
ROM[20 
marks] 
Question 7 
Explain the following terms in detail, giving examples where applicable. 
a) Computer peripherals 
b) Program 
c) BLUETOOTH 
d) Computer 
e) Hardware 
f) Software 
g) Operating system 
h) Application software 
i) Utility software 
j) Machine language. 
k) Random access memory. [20 marks] 
Question 8 
Explain the following terms as used in word processing or spreadsheet 
a) Menu 
b) Footer 
c) Soft return 
d) Edit 
e) Cell 
f) Label 
g) Chart 
h) Mail merge 
i) Print preview 
j) Work sheet. [2 marks each] 
Questions 
(a) Discuss any 4 possible uses of spreadsheets in a business organization. [8 marks] 
(b) Explain the following terms as used in spreadsheets 
I. Cell 
o The intersection of a row and a column on a spreadsheet in which data can 
be entered. 
II. Range. 
o Series of two or more adjacent cells in a column or row or a rectangular group 
of cells. 
III. [2 marks each] 
(c) Explain the following terms as used in a word processing 
VI. Soft return 
o A soft return is entered automatically by a word processor's word wrap feature 
when the text reaches the end of the line. It is contrasted with a hard return 
which is used primarily to begin a new paragraph. A little known feature of 
Microsoft Word and OpenOffice. ... 
VII. Hard return 
o Made by pressing the return or enter key on the keyboard. A hard return, or 
carriage return, creates a line break and identifies the end of a paragraph. 
VIII. Thesaurus
COMPUTER OPERATIONS  PACKAGES 
136 
o Provides a listing of words and their synonym/related words. 
o Guide to use of terms, showing relationships between them, for the purpose of 
providing standardized, controlled vocabulary for information storage and 
retrieval 
IX. Widow 
o In typesetting, a widow occurs when the majority of a paragraph appears on 
one page with the last line of that paragraph flowing to the top of the 
following page. ... 
o The last line of a paragraph at the top of a page of text. 
X. Orphan. 
o In typesetting, an orphan is the first line of a paragraph appearing on its own 
at the bottom of a page with the remaining portion of the paragraph 
appearing on the following page. The first line of the paragraph was left 
behind by the remaining portion of text. ... 
o Line of type on its own at the bottom of a page. 
[2 marks each] 
Question 24 
(a) Define an electronic spreadsheet. [3 marks] 
(b) List 5 facilities provided by a spreadsheet. [5 marks] 
(c) What is word processing? [2 marks] 
(d) Explain the following word processing terms 
VI. Justification 
a. In typesetting, justification (can also be referred to as 'full justification') is the 
typographic alignment setting of text or images within a column or measure to 
align along both the left and right margin. Text set this way is said to be justified. 
b. The alignment of text in a paragraph so that the margins are all straight on the 
right side, or the left side, or both. E.g. this text is left justified. 
VII. Hard return 
VIII. Soft return 
IX. Header 
o Text that appears at the top of every page of a document when it is printed. 
X. Orientation. 
o Whether page is vertically or horizontally aligned. For example we have portrait and 
landscape orientation. 
o Portrait orientation. The mode in which content is viewed where the width is shorter than 
the height. Portrait orientation mimics the way most reading material is printed, eg, letters, 
newspapers, books. ... 
o Landscape orientation. The mode in which content is viewed where the width is longer 
than the height. Landscape is the traditional orientation for computer viewing and is 
appropriate when viewing spreadsheets, video games, and movies. 
[2 marks each] 
Question 15 
Briefly explain the following terms as used in a spreadsheet 
(a) Active cell 
(b) Cell 
(c) Legend 
(d) What if analysis 
(e) Label 
(f) FUNCTION 
(g) GRAPH 
(h) Formula 
(i) Cell address 
(j) Worksheet 
(k) Cell reference 
(l) Relative cell reference 
(m) Cell pointer 
(n) Absolute cell reference 
(o) Mixed cell reference 
(p) Work book 
(q) Goal seek 
(r) Range 
(s) Protected cells 
(t) Freeze panes 
(u) Embedded chart 
(v) Row  column 
[1 mark each]
COMPUTER OPERATIONS  PACKAGES 
137 
Question 16 
Briefly explain the following terms as used in a Word processing 
(a) Orphan 
(b) Header 
(c) Footer 
(d) TEMPLATE 
(e) Spellchecker 
(f) FONT 
(g) TAB STOPS 
(h) Mail merge 
(i) Font type 
(j) Justification 
(k) Word wrap 
(l) Bold 
(m) Borders 
(n) Bullets 
(o) Hard return 
(p) STATUS BAR 
(q) Indentation 
(r) Soft return 
(s) Widow/Orphan Control 
(t) Widow 
(u) Thesaurus 
(v) Format bar 
(w) Standard bar 
(x) Center alignment 
(y) Hyphenation – is used to eliminate gaps 
in justified text or to maintain even line 
lengths in narrow columns. You can 
hyphenate manually or automatically. 
[1 mark each] 
Question 6 
(g) Define a word processor  give an example [2 marks] 
(h) List down at least 5 facilities provided by a word processor [5 marks] 
(i) Give a suitable term/ phrase that best describes the following statements in word 
processing. 
i) The automatic movement of typed text to the new line, without pressing 
the enter key. 
ii) Different “handwritings” in a computer. 
iii) Line spacing. [1 mark each] 
(j) Define a spreadsheet and give an example [2 marks] 
(k) Give the difference between a spreadsheet  a worksheet [2 marks] 
(l) Give a suitable word/ phrase that best describes the following spreadsheet terms 
IV. Cell [2 marks] 
V. Hard copy [2 marks] 
VI. Creating a permanent copy of a worksheet on a computer. [2 marks] 
QUESTION 31 
(e) Define the term Operating System. [3 marks] 
(f) State any 4 functions of an operating system. [4 marks] 
(g) State any 3 examples of an Operating system (exclude the Windows family). 
[3 marks] 
(h) Define the following Windows Operating Systems based terms: 
I. Desktop 
o The main workspace in a graphical user interface such as Windows or 
Macintosh Systems. Users open and work with files and programs on the 
desktop, and can store files and shortcuts there as well. The user can also 
customize the look of the desktop with images or wallpaper and custom icons. 
o Is the background screen on the computer? It consists of pictures, called icons 
that show cabinets, files, folders, and various types of documents. 
II. Icon 
o A picture or graphical representation of an object on a display screen to 
which a user can point to with a device, such as a mouse, to select a 
particular operation or perform a certain action. 
III. Taskbar 
o The bar usually found at the bottom of a Windows screen. The taskbar shows 
which software programs are open. It also contains the Start button. 
o A windows 95/98 screen elements, displayed on the desktops which includes
COMPUTER OPERATIONS  PACKAGES 
138 
the start button and lists the programs currently running on the computer. 
IV. FOLDER 
o Folder, a virtual container within a digital file system, in which groups of files and 
other folders can be kept and organized. 
V. WIMP 
o WIMP (Windows Interface Manipulation Program, also refers to Windows, Icons, 
Menus and Pointing device - the prehistorical GUI of the 1970's) is a program for 
creating full-screen visual animations synchronized with sound in real time. As 
the only visual input WIMP utilizes graphical user interface (GUI) of Windows 
operation system. Whatever applications windows, icons, images, texts, etc. you 
have open on your desktop - they become an inspiration source for WIMP and 
you. Animations are generated by simple 2- and 3-D effects and filters and their 
superimpositions. As such WIMP can be used as a VJ tool, a screensaver, a cool 
grafix generator or as a piece of conceptual art. 
VI. RECYCLE BIN 
o In the Microsoft Windowsoperating systems, the Recycle Bin is a holding area for 
files and folders that are held before final deletion from a storage device. 
VII. GUI 
o A graphical user interface (GUI) is a type of user interface item that allows people 
to interact with programs in more ways than typing such as computers; hand-held 
devices such as MP3 Players, Portable Media Players or Gaming devices; 
household appliances and office equipment with images rather than text 
commands. A GUI offers graphical icons, and visual indicators, as opposed to text-based 
interfaces, typed command labels or text navigation to fully represent the 
information and actions available to a user. The actions are usually performed 
through direct manipulation of the graphical elements.[1] 
VIII. Window 
o In computing, a window is a visual area, usually rectangular in shape, 
containing some kind of user interface, displaying the output of and allowing 
input for one of a number of simultaneously running computer processes. ... 
IX. Cascade window 
o An arrangement of Windows so each window is neatly stacked with only the 
title bar of each window is showing. 
o Arrange (open windows) on a computer desktop so that they overlap each 
other, with the title bars visible 
[2marks each] 
Question 7 
Explain the following terms in detail, giving examples where applicable. 
a) Computer peripherals 
b) Program 
c) BLUETOOTH 
a. Bluetooth® is the codename for a technology specification for low-cost, short-range 
radio links between mobile PCs, mobile phones and other portable devices, 
and connectivity to the Internet. ... 
b. Bluetooth is the name given to a radio technology making transmission of signals 
over short distances between telephones, computers and other devices, like 
household appliances, without the use of wires. 
d) Computer 
e) Hardware 
f) Software 
g) Operating system 
h) Application software 
i) Utility software 
j) Machine language. 
k) Random access memory. [20 marks] 
Question 8
COMPUTER OPERATIONS  PACKAGES 
139 
Explain the following terms as used in word processing or spreadsheet 
k) Menu 
a. A list of options, each of which performs a desired action such as choosing a 
command or applying a particular format to a part of a document. Menus are 
commonly used in graphical interfaces. 
l) Footer 
m) Soft return 
n) Edit 
o To review a piece of writing, marking and correcting grammatical, spelling, and 
factual errors. The editing process also often includes shortening or lengthening articles 
to fit available space, writing headlines and subheads. 
o) Cell 
p) Label 
q) Chart 
r) Mail merge 
s) Print preview 
t) Work sheet. [2 marks each]
COMPUTER OPERATIONS  PACKAGES 
rmmakaha@gmail.com 140 
ABBREVIATIONS 
1) ALU Arithmetic Logic Unit 
2) ARC net Attached Resource Computer Network 
3) ASCII American Standard Code for Information Interchange 
4) B2B Business-To-Business 
5) BCD Binary Coded Decimal 
6) BIOS Basic Input/Output System 
7) BIS Business Information System 
8) BIT Binary Digit 
9) BLOG Web Log 
10) BSYNC Binary Synchronous Communications (protocol) 
11) C C Programming Language 
12) CAD Computer Aided Design 
13) CAL Computer Aided Learning 
14) CASE Computer Aided Software Engineering 
15) CDMA Code Division Multiple Access 
16) CD-R Compact Disk - Recordable 
17) CD-ROM Compact Disk - Read Only Memory 
18) CD-RW Compact Disk - Rewritable 
19) COBOL Common Business-oriented Language (See HLL) 
20) CODEC Coder/Decoder + Compression/Decompression 
21) COE Common Operating Environment 
22) CPU Central Processing Unit 
23) CRC Cyclic Redundancy Check 
24) CRT Cathode Ray Tube 
25) CSMA/CA Carrier Sense Multiple Access/with Collision Avoidance 
26) CSMA/CD Carrier Sense Multiple Access/with Collision Detection 
27) CSMS Customer Support Management System 
28) DSS Decision Support System 
29) DTE Data Terminal Equipment + Dumb Terminal Emulator 
30) DVD Digital Video Disk 
31) DVD-A Digital Video Disk-Audio 
32) DVD-AR Digital Video Disk-Audio Recording 
33) DVD-R Digital Video Disk-Recordable 
34) DVD-RAM Digital Versatile Disc-RAM 
35) DVD-ROM Digital Versatile Disc-ROM 
36) DVD-SR Digital Video Disk-Stream Recording 
37) DVD-VR Digital Video Disk-Video Recording 
38) DVR Digital Video/Voice Recorder 
39) EBCDIC Extended Binary Coded Decimal Interchange Code [IBM] 
40) EEPROM Electrically Erasable Programmable Read-Only Memory 
41) EFTS Electronic Funds Transfer System 
42) E-MAIL Electronic Mail 
43) EPROM Electrically Programmable Read Only Memory + 
i. Erasable Programmable Read Only Memory 
44) FTP File Transfer Protocol [Internet] 
45) FDDI Fiber Digital Device Interface + 
i. Fiber Distributed Data Interface 
46) FDISK Fixed Disk 
47) FDM Frequency Division Multiplexing 
48) FDMA Frequency Division Multiple Access 
49) FDX Full Duplex 
50) FEC Forward Error Correction 
51) FM Frequency Modulation 
52) FORTRAN Formula Translator (Programming Language)(See HLL) 
53) FTP File Transfer Protocol 
54) GHZ Gigahertz
COMPUTER OPERATIONS  PACKAGES 
55) GIGO Garbage In, Garbage Out 
56) GIS Geographic Information System 
57) GSM Global System for Mobile-Communications (network) 
58) GUI Graphical User Interface 
59) HDD Hard Disk Drive 
60) HDLC High-Level Data Link Control 
61) HLL HIGH LEVEL LANGUAGE 
62) HDTV High Definition Television 
63) HTML HyperText Markup Language 
64) HTTP HyperText Transfer Protocol 
65) Hz Hertz 
66) IP Internet Protocol 
67) IQL Interactive Query Language 
68) ISDN Integrated Services Digital Network 
69) IT Information Technology 
70) LAN Local Area Network 
71) LCD Liquid Crystal Display 
72) LED Light Emitting Diode 
73) LPT Line Printer Terminal 
74) LPT1FirstParallelPrinterPort 
75) LPT2SecondParallelPrinterPort 
76) LPT3 ThirdParallelPrinterPort 
77) MBps Megabytes Per Second 
78) Mbps Megabits Per Second 
79) MBR Master Boot Record 
80) MHz Megahertz 
81) MICR Magnetic Ink Character Recognition 
82) MIDI Musical Instrument Digital Interface 
83) MIS Management Information System 
84) MODEM Modulator/Demodulator 
85) MP3 MPEG Audio Layer 3 
86) MSAV Microsoft Anti Virus [Microsoft] 
87) MS-DOS Microsoft - Disk Operating System [Microsoft] 
88) PDF Package Definition File + Portable Document Format + 
i. Portable Document File + Processor Defined Function + 
ii. Program Development Facility 
89) .PDF Printer Description (file name extension)[Borland, Lotus] 
90) P2P Peer To Peer + People To People 
91) USB Universal Serial Bus 
92) WYSBYGI What You See Before You Get It 
93) WYSIWYG What You See Is What You Get 
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COMPUTER OPERATIONS  PACKAGES 
Basic Computer Terminology 
Computer has turned from being just a technological gadget to personal PC to a super 
technological personal gadget. There is nothing in the world that does not depend on computers. 
You need to understand the basic computer terms and meanings in order to stay up-to-date with 
the world. If you do not know the basic computer terms and definition, you look like a lost soul in 
the most happening world of technology. You need to book a movie ticket, so you need Internet 
access. You have to submit a presentation for your company's project, you need a computer to 
bail you out. Its out of date to use a video cassette for your recordings. Cassettes are like an 
ancient relic, its CD's and DVDs that are in vogue today. And to top it all, USB flash drives have 
created a niche in the minds of tech-savvy people. So before you float your mind in the floating 
point numbers or scratch your head when learning the queries in databases, let us begin with some 
simple basic computer terms for beginners. 
Basic Computer Terms and Definitions 
Computer 
A computer is a computing device that is similar to an automated abacus that can execute a 
program, that is, a sequence of automatic instructions. 
Program 
A program is a is an executable software that runs on a computer. It contains compiled codes that 
run directly from the computer's operating system. 
Operating System 
The operating system (OS) is the software that communicates with the computer hardware on the 
primary level. No software can be run on the computer without the operating system. It serves as a 
user interface and helps allocating memory, processes tasks, accesses disks and peripheral. 
Command 
A command is a series of step by step instructions that helps the computer perform a specific 
action. 
CPU 
The central processing unit or CPU, also known as the microprocessor or processor is the brain of 
the computer. It helps execute instructions in a software program and helps retrieve instructions 
form the computer's memory, comprehending and executing instructions and helping direct the 
input and output of the computer. 
Desktop 
The computer monitor or the screen of the computer against which, the operating system and 
access application programs, files and documents are displayed is called the desktop. 
File 
The file is a unit for information storage that includes word-processor, spreadsheet, pictures, music, 
etc. Each file is differentiated with the help of a unique file name. 
Folder 
The folder is a unique system that helps in organizing the files, topics, programs and projects on the 
computer. The similar applications in a folder will be grouped together when an application 
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COMPUTER OPERATIONS  PACKAGES 
program is loaded. It is similar to organizing files on a shelf in your cabinet. 
Hard Drive 
The hard drive is the region where the information is stored and helps the computer to permanently 
retain and store the data. 
Hardware 
The computer system that comprises of a computer, that is, monitor, keyboard, mouse, printer, 
computer unit, scanner, etc. is known as the hardware. When the CPU is opened, the components 
that make a CPU are also the hardware. You can read and learn more on computer hardware 
basic information. 
Hyperlink 
An hyperlink is a program that helps one move from one web page to another. The text is 
underlined and the cursor that moves over this text document, takes the shape of a hand. This 
means there is a hyperlink added to the text and you can click on it to move over to another page 
or document. 
Internet 
The Internet is a world wide network that helps connect millions of users around the world to share 
and exchange data, information, opinions, etc. The Internet is not similar to World Wide Web 
(WWW). The WWW is a service that is provided on the Internet for the users. 
Monitor 
The computer monitor is defined as the computer screen or display unit. The monitor helps in 
displaying the user interface and programs. It is a way for the user to interact with the computer, 
using the keyboard and mouse. 
Mouse 
Do not be baffled, a computer mouse is a hand held device that helps the user move across the 
flat surface and help control the pointer on the screen. It is a very accessible device, as it helps 
one move faster across the screen and perform many tasks quickly. 
Keyboard 
The computer keyboard is the peripheral unit of the computer that helps in typing in the words and 
numbers along with the symbols and thus communicate with computer. In other words, it is the 
way, how you can feed in information that needs to processed into your computer. You can read 
more on computer keyboard shortcuts. 
RAM 
Random Access Memory or RAM is the temporary storage space in the computer that helps place 
information so that is can execute the program and instructions given. Once a program is closed, 
the data is removed from RAM. The amount of RAM helps in determining the number of programs 
that can be run. 
Browser 
The web browser is an application that helps render the source code of World Wide Web or web 
pages that can be used by the user. The information is rendered in understandable form for the 
user by the browser. The Microsoft Internet Explorer is an example of the browser. 
Peripherals 
The peripherals are the input devices that are connected to the machines. The keyboard, mouse 
and printer are computer peripherals. Some peripherals are important for the working of the 
machine and some are added components, without which one can work on the computer. 
Networks 
The network is a physical or logical construction that connects different computers together and 
helps them communicate. The computer networking is carried out through cabling or through 
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COMPUTER OPERATIONS  PACKAGES 
wireless networking. The best example is the Internet that helps sites to connect on different 
computers. 
Software 
The instructions that are provided to the computer with step-by-step actions that help executing a 
specific task is a software. A computer cannot function without a software. 
These were a few basic computer terms for kids that can be helpful for a beginner to understand 
the computer parts list. Computers have become a part and parcel of our daily lives, without 
which we cannot function. Man has become so dependent on the computer that a minor 
computer glitch can send life into a tizzy. One needs to learn using a computer, as much as he 
needs to learn how to read and write. Today, people breath software and eat hardware 
(hypothetically speaking). You do not want to be left out in this rat race of technically sound world. 
So begin by learning and teaching your kids these basic computer terms for beginners. 
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QUIZ 
A B C D 
1 
You have completed the document and want 
to make certain that you have not made 
spelling or grammar errors. 
Which button do you select? 
2 
Text is selected and you want to remove the 
selection from the active document and place 
it on the clipboard. 
Which button do you select? 
3 
You have made a change to the active 
document and want to make certain that those 
changes are saved. 
Which button do you select? 
4 
A phrase will appear several times in the 
document. To save time you have selected the 
phrase and want to copy it. 
Which button do you select? 
5 
The document had been checked for spelling 
errors, it has been saved, and now you are 
ready to print. 
Which button do you select? 
6 
A document which has been saved into a folder 
on your computer is to be opened so changes 
can be made. 
Which button do you select? 
7 
The document had been checked for spelling 
and has been saved. Before sending it to the 
printer you want to see how it will look. 
Which button do you select?
COMPUTER OPERATIONS  PACKAGES 
A B C D 
rmmakaha@gmail.com 145 
1 
Instead of striking the underline key fifteen 
times, you plan to draw a single line by 
clicking and dragging. 
Which button do you select? 
2 
You have drawn a line, and now want to 
change the color of the selected line. 
Which button do you select? 
3 
The last line you drew had an arrowhead at 
the wrong end. You want to change the 
arrowhead to the other end of the line. 
Which button do you select? 
4 
You created an object in a document and 
you want to tilt it at an angle. 
Which button do you select? 
5 
You have drawn a rectangle around a 
section of a flyer and want to change it to a 
dashed line. 
Which button do you select? 
6 
The heading of a flyer is just plain text and 
you would rather create special effects with 
text. 
Which button do you select? 
7 
You are going to draw a perfect circle on 
your document by holding down the shift 
key, clicking and dragging. 
Which button do you select? 
A B C D 
1 
You wish to call attention to a statement in 
your document by making the text bold. 
Which button do you select? 
2 
A flyer is to be prepared inviting parents to a 
performance. You want the headline to be 
centered on the page. 
Which button do you select? 
3 
You want to make sure that your instructions 
are clear and plan to place them in a
COMPUTER OPERATIONS  PACKAGES 
bulleted list. 
Which button do you select? 
rmmakaha@gmail.com 146 
4 
To call attention to a block of text, you want 
place a block of color behind the text to 
highlight it. 
Which button do you select? 
5 
Another way to call attention to a block of 
text is to place a border around it. 
Which button do you select? 
6 
A quoted block of text has been indented. 
You wish to continue the document but you 
need to undo the indent. 
Which button do you select? 
7 
You have made a birthday certificate and 
you want the student's name to be 
displayed in color. 
Which button do you select?

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COMPUTER OPERATIONS & PACKAGES NOTES & INTRODUCTION TO COMPUTERS

  • 1. rmmakaha@gmail.com COMPUTER OPERATIONS & PACKAGES rmmakaha@gmail.com
  • 2. COMPUTER OPERATIONS & PACKAGES rmmakaha@gmail.com 1 DEFINE A COMPUTER An electronic machine that works under the control of stored programs to accept, process output data/information for use by the operator. A device that accepts data, processes the data in accordance with a stored program, generates results, and usually consists of input, output, storage, and arithmetic, logic, and control units. A functional unit that can perform substantial computation, including numerous arithmetic operations or logic operations, without human intervention during a run. It is an electronic device/machine that accepts data(raw facts figures) asinput and processes (works on it) to produce information(data converted tomeaningful form) as output. A computer performs a number of functions: • Input (Data) The computer accepts data from outside for processing. Input is the raw information entered into a computer from the input devices. • Processing The computer performs operations on the data that it holds internally. Processing is the operation of data as per given instruction. It is totally internal process of the computer system. • Output The computer produces information for external use. Output is the processed data given by computer after data processing. Output is also called as Result. We can save these results in the storage devices for the future use. • Storage The computer stores data before, during and after processing. • Communication The computer can send or receive data to or from other computers when it is connected on a network The computer is made up of hardware, software and peripheral devices. Hardware- refers to the tangible, physical and mechanical components of a computer. Software- refers to the intangible computer components, which are the programs or instructions of the computer. Everything that a computer does, it acts under instructions written out as computer programs. The hardware needs these instructions to function Computer program: • A set of instructions, written in a specific programming language, which a computer follows in processing data, performing an operation, or solving a logical problem. See also software. • A computer program is a set of statements or instructions to be used directly or indirectly in a computer in order to bring about a certain result. NB: Software alone is useless, so is the hardware. The two are inseparable. Peripheral Devices- These are devices that are external (not part of the computer) but can be connected to a computer. They are not essential for the functioning of the computer but can be
  • 3. COMPUTER OPERATIONS PACKAGES connected to the computer for specific reasons. Examples are scanners, modems, printers, speakers, digital cameras, etc. rmmakaha@gmail.com 2 DATA PROCESSING Used specifically, data processing may refer to a discrete step in the information processing cycle in which data is acquired, entered, validated, processed, stored, and output, either in response to queries or in the form of routine reports; the processing is the step that organizes the information in order to form the desired output. Used in a more general sense, data processing may also refer to the act of recording or otherwise handling one or more sets of data, and is often performed with the use of computers. The word data is commonly used to mean “information” and often suggests large amounts of information in a standardized format. Data may consist of letters, numbers, equations, dates, images, and other material, but does not usually include entire words. CATEGORIES OF DATA PROCESSING Data is processed to get the required results. Different operations may be performed on data. Therefore, data processing is defined as: A sequence of operations on data to convert it into useful information is called data processing. The important operations that can be performed on data are: • Arithmetic and logical operations on data to get required results. • To send and receive data from one location to another. • Classification of data. • Arranging data into a specific order etc. The data processing is divided into three categories or levels. 1. Manual Data Processing In manual data processing, data is processed manually without using any machine or tool to get required result. In manual data processing, all the calculations and logical operations are manually performed on the data. Similarly, data is manually transferred from one place to another. This method of data processing is very slow and errors may occur in the output. In Zimbabwe, data is still processed manually in many small business firms as well as government offices institutions. In manual data processing data is processed manually. No machine or tool is used. All the calculations on data are performed manually. This is a slow method and errors may occur. This is an old method. It was used before the invention of calculators. But data is still processed manually in many small shops.
  • 4. COMPUTER OPERATIONS PACKAGES Example: A book seller (a small book shop) records his daily transactions manually. He prepares bills by pen, paper and carbon paper (no doubt, brain is the main data processor in this case). At the end of day he will use carbon copies made on a particular date to know how many books he sold and how much income he got. rmmakaha@gmail.com 3 2. Mechanical Data Processing In mechanical data processing, data is processed by using different tools like calculators or other mechanical devices. This method of data processing is faster and more accurate than manual data processing. Mechanical data processing is more accurate than manual. Calculators, computer programs and other devices are used on the data however someone still has to step in between operations. In mechanical data processing data is processed with the help of devices or machines. These machines that help the people in data processing may be calculators and type writers etc. Obviously, this method is faster easier and more accurate than manual data processing. Example: Book seller can use a calculator to speed up his data processing system. There will be a less chance of errors in calculations. Bill calculations will be much more faster with a calculator and easier too. 3. Electronic Data Processing It is the modern technique to process data. The data is processed through computer. Data and set of instructions are given to the computer as input and the computer automatically processes the data according to the given set of instructions. The computer is also known as electronic data processing machine. This method of processing data is very fast and accurate. Now-a-days, the data is processed and analyzed through computers. For example, the results of students are prepared through computer; in banks accounts of customers are processed through computers etc.
  • 5. COMPUTER OPERATIONS PACKAGES It is the latest and fastest method of data processing. Data is processed with the help of computer. First of all, data and set of instructions are given to the computer. Computer gives output results after processing the data according to instructions. This method of data processing is very fast and accurate. Electronic data processing is used in banks and business firms, Government offices, colleges, schools, universities, businesses and other institutes. Electronic data processing is being used in almost every field of life. Example: Suppose there are 800 students in a college. There is a manual library system in this college. If we want to know which students have not returned books since one year? We will have to search registers for 800 students’ record. But computer can do this job within seconds. In short, we can say that: Electronic data processing: i) is more fast ii) is less time consuming iii) can process large amounts of data easily iv) can present information in more attractive way v) will give 100 % error free results, if input and instructions are accurate. rmmakaha@gmail.com 4 THE DATA PROCESSING CYCLE The data processing cycle is the order in which data is processed. There are four stages:- After collecting data, it is processed to convert into information. The data is processed again and again until accurate result is achieved. This is called data processing cycle. Data processing cycle involves following three basic activities:
  • 6. COMPUTER OPERATIONS PACKAGES rmmakaha@gmail.com 5 1. Input 2. Processing 3. Output 1. INPUT It is the process in which collected data is given to computer after converting into binary form. Input step can be further divided into following steps: i) Planning Here objectives of data processing are defined. For example, in examination system, objective is to process student examination data to get result cards. ii) Data Collecting Here data is collected. Data is the raw material for data processing. This must be accurate for getting accurate results. iii) Input Here data is entered into computer. iv)Verification Here collected data is verified to determine whether it is valid for processing. For example marks must be in numeric form. v) Coding Data is stored in computer in binary form. Here data is converted (or coded) into computer readable (binary) form. 2. PROCESSING Now data is ready for processing. We process collected data to convert into information. Some important activities in processing are as following: i) Data Classification Here data is classified into different groups or sub-groups. So that it can be handled easily and separately. For example if we collect data about students of a college we will divide them into D.Com and B.Com class groups. ii) Data Sorting Here data is arranged in some order. So that it can be accessed quickly. For example we can sort student data by Roll number or name. iii) Data Calculation/Processing
  • 7. COMPUTER OPERATIONS PACKAGES Here arithmetic and logical operations are performed on data to get the required result. For example total marks of each student are calculated. rmmakaha@gmail.com 6 3. OUTPUT After completing the processing, output is received. Output step involves following steps: i) Testing The results are tested to find if they are according to requirements. And any errors are removed. If results are not satisfactory then we repeat above-mentioned steps again and again until the accurate results are found. ii) Summarizing Huge results are summarized to make them short and precise. iii) Storing results The results are stored properly on secondary storage devices for future use. iv)Output the result Here output is produced as softcopy on screen or as hard copy as printout. Information is sent to different places as needed. v) Feed Back In this step we take comments from users about output results. If results are not satisfactory then we repeat above-mentioned steps again and again until the accurate results are found. What is the Information Processing Cycle? If one has to look at the information processing cycle diagram, he will see that there are four events in the sequence of events. The sequence of events, which make up the cycle are: Input Processing Output Storage
  • 8. COMPUTER OPERATIONS PACKAGES In some of the events, certain sub-events can also be added. Without wasting any more time we will turn towards the cycle in detail. Input This is the first event in the cycle. This stage involves collection of data from the outside or also from within the system. One can break this stage into three more stages, namely acquisition, data entry and validation. After the data has been acquired from the source, it is entered into the current system, upon which the data is validated, so that correct results are given at the end of the cycle. The input devices are many. The commonly used input devices are computer keyboard, bar code readers, scanners, output from another system, etc. Processing In this stage the computer processes the minutest details entered. This processing makes the data entered usable. If the computer was not to process the data, it would not be of any use and it would also be a big mess of data. For example, if the spreadsheet was not to process the data, then the data in the spreadsheet would only be a mess of numbers. The spreadsheet is a program which gives the data out back to the user in the usable form. The system used for processing, along with the data entered will decide the kind of output, which the user will get. Output If you have to look at the diagram of information processing cycle, the step after processing is the output stage. The processed information is now transmitted to the user. This stage can also be further divided. After processing the data, there can be further interactive queries asked or routine reports can be given. There are different forms in which the output can be given to the user. There can be print report, which may be given to the user. The output can also be given in the form of audio, video as well. In some cases, the results may only be displayed on the computer monitor. Storage After the data has been processed, along with the output to the user, the data is also stored. Different computer storage devices can be used for the same. Some of the commonly used data storage methods are disk storage, tertiary storage, etc. Storing the data also serves another purpose. You will not have to repeat the entire cycle again. Often the storage is done in both digital as well as hard copy format. At the same time, backup of the digital format is also maintained, which can be retrieved in case of system crash. The most important advantage of this cycle is that the information is processed quickly. At the same time retrieving the data is an easy task as well. The processed information can further be passed unto the next stage directly in case the need be. The necessary data is stored, which helps in avoiding duplication of data as well as time. ATTRIBUTES OF GOOD INFORMATION rmmakaha@gmail.com 7 Quality Required Commentary Relevant The information obtained and used should be needed for decision-making. it doesn't matter how interesting it is. Businesses are often criticised for producing too much information simply because their information systems can do it. A good way of ensuring relevance is to closely define the objectives of any information reports. Another way to improve relevance is to produce information that focuses on exceptions - e.g. problems, high or low values, where limits have been exceeded. Up-to-date Information needs to be timely if it is to be actioned. For example, the manager of a large retail business needs daily information on how stores are performing, which products are selling well (or not) so that immediate action can be taken. To improve the speed with which information is produced, businesses usually need to look at upgrading or replacing their information systems.
  • 9. COMPUTER OPERATIONS PACKAGES Accurate As far as possible, information should be free from errors (e.g. the figures add up; data is allocated to the correct categories). The users of information should be informed whenever assumptions or estimates have been used. Accruate information is usually a function of accurate data collection. If information needs to be extremely accurate, then more time needs to be allocated for it to be checked. However, businesses need to guard against trying to produce perfect information - it is often more important for the information to be up-to-date than perfect. rmmakaha@gmail.com 8 Meet the needs of the User Users of information have different needs. The managing director doesn't have time to trawl through thick printouts of each week's production or sales listings - he or she wants a summary of the key facts. The quality control supervisor will want detailed information about quality testing results rather than a brief one-line summary of how things are going. It is a good idea to encourage users to help develop the style and format of information reporting that they require. Easy to use and understand Information should be clearly presented (e.g. use summaries, charts) and not too long. It also needs to be communicated using an appropriate medium (e.g. email, printed report, presentation. Businesses should also consider developing templates which are used consistently throughout the organisation - so that users get used to seeing information in a similar style. Worth the cost Often forgotten. Information costs money. Data is costly to collect, analyse and report. Information takes time to read and assimilate. All users should question whether the information they recieve/have requested is worthwhile Reliable Information should come from authoritative sources. It is good practice to quote the source used - whether it be internal or external sources. If estimates or assumptions have been applied, these should be clearly stated and explained. 1) Valid 2) Fit for use 3) Accessible 4) Cost effective 5) Understandable 6) Time DATA Relationship between Data and Information Data is raw information a collection of facts from which conclusions may be drawn; statistical data INFORMATION Data that has been processed to add or create meaning and hopefully knowledge for the person who receives it. Information is the output of information systems. Organized data which is understood to have significance and meaning Methods of data collection {see Systems Analysis Design} Questionnaires Observation Sampling Interviews Written documents research MAKE NOTES ON: Verification o The act of reviewing, inspecting, testing, checking, auditing, or otherwise establishing and documenting whether items, processes, services, or documents conform to specified requirements. o An effort to test the accuracy of the questionnaire response data. The concern is uniquely with data accuracy and deals with neither the reliability nor the validity of measures. Validation
  • 10. COMPUTER OPERATIONS PACKAGES o The process of evaluating software at the end of the software development process to ensure compliance with software requirements. The techniques for validation are testing, inspection and reviewing. o Determination of the correctness of the products of software development with respect to the user needs and requirements. rmmakaha@gmail.com 9 BENEFITS OF COMPUTERS With the advent of new technology, various processes have been very dependent with automation. As the years go by, more and more inventions are introduced in the market and in the society all for one purpose - convenience. Let us tackle for instance two of the most influential aspects of this modern world; the societal and the entrepreneurial feature. These two have been greatly influenced by the advancements that are continuously taking place. With that said, a number of essential advantages are becoming more evident in these two facets. To further draw a clearer picture on the benefits of computers on each of the mentioned aspect, here are brief descriptions of each. Business Multitasking - The modern multimedia options enable entrepreneurs to work various tasks all at the same time. Workers in the offices can use the DVD-ROM while installing Printer Cartridges and running a scan thus making workload easier and more convenient. With such, the need for an outsourcing company would not be essential because all the tasks can be addressed by majority of the manpower available. Cost-effective - These computers have allowed companies to cut costs on payroll and individual office equipment. Because of the efficient and fast outputs coupled with less expenditures on operations, revenues are then maximized. Good examples for this benefit are the email messaging that lessens postage costs and video conferencing that decreases travel allowances for employees. Increased access to the market - Because of the Internet, businesses have opened their doors to various opportunities all around the globe. For those selling goods, then customers can readily purchase them over the Web thus resulting to an increase in the sales of the firm. Also, advertising strategies are well utilized because by just simply posting a good multimedia scheme over the Web, firms can readily maximize their marketing plans. Organization- Different types of software are utilized to store a wide array of documents that must be kept confidential for years. With the help of computers, storage and retrieval of files are easily done with just a click of the mouse. Those are the benefits that businesses are enjoying from the various innovations in computers now. Further, here are the societal advantages. Education edge- Nowadays, PC's enable students to search from a wide range of online resources. Hence, they can save time on looking for the best Internet source that can answer each of the queries. Instead of spending so much time looking for books, then this could answer the worries for students who want to hasten their tasks. Also, a new trend in education is online teaching. Through the Web, people can freely enroll in a specific course provided that you get to pay the fees on the specified date. This scheme can be very helpful for individuals who want to get a degree yet are to busy to get into the usual classroom setting. Communication benefit- Social networking sites, chat, and video conferencing sites are accessible because of computers. People across the globe can now talk to their loved ones in real time with
  • 11. COMPUTER OPERATIONS PACKAGES the help of these gadgets. What is good about this communication option is that it is more cost effective than the usual telephone. By embracing such, people can now deliver messages and create a copy of that using quality printer cartridge in just a second. Job opportunities- These gadgets open up a wide array of workload for people. That is, experts are needed in software and hardware maintenance and checks. With the increasing demand for these professionals, unemployment is then lessened at a considerable percentage. Home Entertainment- During weekends, you may utilize your personal computer to watch films using its DVD-ROM. Aside from this, you may as well play games all throughout the day. You can simply install a variety of files that you can use for the whole day of indoor fun. From the latest TV shows to the more modern games, you can have them in your CPU just minutes. Those are few of the numerous benefits of personal computers in our everyday lives. Knowing each of those points will certainly allow you to see the importance of those gadgets in almost all processes that are taking place every day. With this obvious dependence, it is also but essential to ensure that each of the systems are working properly. This is because a single defect inside the CPU could mean serious impairment. Hence, the specialists in repairs and maintenance can be tapped for their expertise. rmmakaha@gmail.com 10 ADDITIONAL Without computers, there would be no Internet. Computers and the internet helped create a global community where it is possible to instantly communicate with anyone around the globe. You aren't just stuck being exposed to only those in your own community or country. Various online knowledge sources including online encyclopaedias, open vast amounts of information to people all over the world. This can even aid someone doing anything from a simple homework assignment, to a complex research paper. In the home, you can pay your bills online, without having to write a check or placing the bill in a postage envelope. No chance of the payment getting lost in the mail, and no need to worry about being assessed a late charge - as the bill has been paid and confirmed. People now listen to music, get up to the minute live news reports, play games, watch movies, and even watch television shows they might have missed. You can buy products online that may not be available in your local shops. Computer chips are used in many many things, including the portable cell-phone. And the internet led to Twitter, which was used recently by Iranians keeping communication and coordination active against an oppressive regime. In the business world, computers are used in every operation, function and activity of an organization. This had led to improved productivity, greater collaboration, major improvements to information management. Computers help scientists calculate things faster and learn more about the world and universe. In addition, this helps things get invented, like a video game system. Computers are used heavily to improve accuracy, flexibility of planning, and speed in Engineering work. Civil Engineering - Autocad and WaterCad.Mining engineering - Surface Deformation Prediction Software.Mechanical engineering - SolidCad. Electrical Engineering - electric cycle programs. In the medical community, computers led to improved Hospital care. So in a sense, computers have even helped extend the average lifespan of human beings.
  • 12. COMPUTER OPERATIONS PACKAGES rmmakaha@gmail.com 11 LIMITATIONS 1. They are expensive. 2. If you have little knowledge of them, it is easy to get in a lot of trouble and quite literally destroy your computer. 3. Depending on the OS and software/hardware installed, they can be difficult to maintain. 4. If you have the internet and don't have an Anti-Virus program, or at least an Anti-Spyware program, surfing the web can ruin your day. 5. Nothing lasts forever. Computer disadvantages are as follows; Violation of Privacy, it is crucial that personal and confidential records stored in computers be protected properly. Impact on Labor Force, although computers have improved productivity and created an entire industry with hundreds of thousands of new jobs, the skills of hundreds of thousands employees are replaced by computers. Health Risks, prolonged or improper computer use can lead to head injuries or disorders. Computer users can protect themselves from health risks through proper workplace design, good posture while at the computer, and appropriately spaced work breaks. Impact on the Environment, Computer manufacturing processes and computer waste are depleting natural resources and polluting the environment. MAJOR COMPONENTS OF A COMPUTER SYSTEM CPU The CPU consists of the ALU CU KEY Data Instructions Command Flow Control unit-issues commands to computer elements interpret stored instructions A. L.U. performs arithmetic logic operations Output Unit Information after processing Main Memory-Holds data instructions results ofprocessing -RAM Input Unit Data instructions Backing/Auxiliary Storage- supplements the main storage.
  • 13. COMPUTER OPERATIONS PACKAGES DESCRIBE THE FUNCTIONS OF EACH COMPONENT. Main memory Auxiliary or backup storage Stores programs and data while computer is running for current use Store data or programs for later use Main memory is fast and limited in capacity Slow and capacity vary Cannot retain information when the computer is Non volatile switched off - Volatile Memory directly connected to the CPU - not portable Portable- can be transported from one machine to another. Primary storage Secondary storage PROVIDES FAST ACCESS ACCESS IS SLOW Temporary Permanent Computer cannot do or work without Can do or work without rmmakaha@gmail.com 12 PROCESSING DEVICE The only processing device on a computer is The Central Processing unit known as the CPU. It is the main part of the computer as all other devices are built around it. It can be referred to as the heart or brain behind the computer. Functions of the Central Processing Unit (CPU) a) It interprets the instruction in the program according to the type and sequence of processing operations that are to be performed on input data. b) Performs the varied arithmetic and logic operations that are necessary to convert input data into output information. c) Stores intermediate results of data being processed on its registers. d) Directs or controls output to all other devices (input, output, auxiliary storage units), telling each what to do and when to do it. CPU COMPONENTS It consists of the control unit (CU) and Arithmetic and Logic Unit (ALU). In most computers the two components - CU and ALU units - are combined in a unit called the microprocessor (CPU). The Control Unit The Control Unit manages input/output to and from the main memory and to and from auxiliary storage units and output devices. It interprets instructions in their sequence,It determines what is to be done to follow the instruction and, transmits to the appropriate device directions specifying the work to be done. For example, it advises each input device what data to transfer, when to transfer it, and when to send the data. It arranges for data to move from the main memory to the ALU and spells out the calculating and logic operations that are to be performed, and then arranges to send the processed results to main storage or to an output device for printing or display. The ALU The Arithmetic Logical Unit has 2 functions i.e. to perform calculations and logic operations at a fast speed (measured in nanoseconds, i.e. billionths of a second). It consists of registers (special storage locations to hold the data to be processed), and an accumulator to store intermediate results of operations. Logic operations compare values for greater, smaller or equal. CPU speed
  • 14. COMPUTER OPERATIONS PACKAGES The CPU speed is measured in Megahertz (MHz) being millions of instructions that can be executed per second (MIPS). Each computer has specified, the processor speed. rmmakaha@gmail.com 13 INPUT DEVICES These are some devices that feed data into the computer for processing. Some examples include:- 1. KEYBOARD 2. MOUSE 3. TRACKBALL 4. LIGHT PEN 5. TOUCH SCREEN 6. MODEM 7. SCANNER 8. MICROPHONE 9. BAR CODE READER 10. DIGITAL CAMERA 11. VIDEO DIGITISER 12. MAGNETIC INK CHARACTER RECOGNITION (MICR) 13. MAGNETC STRIPS OR STRIPES READER 14. KEY TO DISK 15. GRAPHICS TABLET 16. OCR 17. OMR 18. VOICE RECOGNITION SYSTEM Storage devices can be used as input devices a) KEYBOARD The keyboard is an input device with an arrangement of keys, like those on a typewriter, and an additional set of keys that fall into 5 basic categories: 1. Function keys- keys form the first row of keys. They perform special operations in applications e.g. F7 activates Spell Checking Program in word processing and F1 activates the Help facility in any application. 2. Alphanumeric keys (like those on typewriter) are arranged in a QWERTY series. First is a row of numbers with some characters like %^*()@!~ above them, then letters of the alphabet, the spacebar at the bottom, the Shift key on both the left and right side of the Spacebar. 3. Numeric keypad- serves 2 functions. At the top of the keypad is the NumLock key, which locks the keypad into Number mode when, pressed. When in Number mode, the keys function as number keys arranged like a standard calculator, otherwise it is in Cursor control mode, which allows you to move the cursor up, down, forward or backward by pressing the appropriate arrow key. When in cursor mode you can also use the home, page up, page down, end, delete and insert keys from Num Lock pad. 4. Cursor control keys are the arrow keys as well as Home, End, Ins, Page Up etc. Their major function is to place the cursor in an appropriate position for reading, appending or editing text. 5. Combination keys are the Shift Ctrl andAlt keys. On their own they are ineffective but combined with other keys they work. E.G. The Shift key, can be used to type to type the $ sign (you would keep Shift pressed as you press the $ sign key once). b) MOUSE
  • 15. COMPUTER OPERATIONS PACKAGES The mouse is both input and pointing device. It is a hand held device with a rotating ball (trackball) underneath and Left Right (the blinking item on your screen) around the screen and to click on objects. The trackball is made from a ball in a socket, which is used to move the cursor on a screen. The cursor moves in the direction the ball moves as it is rolled. c) JOYSTICK ) buttons, which enable the user to move the cursor he device. A leverinputdevice that can be moved in many directions, The joystick is anInput device e.g. Up, Down, Left or Right. It is normally used with computer games to control the movements of objects on the screen. d) LIGHT PEN This is an Inputdevice. An electricaldeviceused with a monitor ordinary pen. One writes on a monitor with it and it senses the light from the position on the screen and transmits the information to the computer. e) TOUCH-SENSITIVE SCREEN/ TOUCH PAD Input deviceused in public information kiosks point of interest to get what (s Touchpad A small pressure- and motion move the mouse pointer. When you move your finger across the pad, the mouse pointer on the screen moves in the same direction. A touchpad is an alternative to a mouse. A touchpad is operated by using your finger and dragging it across a flat surface; as yo move your finger on the surface, the mouse cursor will move in that same direction, and like most computer mice, the touchpad also has two buttons below the touch surface that enables you to click like a standard mouse. f) SCANNER – Input device It works like a photocopier but copies an image from text to computer mode need for OCR (Optical Character Recognition) software to change the text into digital form, and to be able to modify the scanned image. g) MICROPHONE rmmakaha@gmail.com monitor. It has the shape of an SITIVE kiosks. Theuser simply touches the screen at the s) he wants. motion-sensitive area on a portable computer that you can use to ks 14 you mode. There is
  • 16. COMPUTER OPERATIONS PACKAGES This is Input device. This is words are into digital mode for storage. The sound can be played back. h) DIGITAL CAMERA used in conjunction with voice recognition programs. It converts This is Input device. It works like a standard camera except that it does not use photographic film. The images are recorded digitally in the camera’s memory. Images are transferred onto the computer, and can be printed. MORE INPUT DEVICES 1. KEY TO DISK- An early stand-computer -alone data entry machine that stored data on magnetic entry. The key to disk machine was the successor to the key-to-tape machine, which was the first major breakthrough in data entry since the punch card. 2. BARCODE READER Barcodes are different groups of vertical bars that can be read by an optical Barcodes are printed on nearly every product that you can buy. Shops use barcodes because they are cheap to produce and very durable. 3. CONCEPT KEYBOARD This is a flat board that contains a grid of buttons. Each button can be programmed to follow instructions. An overlay sheet is placed on the grid with an explanation for each button. They are used in primary schools with young children. Many mod restaurants have overlays with either a description or picture of the meals that are available to make ordering easier. 4. DIGITAL CAMERA A digital camera allows you to take pictures and to store a digital photographic image that can be read by a computer. You can then transfer the images directly from your camera on to your computer. 5. GRAPHICS TABLET This consists of a flat pad (the tablet) on which the user draws with a special pen. As the user draws on the pad the image is created on the screen. Using a graphics tablet a designer can produce very accurate on 6. MICR (MAGNETIC INK CHARACTER READER) Magnetic ink characters are the strange looking numbers that appear at the bottom of cheques. These characters are used because they are very difficult to forge or damage. Banks use MICR to read the numbers from the bottom of cheques to obtain account numbers and bank sort codes. 7. MAGNETIC STRIP (OR STRIPE) READER Magnetic strips are built into many plastic cards such as point cards and personal identity cards. The magnetic strip on the back of the card can hold the personal details of the card owner and, with the necessary PIN, will allow access rmmakaha@gmail.com modern fast food on-screen drawings. data cheque guarantee cards, cash 15 disk for scanner. ern such as cash-point
  • 17. COMPUTER OPERATIONS PACKAGES to secure information e.g. bank account details input into a computer system by a reader. details. Data stored on the strip is scanned and 8. MIDI (MUSICAL INSTRUMENT DIGITAL INTERFACE INTERFACE) A MIDI system allows you to attach a musical instrument to your computer, for example a musical keyboard. You can then store a the computer play it back to you. 9. OMR (OPTICAL MARK READER musical sequence on a computer and then have READER) An OMR reads marks made by pencil on a printed form into the computer. OMR systems are suited to reading pre selection sheets and multiple OMR processing is popular for tests, where students receive a special card containing several empty circles and a packet that contains the questions and possible answers to each of the questions. The student must complete the test by using a pencil to fill in each blank circle with what he or she believes is the correct answer. For example, if the answer is B, the student would have to fill in the B Circle in order to get the answer 10. SCANNER pre-printed forms and check-boxes such as National Lottery number multiple-choice exam papers. Hardware input device that allows a user to take an image or text and convert it into a digital file, allowing the computer to read or display the scanned object. A scanner is commonly connected to a computer USB, Firewire, Parallel, or SCSI port. a cheap and common way of getting images into a computer. They can also be used with OCR (Optical Character Recognition) softw 11. TOUCH SCREEN A touch screen is a special type of crossing the screen. When the screen is touched (usually to choose an on rmmakaha@gmail.com correct. Scanners software to scan in text. VDU, which has a grid of light beams or fine wires criss on-screen option), 16 . tional are now , criss-screen
  • 18. COMPUTER OPERATIONS PACKAGES the computer senses where you have pressed. Due to the vast amount of information they can store, touch screen operated computers are generally used in the provision of public information and are found in places such as airports. rmmakaha@gmail.com 17 12. VIDEO DIGITISER A video digitizer takes an image from a video camera or television and converts it so that it can be used by, and stored on, a computer. Video sequences captured using a video digitizer is often used in multimedia presentations. 13. VOICE RECOGNITION SYSTEM A microphone is used with a voice recognition system. This can be used with a word processing program to enter text. It can also be used as part of security systems - only certain digitally stored voices have access. TEXT INPUT DEVICES • Chorded keyboard ,GKOS keyboard ,Keyer ,Telegraph key (~20 WPMMorse code) • Vibroplex (30–80 WPM Morse) ,Keyboard, Typing ,Computer keyboard • Handwriting recognition ,Optical character recognition ,Speech recognition POINTING DEVICES • Light pen,Light gun,Cyberglove ,Touch screen ,Head pointer ,Eye gaze/eye tracking • Computer mouse ,Trackball ,Touchpad ,Pointing stick ,Graphics tablet (or digitizing tablet) ,Stylus GAMING DEVICES • paddle, Power Pad, Joystick ,Gamepad (or joypad) IMAGE, VIDEO INPUT DEVICES • Digital camcorder ,Webcam, Digital video recorder,Image scanner • 3D scanner ,Digital camera AUDIO INPUT DEVICES • Microphone (see also speech recognition) ,Digital audio recorder ,Digital dictaphone OUTPUT DEVICES 1. LOUD SPEAKER Allows a user to hear sounds and music from the computer provided the system has installed a sound card. 2. MODEM An Input/ Output electronic device with circuits which changes data to be transmitted from its machine form (digital form) into a form suitable for transmission over the telephone line (analogue form). At the receiving end it converts data vice-versa. It is only necessary when one needs to communicate information over a long distance and when connected to the internet. 3. HEADPHONES
  • 19. COMPUTER OPERATIONS PACKAGES Headphones give sound output from the computer. except they are worn on the ears so only one person can hear the output at a time 4. PLOTTERS A plotter can be used to They are usually used for Computer Aided Design ( Manufacture (CAM) applications such as Plotters: How it works: • A drum plotter the surface of a sheet of paper. • One high precision motor moves the pen from side to side. • Another high precision motor moves the paper backwards and forwards. • An electromagnet lifts and drops different coloured ink pens onto the paper to draw lines. • A flat • pen in the X direction and one to move it in the Y direction. • The paper does not move. Suitable uses: • Plotters are restricted to line drawing and can only create a solid region of colour by drawing a number of close, regular lines. • Plotters are often used in science and engineering applications for drawing building Advantages: • They are standard printers. rmmakaha@gmail.com They are similar to speakers, produce high quality, accurate, A3 size or bigger drawings. CAD) and Computer Aided printing out plans for houses or car parts. prints by moving a pen sideways over flat-bed plotter uses two high precision motors, one to move the plans, printed circuit boards and machine parts. accurate and can produce far larger printoutsthan 18 ) than
  • 20. COMPUTER OPERATIONS PACKAGES Disadvantages: • Slow and relatively expensive compared to printers. • They cannot print raster (photographic) images. • They can only fill solid blocks of colour using closely hatched lines. rmmakaha@gmail.com 19 5. SPEAKER A speaker gives you sound output from your computer. Some speakers are built into the computer and some are separate 6. VDU (Visual Display Unit) The VDU is output device. It displays images and text in colour or black and white as it. It displays results of processing. It is also called a monitor. 7. PRINTERS It produces output on paper i.e. hard copy or on other print-key media. The 2 types of printers are impact and non-impact. Impact printers The printing device being a series of pins have a direct impact on the paper. The pins form characters on the paper by pressing a printing element and an inked ribbon against paper. An example of such a printer is the Dot Matrix. The printers are reasonably fast, inexpensive and can produce both text and graphics. They also accommodate various paper sizes but are however noisy. Non-impact printers These are quieter printers and examples include LaserJet and inkjet printers. The Laser printers are a more popular choice for business use. They use a printing technique similar to that used in a photocopying machine. A laser beam is used to form an image onto the paper using toner. The print quality is high. Lasers are fast, and quiet. They print graphics but are more expensive. The ink-jet printers are mainly colour printers which mix ink depending on the image colour and spray it onto the paper. The toner has the 4 basic colours. They are slow, expensive and have a high print quality. What is the difference between impact and non-impact printers? Impact Non impact Makes noise when printing Quiet printers Print head makes contact with the paper No contact creates an image without striking a ribbon against the paper.Creates images on a surface without contacting it. Strike ribbon against the paper Use a laser beam which form an image onto paper using toner Slow printer Fast printers Use ribbons or ink Use toner Has too many moving parts hence unreliable Has fewer moving parts hence they are reliable. Impact printers are relatively inexpensive, and the cost of printing is also low because ink ribbons are inexpensive. Very expensive computers Give two advantages of non-impact printers over impact printers.
  • 21. COMPUTER OPERATIONS PACKAGES Have high print quality They are fast and do not make noise They are reliable because they have less moving parts See above [non impact section] Give three examples of impact printers three examples of non-impact printers. Impact printers Non impact printers Dot matrix Laser Daisy wheel printers Inkjet Line printers LED Chain printers Thermal Magnetic Electrostatic Xerographic rmmakaha@gmail.com 20 NON-IMPACT PRINTERS 1 - Laser printers: How it works: • These print individual pages and work in a similar way to photocopiers. • A drum is charged to match the image and powdered ink (toner) sticks to the surface. The toner is then transferred to the paper and fixed by heat and pressure. • A school or business printer would have a typical speed of 10 to 20 pages per minute (ppm). Suitable uses: • Common wherever fast, high quality printing is required. Disadvantages: • Non-colour laser printers are more expensive than ink-jet printers (but the difference is narrowing). • Colour laser printers are considerably more expensive. (but their speed and high quality output means they are becoming more popular). Advantages: • They are quiet and fast and produce high quality printouts. • Running cost are low because although toner cartridges are expensive to replace, they last a long time. Laser printer - A type of printer that utilizes a laser beam to produce an image on a drum. The light of the laser alters the electrical charge on the drum wherever it hits. The drum is then rolled through a reservoir of toner, which is picked up by the charged portions of the drum. Finally, the toner is transferred to the paper through a combination of heat and pressure. Advantages -Monochrome or four color -High-quality print -Capable of printing an almost unlimited variety of fonts -Quiet operation Disadvantages -Color laser printerstend to be about five to ten times as expensive as monochrome -Cannot print on multiple-copy paper
  • 22. COMPUTER OPERATIONS PACKAGES 2 - Ink-jet printers: How it works: • The print head contains tiny nozzles through which different coloured inks can be sprayed onto the paper to form the characters or the graphic images. • The ink is forced out by heat or by tiny piezoelectric crystals which change shape when an electric current is applied across them. Suitable uses: • A popular choice for home use where small amounts of printing are done and photographic quality colour printing is needed. Disadvantages: • The ink cartridges can be expensive so running costs can be high. • The printing speed is slow compared to a laser printer. Advantages: • These printers are relatively inexpensive and produce high quality black and white or photographic quality borderless colour printing. Ink-jet printer - A type of printer that works by spraying ionized ink at a sheet of paper. Magnetized plates in the ink's path direct the ink onto the paper in the desired shapes. Ink-jet printersare capable of producing high quality print approaching that produced by laser printers Advantages -Inexpensive way to print full-color document -Easily portable due to smaller mechanical parts than laser printers -Quiet operation Disadvantages -Slow output -Require a special type of ink that is apt to smudge on inexpensive copier paper -Cannot print on multiple-copy paper 3. Thermal transfer printers- A type of printer that applies heat to a ribbon and the image or barcode is then transferred to labels or tags. This technology produces a higher quality, longer lasting image on the tag or label. Advantages -1 to 2 years media shelf life -Media is not heat sensitive -Medium to high image quality -Wide range of available types -Recommended for industrial use Disadvantages -Special ribbons required -Average operational cost -Cannot print on multiple-copy paper -Single-pass ribbons only 4. Direct thermal printers - A type of printer that applies heat directly to specially treated paper, labels or tags to form the image or barcode. rmmakaha@gmail.com 21 Advantages -No ribbon required -Low operational cost Disadvantages
  • 23. COMPUTER OPERATIONS PACKAGES -Short media shelf life -Very heat sensitive media -Limited image quality -Limited number of available types -Not recommended for use in industrial, outdoor, or harsh environments -Cannot print on multiple IMPACT PRINTERS multiple-copy paper 1 - Dot matrix printers: How it works: The print head travels from side to side across the paper and is made up of numerous pins which are pushed out to form the shape of each character The pins hit an ink ribbon against the paper so the characters are printed out. The paper is usually continuous with holes down each side and perforations so the pages can be easily separated by tearing. Because the pins make an impact against the paper the characters can be printed through several layers of self self-carbonating paper to produce duplicate copies. Suitable uses: • Limited to situations where duplicate copies are needed and the quality is not too important. • Typical uses might be in warehouses where duplicate copies of orders need to produced quickly and cheaply. Disadvantages: • The printing quality is low - these printers produce low to medium quality black and white printing and can only print low resolution graphics. • Because of the impact of the pins against the paper, these printers can be quite noisy noisy. Advantages: • The purchase cost is low • They can print fairly quickly, particularly if you remember that multiple copies are being pri printed in one print run. robust and can operate in harsh environments. • They are • If several sheets of self and the running costs are very low. self-carbonating paper are placed into the printer then rmmakaha@gmail.com 22 ,
  • 24. COMPUTER OPERATIONS PACKAGES the impact will produce duplicate copies. Dot-matrix printer- A type of printer that produces characters and illustrations by striking pins against an ink ribbon to print closely spaced dots in the appropriate shape. Advantages -Can print to multi-page forms- -Moderately priced -Multi-pass ribbons (saves money) Disadvantages -Noisy operation -Low-quality output -Slow print speed -Multi-pass ribbons (decrease in quality with each pass) rmmakaha@gmail.com 23 2. Daisy wheel Printers • Round disk found on older computer printers t hat extends a portion of the wheel making contact with ink ribbon that makes contact with paper creating the character. This procedure is repeated for each key pressed. • Daisy Wheel printer - A printer that uses a wheel with all the characters on it to produce output. The wheel spins to the desired characterand makes an imprint, then spins to go to the next character. It sounds like a little machine gun. • These printersgenerally aren't used much anymore due to the decreased cost of other printers that can produce graphics as well as text. The one good thing about a daisy-wheel printer is that the text is generally very crisp, but even that advantage is nullified now with laser printers that can produce very crisp characters as well. Advantages -Best print quality of impact printers Disadvantages -Very slow -Only one font can be used at a time because you must change out the Daisy Wheel to change fonts. -Cannot print graphics 3. Chain and band printers - Uses characters on a band or chain that is moved into place before striking the characters onto the paper. Advantages Very fast Disadvantages -Very loud -Very expensive You have been delegated the task of selecting a new printer from a range of different options currently on the market. The machine has to serve a small network of microcomputers in your office. Software used includes a word processing package, database, spreadsheet, and presentation packages. Assuming that cost is not a major constraint, list 10 features of the printers, which you would investigate in your evaluation. 1. Print quality, for example the print from dot matrix printers varies with the number of pins and even the best are inferior to laser printers. 2. Character formation, whether made from dots as in matrix printer, or full characters as with daisywheel or laser printer 3. Multi-part, i.e. whether several copies can be printed at once, as with an impact printer. 4. Fonts or type style; early computer users were satisfied with any quality whatsoever, but the advances into areas such as word processing and desk top publishing have stimulated a demand for varying type faces or fonts within the same document
  • 25. COMPUTER OPERATIONS PACKAGES 5. Letter quality, whether the quality is equivalent or superior to that of a good typewriter and so acceptable for the word processing of mail. Some printers have a choice of two print modes, draft quality and letter quality. 6. Speed, in terms of characters per second. 7. Graphics capabilities. 8. Flexibility, for example is it suitable for one task only, such as good letter quality but not graphics, as with daisywheel printers, or good graphics but slow speed and indifferent letter quality, as with some dot matrix printers. 9. Sheet feeding, in terms of single sheets, friction feed or sprocket feed. 10. Capital cost or what it costs to buy. 11. Running cost or what it costs in ribbons, print toner, special stationery maintenance. 12. Compatibility with standard packages; many programs support a range of printers by generating the correct control characters for fonts, features like italics and underline, and for graphics. 13. Robustness; some very cheap printers are ideal at home but would not last very long in an rmmakaha@gmail.com 24 office. 14. Reputation of the manufacturer as a supplier of printers. STORAGE DEVICES These are devices that store information permanently. They are also known as Auxiliary storage devices or Secondary storage devices. They include:- a) THE HARD DISK A fixed device for storing information within the computer system unit. The disk is not moveable and is also referred to as the C: drive. The amount of disk space a computer has determines the power of a computer. It provides fast access known as Random access and has high-speed storage. b) FLOPPY DISKETTE An external form of storage used for back up. Information can be deleted and rewritten and re-saved. The storage device is common for microcomputers. The disks are either High density or double density disks because data is stored more densely/ compactly than on regular density disks. Common size of disk is 31/2inches. ADVANTAGES OF FLOPPY DISKETTES 1. They are cheaper than Hard disks and CD-ROMS 2. They are portable hence used to transfer data or information from one computer to another 3. They offer direct access and they are faster than magnetic tapes DISADVANTAGES OF FLOPPY DISKETTES 1. They are prone to viruses 2. They are difficult to handle 3. They can easily be corrupted 4. They have a relatively short life span 5. They hold relatively small amounts of data 6. They are not always 100% reliable CARE AND HANDLING OF A FLOPPY DISKETTE 1. Don’t put the diskette near any magnetic field. 2. Don’t put the diskette near any electronic motor. 3. Don’t expose the diskette to direct sunshine or heat. 4. Store the diskette in a cool dry dust-free environment. 5. Don’t spill liquid onto the diskette. 6. Don’t use any diskette which has had liquids spilled on it. 7. Don’t bend or fold a diskette. 8. Don’t staple labels onto the diskette.
  • 26. COMPUTER OPERATIONS PACKAGES 9. Use a soft pencil or felt-tip pen when writing on diskette labels, as the pressure of a ballpoint may leave indentations on the magnetic surface. 10. Don’t touch the magnetic surface (the black plastic like plate) of the disk, as your fingerprints may hinder the drive in reading from and writing to the disk . rmmakaha@gmail.com 25 c) CATRIDGE TAPE Data is recorded in the form of magnetized spots on an iron oxide coating of a plastic tape. Gaps are used to separate individual data records. The tape is similar to audiotapes. Access of information from the tape is in sequential form and thus slow. d) CD-ROM (Compact Disk Read Only Memory) Beams of laser light are used to write on optical disks by magnetic means. After writing, the disk can only be read from and not written to. Access to information is direct and very fast. e) WORM (Write Once, Read Many) WORM Disks allow microcomputers with the proper drive known as a CD Rewriters (or a burner) to record own data on a blank CD. Once the recording is done, the disk can only be read from and cannot be rewritten. Erasable optical disks are also available and are known as EPROM. The major advantage of optical disks is their storage capacity. The information on one optical requires multiple floppies. f) DVD (Digital Versatile Disks) A form of optical disks similar to CD ROMS but has much more storage capacities of up to 3.9GB. They support audio and video as well as data on the same disk. g) ZIP DISKS These are high capacity removable diskettes. They have gained favor for back-up purposes. Some zip disks use magnetic technology and others use laser. They have a capacity of about 100MB. Storage devices differ in terms of capacity, cost and access methods. For any device to be used there is a need for the device drive on the computer e.g. A floppy disk drive. DISK CARE 1) Do not expose them to sun or a hot environment. 2) Keep them away from moisture or water. 3) Keep them away from magnetic fields i.e. Phones, tops of some monitors, magnetized items etc.. 4) Do not touch the actual tape. 5) Keep them away from dust. 6) Do not place heavy objects on them. 7) Write on a floppy disk label only with a felt-tip pen, or write before sticking the label 8) Avoid using rubber bands, paper clips and erasers on floppy disks HARDWARE CARE 1) Make sure there is enough space for the machines to breathe. (Fresh air is necessary to make the fan keep the electronics cool). 2) Do not block air vents with books. 3) Keep the computer dry. 4) House the machine in a dust free environment e.g. 1ST floor carpeted-room (Carpets suck dust) and, use a vacuum cleaner to clean the carpet. (Dust is the biggest killer of hard drives). 5) Do not expose the machine to extreme temperatures. 6) Properly shut down the machine before turn-off. 7) Pull the plug out of socket when there is thunder and lightning.
  • 27. COMPUTER OPERATIONS PACKAGES 8) Do not move the system when the computer is on. The hard drive can be damaged. 9) Use of UPS- Uninterruptible Power Supply in case of power failures, 10) Use of Surge Protectors against too high voltages. DEFINE HARDWARE GIVE EXAMPLES. Hardware comprises all of the physical parts of a computer, as distinguished from the data it contains or operates on, and the software that provides instructions for the hardware to accomplish tasks. DEFINE SOFTWARE GIVE EXAMPLES. Computer software (or simply software) refers to one or more computer programs and data held in the storage of a computer for some purpose. Program software performs the function of the program it implements, either by directly providing instructions to the computer hardware or by serving as input to another piece of software. rmmakaha@gmail.com 26 CLASSIFICATION OF COMPUTERS Computers differ based on their data processing abilities. They are classified according to purpose, data handling and functionality. • According to purpose, computers are either general purpose or specific purpose. General purpose computers are designed to perform a range of tasks. They have the ability to store numerous programs, but lack in speed and efficiency. Specific purpose computers are designed to handle a specific problem or to perform a specific task. A set of instructions is built into the machine. • According to data handling, computers are analog, digital or hybrid. ANALOG COMPUTERSwork on the principle of measuring, in which the measurements obtained are translated into data. Modern analog computers usually employ electrical parameters, such as voltages, resistances or currents, to represent the quantities being manipulated. Such computers do not deal directly with the numbers. They measure continuous physical magnitudes. DIGITAL COMPUTERSare those that operate with information, numerical or otherwise, represented in a digital form. Such computers process data into a digital value (in 0s and 1s). They give the results with more accuracy and at a faster rate. Hybrid computers incorporate the measuring feature of an analog computer and counting feature of a digital computer. For computational purposes, these computers use analog components and for storage, digital memories are used. • According to functionality, computers are classified as : Analog Computer An analog computeris a form of computer that uses continuous physical phenomena such as electrical, mechanical, or hydraulic quantities to model the problem being solved Digital Computer A computer that performs calculations and logical operations with quantities represented as digits, usually in the binary number system
  • 28. COMPUTER OPERATIONS PACKAGES Hybrid Computer (Analog + Digital) A combination of computers those are capable of inputting and outputting in both digital and analog signals. A hybrid computer system setup offers a cost effective method of performing complex simulations. rmmakaha@gmail.com 27 Classification on the basis of Size Major classes or categories of computers Supercomputers Describes a category of extremely powerful computers specifically designed for high-speed numeric computation. The computers can process hundreds of millions of instructions per second. High capacity computers capable of executing instructions faster than main frame are extremely expensive. The speed of executing these instructions generates extreme heat, and therefore the computers require special cooling system to operate. Uses include weather forecasting, scientific and mathematical research, and design of high-speed aircraft and space exploration. Mainframes Are large, powerful computers that are physically larger than micros and minis and usually have one or more central processors with faster instruction processing speeds? They typically process hundreds of millions of instructions per second. Mainframes have large primary storage capacities. Many mainframe models have the ability to service hundreds of users at once. Some commercial organizations require large amounts of data to be processed in the list possible time. Mainframes allow one to perform such functions Uses of mainframes include: data warehousing, commercial airline ticketing reservations, government record keeping financial servicing Application categories: Host computers, Database servers, and Transaction processors. Minicomputers Are larger and more powerful than most microcomputers but are smaller and less powerful than most mainframe computer systems. Serve in industrial process-control manufacturing plant computers and play a major role in CAM. Also take the form of powerful technical workstations for CAD applications. Often used as front-end processors/computers to help mainframe computers control data communications networks with large numbers of data entry terminals. Also used as powerful Network servers to help manage large interconnected LANs that tie together many workstations Downsizing is a term that was commonly used in the early nineties when smaller computers, capable of much of the functions of mainframes, began capturing the computer market. Minicomputers are suitable for mid-sized companies that require the computing power of mainframes to be efficient and at the same time be cost effective. Users of mini-computers would be smaller banks financial institutions, supermarket chains and departmental stores. Application categories: Network servers, and Application systems Microcomputers We refer to a microcomputer as a personal computer or PC. Microcomputers categorized by size include: Desktops, Laptops for example. Most microcomputers are single user computers. The late nineties have seen a huge influx of microcomputers whose sole aim was to provide affordable computing power to the general public.
  • 29. COMPUTER OPERATIONS PACKAGES They are now used as Network servers. The demand for microcomputers and the changes in microchip technology have produced cheaper computers that are affordable to students and the general public. Can support CAD. Users of microcomputers range from students, who use them for word processing, to a salesperson. Who depend on the microcomputer for information? Application categories: PCs, Network servers. Network servers are powerful microcomputers that controls coordinates communication resource sharing in LANs of interconnected PCs other devices. The main differences among the above computer types are in: • Processing speed, • Memory capacity • Number and capabilities or peripheral devices that can be attached to the computer • Usage. rmmakaha@gmail.com 28 COMPUTER APPLICATIONS a) Business- for administration, payroll and accounting. b) Government- keeping database records. c) Education- Record keeping, accounting and training in the classroom. d) Health- Record keeping, life-support systems. e) Sport- fitness monitoring. f) Art and Design- desktop Publishing, technical graphics, Computer Aided Design. g) Homes- PCs for home accounts, games, e-mail, online shopping, home education etc. h) Banks- Record keeping and updating, on-line Automated Teller Machines (ATMs). i) Supermarkets- Electronic point Of Sale Machines (EPOS) – tills. FACTORS TO CONSIDER WHEN YOU WANT TO PURCHASE OR BUYA COMPUTER 1. COST; how much can I afford to pay for a computer? Prices of personal computers range from a few hundred to thousands of dollars. Faster and more feature-rich PCs are usually more expensive. 2. AREA OF USE; where will my new PC be used? If you will be using it only in your home or office, a desktop computer will be suitable. However, if you will need to take it with you, you should consider purchasing a laptop (notebook) computer. 3. APPLICATIONS PACKAGES; Which application packages will I run on my computer? Make a list of applications for which you plan to use your PC. For example, will you use your PC to prepare letters and reports? Analyze numeric and financial data? Prepare visual presentations? Access the Internet? Listen to music? Create and work with graphics? 4. DURATION; How long will I keep this computer?Try to estimate the length of time (years) you will use your computerbefore BUYING the next one. If you expect use your PC for several years or if you think you may later want to add new applications, CONSIDER one that is expandable, so you can add new components, such as a modem, printer, or add-on boards. Make sure the PC has expansion slots so you can connect these devices to your PC. 5. MANUFACTURER AND SELLER REPUTATION. Check out the manufacturers and seller’s reputations.Talk with friends, co-workers, classmates, teachers, and others about their PCs. Ask about the performance of their PCs and get recommendations from persons you trust. Eventually you may need to have your PC serviced. Ideally, the vendor has a service department that can repair your PC. If not, you may need to locate a third-party to provide this service. Reputable computer manufactures include:
  • 30. COMPUTER OPERATIONS PACKAGES 1. Hewlett-Packard 2. Apple 3. Sun Microsystems 4. Dell 5. Panasonic 6.Sony 7.Toshiba 8. Shuttle 9. IBM 10. Samsung Electronics 11. Hitachi 12. Fujitsu Siemens rmmakaha@gmail.com 29 6. WARRANTIES GUARANTEES 7. PC ARCHITECTURE. PC architecture refers to the design and construction of the PC and its system unit, and not all architectures are the same. For example, the architecture of an Apple Macintosh differs from that of an IBM or compatible PC. Therefore, software written for an Apple Macintosh PC may not run on an IBM or IBM-compatible PC. Although some users prefer a Macintosh PC, more software is available for IBM and IBM-compatible PCs. 8. MICROPROCESSOR SPEED. Selecting the right microprocessor is extremely important. Processing speed, measured in megahertz (MHz) or gigahertz (GHz), is probably the first consideration. The higher the number of MHz or GHz, the faster the processor will manipulate data. If speed is important, consider choosing a microprocessor with a speed of 2 GHz or more. PCs containing microprocessors with speeds up to 10 GHz and higher are available. 9. MAIN MEMORY (RAM). Main memory (RAM) is needed for the temporary storage of programs and data while the data is being processed. Some application software requires a considerable amount of RAM to function properly, and newer software versions usually require more RAM than older versions. Typical PCs now come with 2 gigabytes (GB), 5GB, or more of RAM. Make certain the PC has sufficient RAM to run the software you will be using. 10. SECONDARY STORAGE (ROM). What type(s) and amounts of secondary storage are you likely to need? Typical computers come with a floppy disk drive, cd drive, USB port/ drive and a hard disk drive already installed. A hard disk drive contains one or more rigid storage platters and provides for the permanent storage of considerably more data. However, the disk itself cannot be removed from the drive. The STORAGE CAPACITY of a hard disk is an important consideration because it is used to store all system and application software. Typical hard disk capacities are 100, 200, 500GB or 2TB and more. Be certain the PC you are considering has sufficient secondary capacity for your needs CD-ROM or DVD drives provide high storage capacities. Most software publishers store their programs on CD-ROM or DVDs because of the high capacity and because DVD/CD-ROMs operate faster than floppy disks. If you will use your PC to play movies, your purchase should include a DVD (digital video disk) drive. If you will work with large files, consider purchasing a computer that includes a DVD/CD-RW drive. A DVD/CD-RW disk is a reusable high-capacity disk that allows you to store huge amounts of data and to erase data no longer needed. 11. PORTS.The number of ports (slots) available inside the system unit determines the number of add-on boards that can be installed inside the system unit. For example, you cannot connect a printer to your computer unless youcomputerr is equipped with an appropriate port (slot). Be sure the PC contains the necessary slots for the add-on boards and peripheral devices you will be using with your computer. 12. INPUT DEVICES.Typical input devices are a keyboard and a mouse, although other kinds of input devices are available. Most keyboards and mice operate similarly. However, there are slight differences in how each feels to the user. Before buying a PC, you may want to test the keyboard and mouse for comfort and ease of use. Some sellers will allow you to exchange the keyboard or mouse that comes with the computerfor a different one.
  • 31. COMPUTER OPERATIONS PACKAGES 13. OUTPUT DEVICES. Output devices produce output in either soft copy or hard copy form. Most PCs come with a monitor (for soft copy output), but you may have to purchase a hard copy device, such as a printer, separately. 14. MONITORS. There are wide differences among PC monitors, with resolution being perhaps the most important variable. Resolution refers to the clarity of the text and images being displayed. Before making a purchase, carefully evaluate the monitor’s resolution. Many vendors allow you to choose from monitors with varying resolutions. A resolution of 1,024 by 1,024 is considered high-resolution, in which text and images display exceptionally clearly. High-resolution monitors are typically more expensive. Monitor size is another important consideration. Viewing areas range from 15 diagonal inches to 21 inches and higher. Larger monitors are usually more expensive, but may be worth the extra cost. For example, an individual with weak vision may prefer a larger monitor. If your desktop space is limited, consider purchasing a flat-panel monitor, which occupies less space. Flat-panels are more expensive than standard monitors, however. NECESSARY CONDITIONS FOR AN IDEAL COMPUTER ROOM ENVIRONMENT. 1. Cleanliness [books, manuals not encouraged] because they bring dust caught fire rmmakaha@gmail.com 30 easily. 2. Air conditioners, which control the room and dehumidates it. 3. It should be dust free; dust is the biggest “killer” of hard drives. 4. No carpets, they caught fire more easily. 5. You are not allowed to eat, smoke or drink in the computer room. 6. No magnetic material should be in the computer room. 7. The computer room should be located in such a way that computers are not exposed to direct sunlight or hot environments, use curtains if otherwise. 8. The computer room should be fitted with burglar bars, alarm systems, or guarded 24hours to ensure security. 9. The computer room should have surge protectors or suppressors to guard against electrical faults and high voltages. 10. The computer room should have UPS [uninterrupted power supply] in case of power failures, which may be fatal. 11. Computer room should be well ventilated, to allow for air circulation, 12. Foreign media, such as floppy diskettes, flash disks should not be allowed in order to minimize virus spread. 13. Always switch off machines if not in use. 14. Avoid overloading circuits. 15. All cabling and wiring should not be exposed; it should be covered and should not criss cross the room. 16. Leave enough space between computers and the walls. 17. Do not use chalk the computer room , dry wipe markers are encouraged.
  • 32. COMPUTER OPERATIONS PACKAGES DUTIES RESPONSIBILITIES OF COMPUTER PERSONNEL ROLES OF A Database Administrator (DBA) a) The design of the database b) After the initial design, the DBA must monitor the performance of the database, and if problems surface (such as a particular report taking an unacceptably long time to produce), appropriate changes must be made to the database structure. c) Keeping users informed of changes in the database structure that will affect them; for example, if the size or format of a particular field is altered or additional fields added d) Maintenance of the data dictionary for the database, and responsibility for establishing conventions for naming tables, columns, indexes 7 so on. e) Implementing access privileges for all users of the database; that is, specifying which items can be accessed and / or changed by each user. f) Allocating passwords to each user. g) Providing training to users in how to access and use the database. h) Manage the organization of i. -data resources ii. -database plans iii. -design iv. -operations v. -training vi. -user support vii. -security Maintenance i) Maintain data consistency and security j) Approve access to data stored k) Approve access procedures l) ABILITY to delete, add, modify –existing data must be tightly controlled. 1. COMPUTER SUPPORT SPECIALISTSprovide technical assistance, support, and advice to customers and other users. This occupational group includes technical support specialists and help-desk technicians. These troubleshooters interpret problems and provide technical support for hardware, software, and SYSTEMS. They answer telephone calls, analyze problems by using automated diagnostic programs, and resolve recurring difficulties. Support specialists may work either within a company that uses computer SYSTEMSor directly for a computer hardware or software vendor. Increasingly, these specialists work for help-desk or support services firms, for which they provide computer support to clients on a contract basis. 2. TECHNICAL SUPPORT SPECIALISTSanswer telephone calls from their organizations’ computer users and may run automatic diagnostics programs to resolve problems. Working on monitors, keyboards, printers, and mice, they install, modify, clean, and repair computer hardware and software. They also may write training manuals and train computer users in how to use new computer hardware and software. In addition, technical support specialists oversee the daily performance of their company’s computer SYSTEMSand evaluate software programs with regard to their usefulness. 3. HELP-DESK TECHNICIANSassist computer users with the inevitable hardware and software questions that are not addressed in a product’s instruction manual. Help-desk technicians field telephone calls and e-mail messages from customers who are seeking guidance on technical problems. In responding to these requests for guidance, help-desk technicians must listen carefully to the customer, ask questions to diagnose the nature of the problem, and then patiently walk the customer through the problem-solving steps.Help-desk technicians deal directly with customer issues, and companies value them as a source of feedback on their products. These rmmakaha@gmail.com 31
  • 33. COMPUTER OPERATIONS PACKAGES technicians are consulted for information about what gives customers the most trouble, as well as other customer concerns. Most computer support specialists start out at the help desk. 4. NETWORKADMINISTRATORS AND COMPUTERSYSTEMS ADMINISTRATORSdesign, install, and support an organization’s local-area network (LAN), wide-area network (WAN), network segment, Internet, or intranet system. They provide day-to-day onsite administrative support for software users in a variety of work environments, including professional offices, small businesses, government, and large corporations. They maintain network hardware and software, analyze problems, and monitor the network to ensure its availability to system users. These workers gather data to identify customer needs and then use the information to identify, interpret, and evaluate system and network requirements. Administrators also may plan, coordinate, and implement network security measures. 5. SYSTEMSADMINISTRATORSare the information technology employees responsible for the efficient use of networks by organizations. They ensure that the design of an organization’s computer site allows all of the components, including computers, the network, and software, to fit together and work properly. Furthermore, they monitor and adjust the performance of existing networks and continually survey the current computer site to determine future network needs. Administrators also troubleshoot problems reported by users and by automated network monitoring SYSTEMSand make recommendations for enhancements in the implementation of future servers and networks. 6. In some organizations, COMPUTER SECURITY SPECIALISTSmay plan, coordinate, and implement the organization’s information security. These workers may be called upon to educate users about computer security, install security software, monitor the network for security breaches, respond to cyber attacks, and, in some cases, gather data and evidence to be used in prosecuting cyber crime. The responsibilities of computer security specialists has increased in recent years as there has been a large increase in the number of cyber attacks on data and networks. This and other growing specialty occupations reflect an increasing emphasis on client-server applications, the expansion of Internet and intranet applications, and the demand for more end-user support. 7. COMPUTER PROGRAMMERSwrite, test, and maintain the detailed instructions, called programs that computers must follow to perform their functions. Programmers also conceive, design, and test logical structures for solving problems by COMPUTER. Programmers write programs according to the specifications determined primarily by COMPUTER software engineers and systems analysts.After the design process is complete, it is the job of the Programmer to convert that design into a logical series of instructions that the COMPUTER can follow. The Programmer codesthese instructions in a conventional programming language such as COBOL; an artificial intelligence language such as Prolog; or one of the most advanced object-oriented languages, such as Java, C++, or ACTOR. Different programming languages are used depending on the purpose of the program. 8. DATA PREPARATION STAFF Are those people responsible for the translation of data into machine readable form. 9. COMPUTER SCIENTISTSwork as theorists, researchers, or inventors. Their jobs are distinguished by the higher level of theoretical expertise and innovation they apply to complex problems and the creation or application of new technology. Those employed by academic institutions work in areas ranging from complexity theory to rmmakaha@gmail.com 32
  • 34. COMPUTER OPERATIONS PACKAGES hardware to programming-language design. Some work on multidisciplinary projects, such as developing and advancing uses of virtual reality, extending human-computer interaction, or designing robots. Their counterparts in private industry work in areas such as applying theory; developing specialized languages or information technologies; or designing programming tools, knowledge-based systems, or even computer games. 10. DATA ENTRY AND INFORMATIONPROCESSING WORKERShelp ensure the smooth and efficient handling of information. By keying in text, entering data into a computer, operating a variety of office machines, and performing other clerical duties, these workers help organizations keep up with the rapid changes that are characteristic of today’s “Information Age.” In addition to the job titles discussed below—such as word processors, typists, and data entry keyers—data entry and information processing workers are known by various other titles, including electronic data processors, keypunch technicians, and transcribers. 11. DATA ENTRY KEYERSusually input lists of items, numbers, or other data into computers or complete forms that appear on a computer screen. They also may manipulate existing data, edit current information, or proofread new entries into a database for accuracy. Some examples ofdata sources include customers’ personal information, medical records, and membership lists. Usually, this information is used internally by a company and may be reformatted before other departments or customers utilize it. 12. DATA CONTROL is our customer services area for all agencies that utilize Information Technology's services for reports of any kind. This section receives and distributes all incoming data for appropriate processing; they set up batch reporting for all agencies and submit schedules for processing to Computer Operations. After processing has occurred, they check and distribute reports to all customers. This area interacts with agency customers and other Information Technology areas to resolve processing problems. This area maintains all tape media including updating the tape inventory system and it also has responsibility for off site tape storage. Updating the Information Technology web page using HTML and other software tools is done by Data control. Data control is also responsible for all data preparation prior to centralized processing. Assisting the paper peripheral area and reception area are also functions of this section. 13. COMPUTER OPERATORSare responsible for the operation of all enterprise, Unix, NT, and Windows 2000 servers, Unix and personal computers that are utilized to service the County's customer base. This area receives all hardware service calls, assists in terminal and communication equipment installation and software/hardware trouble diagnosis. Processing of all batch production work as well as all paper peripheral processing are also functions of Computer Operations. 14. NETWOR MANAGER, managing a network infrastructure and providing technical support and advice to the client organisations. This type of post would usually require the postholder to be educated to degree level or equivalent standard and to have considerable experience of network management and protocols including TCP/IP. Additional requirements might include experience in the management of industry standard network operating systems such as Novell NetWare, UNIX and MS Windows NT 2000 server, together with skills in the use of database applications, such as Oracle, email server applications such as MS Exchange 5.5 or 2000 and PC applications such as MS Office XP. Research – important area 1. FIND OUT THE DUTIES AND RESPONSIBILITIES OF THE FOLLOWING rmmakaha@gmail.com 33 a) Computer programmer b) System analyst c) System administrator d) Computer librarian
  • 35. COMPUTER OPERATIONS PACKAGES rmmakaha@gmail.com 34 e) Data preparation staff f) Network administrator g) Data control staff h) IT manager i) Data processing manager j) Computer operators k) Data capturing clerk 2. Write notes on DATA PROCESSING METHODS a) Manual data processing b) Mechanical data processing c) Electronic data processing d) Automatic data processing e) Online data processing f) Distributed data processing g) Centralized data processing h) Transaction processing i) Decentralized data processing j) Time sharing data processing k) Batch or offline data processing 3. Advantages and disadvantages of computers Ask if you are not sure DATA SECURITY /PROTECTION Data Security/Protection Refers to keeping data safe from various hazards or dangers like natural hazards, deliberate corruption or destruction of software hardware by malicious or terrorist acts, illegal access to data by hackers [people who break into the system] accidental destruction of data by hardware or software failure [operator error]. MEASURES TO ENSURE DATA SECURITY 1. Data Encryption/Decryption- Data is coded before transmission over a WAN decrypted only if you have the key code to decrypt the data on the receiving end. The process of transforming a message in ordinary language i.e. plain text to produce what is called cipher text which is then send along a communication line/link. The receiving computer uses another transformation to decode the message. a. Definitions of decryption on the Web: • The process of converting encrypted content back into its original form, often the process of converting cipher text to plaintext. Decryption is the opposite of encryption. • Definitions of encryption on the Web: • Any procedure used in cryptography to convert plaintext into cipher text in order to prevent anyone except the intended recipient from reading that data. There are many types of data encryption, and they are the basis of network security. Common types include Data Encryption Standard and public-key encryption. • Definitions of cipher text on the Web: • Data that has been transformed by encryption so that its semantic information content (ie, its meaning) is no longer intelligible or directly available. 2. Firewall- a firewall is a software program designed to prevent unauthorized access to a PC or network through a connection to the Internet. It works by monitoring all data sent to and from the PC and comparing the data with a set of user-defined security criteria. Any data that does not meet that criteria is blocked. Firewalls also process encrypted data. They verify the validity of the user. User would require access to the firewall before they can transmit data. Latest firewalls also have the ability to detect virus software in packets of data that is sent through the network. Firewalls disallow data transmission if it detects strains of virus on the data being transmitted. 3. Usernames Passwords-Passwords restrict only authorized personnel/users to have access to the data or computer rooms [cards]. Passwords bring in an aspect of accountability, if a file is deleted, the person with the password will be reported as the culprit through logging. Passwords can be forgotten. Widely used by companies to protect their equipment data 4. Authorized entry to computer installations-Most installations have card readers, voice recognition systems or keypads on the doors that prohibit entry to unauthorized personnel. 5. Backing-up files on external disks periodically. 6. Keeping backup copies of files in a different location and making about 3 generations of backup.
  • 36. COMPUTER OPERATIONS PACKAGES 7. Saving work frequently 8. Avoiding viruses. 9. Restricting access to the computer room. Access could be only through codes, voice recognition etc. 10. Installing fire alarms. 11. Lining computer rooms with fire resistant material. 12. Placing the computer room in upper floors of a building to avoid burglaries. 13. Having a security guard 24 hours a day. Summary - Keeping data secure Measures that can be taken to keep data safe include: • Making regular back-ups of files. (Back up copies should be stored safely in fireproof safes rmmakaha@gmail.com 35 or in another building.) • Protecting yourself against viruses by running anti-virus software. • Using a system of passwords so that access to data is restricted. • Safe storage of important files stored on removable disks - eg locked away in a fireproof and waterproof safe. • Allowing only authorized staff into certain computer areas, eg by controlling entry to these areas by means of ID cards or magnetic swipe cards. • Always logging off or turning terminals off and if possible locking them. • Avoiding accidentally deletion of files by write-protecting disks. • Using data encryption techniques to code data so that it makes no apparent sense BACK UP Copying or saving data to a different location. One can restore the backup copy if data is lost or damaged. To create a copy of a disk’s contents on another location for safe keeping. Since hard drives are not infallible, it is recommended that you backup its contents regularly. DISASTER PLANNING Many companies have comprehensive emergency plans so that even after suffering a severe: Bomb Fire damage Natural disaster, the company can be up and running within a day or two. A disaster recovery service/programme provides for example Office space Computer facilities Phones Desks, at an emergency BACKUP site. A completely up to date copy of the company Database may be permanently maintained at this site with all transactions being transmitted to this remote site updating the database, copying etc. The data should be backed up/stored to one or more media to ensure recovery in case of disaster. The back up procedures and media should be tested periodically to assess their effectiveness. Definitions of disaster plan on the Web: • The documented policies and procedures intended to either prevent damage, minimize damage, or recover from damage to record materials. Definitions of disaster recovery plan on the Web: • The document that defines the resources, actions, tasks and data required to manage the business recovery process in the event of a business interruption. The plan is designed to assist in restoring the business process within the stated disaster recovery goals. • Part of an overall contingency plan. The plan for a process whereby an enterprise would restore any loss of data in the event of fire, vandalism, natural disaster, or system failure.
  • 37. COMPUTER OPERATIONS PACKAGES MAJOR THREATS TO INFORMATION SYSTEMS/COMPUTERS Key threats to data security • Data can be lost or damaged during a system crash - especially one affecting the hard rmmakaha@gmail.com 36 disk. • Data can become corrupt as a result of faulty disks or disk drives, or power failures. • Data can be lost by accidentally deleting or overwriting files. • Data can be lost or become corrupted by computer viruses. • Data can be hacked into by unauthorized users and deleted or altered. • Data can be destroyed by terrorist activities, war, bombs and fire. • Data can be deleted or altered by unpleasant employees wishing to make money or seek revenge on their employers. Explain 5 major threats to information systems; for each threat describe its impact and preventative measure you would adopt to prevent it. [15]. THREAT IMPACT CONTROL Hardware failure • You are grounded • You cannot access the system • Data is incorrectly/ incompletely processed • Have spares in the warehouse. • Do regular servicing • Have a disaster plan • Run hardware diagnostics frequently Electrical faults • Loss of data • Disk crushes • Damage to hardware • Have standby generators • Install UPS [uninterrupted power supply] • Install Surge suppressors/ protectors Software failures • Operations are grounded • Buy software from reputable vendors. • Do regular back ups • Software diagnostics Natural disasters/ physical threats • Absolute destruction • Relocate backups to other areas free from disasters Viruses • Deletion corruption of files • Reformatting of documents • System may fail to work • Install a reliable anti-virus software • Never download unknown e-mail attachments • Scan unknown diskettes Hackers, Computer crime • Security is breached • Security is bypassed • Destruction of files • Data is stolen • Change passwords regularly • Employ a security guard • Install a firewall • Prevent unauthorized access to computer facilities. War and Terrorist activity Human error
  • 38. COMPUTER OPERATIONS PACKAGES Definitions of computer abuse on the Web: • The willful or negligent unauthorized activity that affects the availability, confidentiality, or integrity of computer resources. Computer abuse includes fraud, embezzlement, theft, malicious damage, unauthorized use, denial of service, and misappropriation Definitions of hacking on the Web: • Unauthorized use, or attempts to circumvent or bypass the security mechanisms of an information system or network. Hacking means illegally accessing other people's computer systems for destroying, disrupting or carrying out illegal activities on the network or computer systems. DATA INTEGRITY/RELIABILITY • Refers to the correctness AND The accuracy of data after being transmitted or processed • Data in the computer system may become incorrect, corrupted or of poor quality in many different ways at any stage during data processing. Consequences of system failure: Loss of business due downtime Delays Air traffic control system could well have catastrophic results rmmakaha@gmail.com 37 COMPUTER CRIME/FRAUD Computer crimes are criminal activities, which involve the use of information technology to gain an illegal or an unauthorized access to a computer system with intent of damaging, deleting or altering computer data. Computer crimes also include the activities such as electronic frauds, misuse of devices, identity theft and data as well as system interference. Computer crimes may not necessarily involve damage to physical property. They rather include the manipulation of confidential data and critical information. Computer crimes involve activities of software theft, wherein the privacy of the users is hampered. These criminal activities involve the breach of human and information privacy, as also the theft and illegal alteration of system critical information. The different types of computer crimes have necessitated the introduction and use of newer and more effective security measures. Computer Fraud/Crime Criminal actions accomplished through the use of computer systems, especially with the intent to defraud, destroy, damage, or make unauthorized use of computer resources. E.g. improper transfer of funds from one account to another TYPES OF COMPUTER CRIME/FRAUD a) Intellectual Crime – cracking into a computer system for the purpose of transferring or obtaining funds is a typical e.g. b) Destruction of property – destroying a computer property c) Theft – Software piracy which is unauthorized copying of software. Hardware software being taken away without the knowledge/consent of its owners. d) Fraud achieved by the manipulation of computer records. e) * Spamming wherever outlawed completely or where regulations controlling it are violated. f) * Deliberate circumvention of computersecurity systems. g) * Unauthorized access to or modification of programs (see software cracking and hacking) data. h) * Intellectual property theft, including software piracy. i) * Industrial espionage by means of access to or theft of computer materials. j) * Identity theft where this is accomplished by use of fraudulent computer transactions. k) * Writing or spreading computerviruses or worms.
  • 39. COMPUTER OPERATIONS PACKAGES l) * Salami slicing is the practice of stealing money repeatedly in extremely small rmmakaha@gmail.com 38 quantities. m) *DNSDenial-of-service attack, where company websites are flooded with service requests and their website is overloaded and either slowed or crashes completely. n) * Making and digitally distributing child pornography Types of Computer Crime Hacking: The activity of breaking into a computer system to gain an unauthorized access is known as hacking. The act of defeating the security capabilities of a computer system in order to obtain an illegal access to the information stored on the computer system is called hacking. The unauthorized revelation of passwords with intent to gain an unauthorized access to the private communication of an organization of a user is one of the widely known computer crimes. Another highly dangerous computer crime is the hacking of IP addresses in order to transact with a false identity, thus remaining anonymous while carrying out the criminal activities. Phishing: Phishing is the act of attempting to acquire sensitive information like usernames, passwords and credit card details by disguising as a trustworthy source. Phishing is carried out through emails or by luring the users to enter personal information through fake websites. Criminals often use websites that have a look and feel of some popular website, which makes the users feel safe to enter their details there. Computer Viruses: Computer viruses are computer programs that can replicate themselves and harm the computer systems on a network without the knowledge of the system users. Viruses spread to other computers through network file system, through the network, Internet or by the means of removable devices like USB drives and CDs. Computer viruses are after all, forms of malicious codes written with an aim to harm a computer system and destroy information. Writing computer viruses is a criminal activity as virus infections can crash computer systems, thereby destroying great amounts of critical data. Cyberstalking: The use of communication technology, mainly the Internet, to torture other individuals is known as cyberstalking. False accusations, transmission of threats and damage to data and equipment fall under the class of cyberstalking activities. Cyberstalkers often target the users by means of chat rooms, online forums and social networking websites to gather user information and harass the users on the basis of the information gathered. Obscene emails, abusive phone calls and other such serious effects of cyberstalking have made it a type of computer crime. Identity Theft: This is one of the most serious frauds as it involves stealing money and obtaining other benefits through the use of a false identity. It is the act of pretending to be someone else by using someone else's identity as one's own. Financial identity theft involves the use of a false identity to obtain goods and services and a commercial identity theft is the using of someone else’s business name or credit card details for commercial purposes. Identity cloning is the use of another user's information to pose as a false user. Illegal migration, terrorism and blackmail are often made possible by means of identity theft. The different types of computer crimes involve an illegal exploitation of the computer and communication technology for criminal activities. While the advancing technology has served as a boon to mankind, the destructively directed human intellects are all set to turn technology into a curse. However, crimes are sure to end, as it is truth that always triumphs! 1. Intellectual crime – cracking into a computer system with the sole aim of transferring or stealing funds, e.g. Salami slicing which is the activity of obtaining or stealing money repeatedly in extremely small quantities over a period of time 2. Destruction of property 3. Software piracy
  • 40. COMPUTER OPERATIONS PACKAGES 4. Deliberate circumvention of computer security systems or unauthorized access to or modification of computer programs and data; i.e. hacking which attempts to bypass the security mechanism of a computer system or network 5. Theft of computer hardware and software or taking away software without the owner’s rmmakaha@gmail.com 39 consent 6. Making and distributing pornography MEASURES TO COUNTER OR COMBAT COMPUTER CRIME [COMPUTER SECURITY] Careful vetting of employees Separation of duties Use of passwords Security manager software-to monitor attempts to access the system whether successful or not. Educating staff Prevention of unauthorized access to the computer operations room Data Encryption/Decryption 1. Establish strong passwords Implementing strong passwords is the easiest thing you can do to strengthen your security. Cloutier shares his tip for crafting a hard-to-crack password: use a combination of capital and lower-case letters, numbers and symbols and make it 8 to 12 characters long. You should definitely avoid using: any personal data (such as your birthdate), common words spelled backwards and sequences of characters or numbers, or those that are close together on the keyboard. Use their convenient password checker to see how strong yours is. As for how often you should change your password, Cloutier says that the industry standard is every 90 days, but don't hesitate to do it more frequently if your data is highly-sensitive. Another key: make sure every individual has their own username and password for any login system, from desktops to your CMS. Never just use one shared password, says Cloutier. And finally, Never write it down! he adds. 2. Put up a strong firewall In order to have a properly protected network, firewalls are a must, Cloutier says. A firewall protects your network by controlling internet traffic coming into and flowing out of your business. They're pretty standard across the board -- Cloutier recommends any of the major brands. 3. Install antivirus protection Antivirus and anti-malware software are essentials in your arsenal of online security weapons, as well. They're the last line of defense should an unwanted attack get through to your network, Cloutier explains. 4. Update your programs regularly Making sure your computer is properly patched and updated is a necessary step towards being fully protected; there's little point in installing all this great software if you're not going to maintain it right. Your security applications are only as good as their most recent update, Watchinski explains. While applications are not 100 percent fool-proof, it is important to regularly update these tools to help keep your users safe.
  • 41. COMPUTER OPERATIONS PACKAGES Frequently updating your programs keeps you up-to-date on any recent issues or holes that programmers have fixed. rmmakaha@gmail.com 40 5. Secure your laptops Because of their portable nature, laptops are at a higher risk of being lost or stolen than average company desktops. It's important to take some extra steps to make certain your sensitive data is protected. Encryption software changes the way information looks on the harddrive so that, without the correct password, it can't be read. 6. Secure your mobile phones Cloutier points out that smartphones hold so much data these days that you should consider them almost as valuable as company computers -- and they're much more easily lost or stolen. As such, securing them is another must. The must-haves for mobile phones: • Encryption software • Password-protection (Cloutier also suggests enabling a specific lock-out period, wherein after a short amount of time not being used, the phone locks itself) • Remote wiping enabled 7. Backup regularly Scheduling regular backups to an external hard drive, or in the cloud, is a painless way to ensure that all your data is stored safely. The general rule of thumb for backups: servers should have a complete backup weekly, and incremental backups every night; personal computers should also be backed up completely every week, but you can do incremental backups every few days if you like (however long you could live without your data, Cloutier explains). Getting your data compromised is a painful experience -- having it all backed up so you don't completely lose it will make it much less so. 8. Be careful with e-mail, IM and surfing the Web It's not uncommon for a unsuspecting employee to click on a link or download an attachment that they believe is harmless -- only to discover they've been infected with a nasty virus, or worse. 9. Educate your employees Teaching your employees about safe online habits and proactive defense is crucial. Educating them about what they are doing and why it is dangerous is a more effective strategy than expecting your IT security staff to constantly react to end users’ bad decisions, Watchinski says. It's not easy: One of the most difficult things to do is protect end users against themselves, he adds. But ultimately, prevention is the best approach to handling your data security. Make sure your employees understand how important your company's data is, and all the measures they can take to protect it. 10. Data encryption Encryption scrambles data, and is used to protect information that is being held on a computer, stored on external media such as DVDs or transmitted over a network. 11. Intrusion detection These products monitor system and network activity to spot potential security breaches. If a detection system suspects an attack, it can generate an alarm, such as an email alert, based upon the type of activity it has identified. COMPUTER VIRUS What is it? An executable computer program written intentionally to alter the way a computer operates without permission, to do harm to the computer. Types of Computer Viruses • Macro Viruses – are programmed as macros and embedded into a file or document and when the document is opened the virus is activated. A macro is a list of commands or actions that are found under key names of headings. Macro viruses typically infect global
  • 42. COMPUTER OPERATIONS PACKAGES settings files such as Word templates so that subsequently edited documents are contaminated with the infective macros • Boot Sector Viruses – A virus which attaches itself to the first part of the hard disk that is read by the computer upon bootup. These are normally spread by floppy disks. They only affect the computer’s boot sector such that the next time you try to start the computer it fails to boot • Time Bomb – is designed to cause damage to a computer at a specified date and time, rmmakaha@gmail.com 41 e.g. Friday 13th, March 6th • Logic Bomb – checks for particular conditions or states of the system which when satisfied triggers the perpetration of an unauthorized and usually destructive act. It lies dormant for most of the time and is triggered by an event • Memory resident virus – resides in a computer’s volatile memory (RAM). • Polymorphic viruses – a virus that not only replicates itself by creating multiple files of itself, but it also its digital signature every time it replicates. This makes it difficult for less sophisticated antivirus software to detect • Program viruses e.g. cascade, pacman 1508, override. • Boot viruses e.g. pasta, pentagon, Michelangelo • Internet Viruses e.g. Trojan horse, Stealth DEFINITION2. A virus is acomputer program designed to enter yourcomputer and tamper with your files without your knowledge. Once the program containing the virus is open, the activated virus can not only infect other programs and documents on youcomputerr, it can duplicate and transmit itself to other computers that are connected to yours, just like a physical virus can move from one human host to another. Virusesbegan in the late 1980s as personal computers and electronic bulletin boards became more common. Back then, operating systems, word processing programs and other programs were stored on floppy disks. Hidden Viruseswere programmed onto these disks; as the disks were transferred from person to person, the virus spread. WHO CREATES VIRUSES? Where do Virusescome from? Every virus is created by an author with a different motive—but all virus builders feel their actions are justified. For some, a killer virus is the ultimate technical challenge, like climbing a mountain. For others, creating Viruses is a form of self-expression. Some disgruntled employees, consumers or citizens turn to virus building as revenge for perceived injustices. And though it’s a frightening thought, some Virusesare built and aimed by legitimate (but disreputable) businesses to weaken competitors. Other virus authors want to make their mark in Internet history; these writers get a thrill out of seeing their virus cause damage enough to attract news headlines both online and on the evening news. What Viruses Do? /Signs symptoms of an infected computer. Reduced memory or disk space Files are overwritten or damaged Hard drive may be erased Data is modified /corrupted. Change files date stamp Drive lights blink without reason Longer times are experienced when loading programs Slower system operation. • Deletion of data files • The computer completely fails to work • Erasure or deletion of executable files • Formatting of the hard disks • Filling up of disk space
  • 43. COMPUTER OPERATIONS PACKAGES • Programs suddenly take longer to load. • The size of a program changes. • The disk runs out of free space when it seems to have plenty. • The CHKDSK command does not show the correct amount of bytes available. • Bit errors frequently occur while running Windows. • The disk drive is active when it should not be. • The hard drive is inaccessible when booting from a floppy drive. • Unrecognized files appear. • File names change. • The keyboard makes a clicking noise. • The screen becomes distorted. • Text on screen does unusual things. • CMOS settings, AUTOEXEC.BAT, or CONFIG.SYS files change unexpectedly (Symantec). A large part of detection is anti-virus software. Like a doctor, anti-virus software often uses the above listed symptoms to identify and eradicate an infection. What are the symptoms of an infected computer? It’s not always easy to tell if your computer has been compromised. More than ever before, the authors of viruses, worms, Trojans and spyware are going to great lengths to hide their code and conceal what their programs are doing on an infected computer. That’s why it’s essential to follow the advice given in this guide: in particular, install Internet security software, make sure you apply security patches to your operating system and applications and backup your data regularly. It’s very difficult to provide a list of characteristic symptoms of a compromised computer because the same symptoms can also be caused by hardware and/or software problems. Here are just a few examples: • Your computer behaves strangely, i.e. in a way that you haven’t seen before. • You see unexpected messages or images. • You hear unexpected sounds, played at random. • Programs start unexpectedly. • Your personal firewall tells you that an application has tried to connect to the Internet (and it’s not a program that you ran). • Your friends tell you that they have received e-mail messages from your address and you haven’t sent them anything. • Your computer ‘freezes’ frequently, or programs start running slowly. • You get lots of system error messages. • The operating system will not load when you start your computer. • You notice that files or folders have been deleted or changed. • You notice hard disk access (shown by one of the small flashing lights) when you’re not aware of any programs running. • Your web browser behaves erratically, e.g. you can’t close a browser window. How computers are infected with Viruses? Use of infected floppy diskettes on uninfected computers. Floppy disks or other media that users can exchange. Downloading unknown files, when your computer is connected to the Internet. Opening an E-mail attachment. Email attachments. Accepting unknown program installations from the internet Use of network files/direct connection/through networks. Software piracy [buying software from unauthorized agents]. Pirated software. Booting a PC from an infected medium. Executing an infected program. Opening an infected file. rmmakaha@gmail.com 42
  • 44. COMPUTER OPERATIONS PACKAGES Shareware. Viruses may be sent by opening email attachments, clicking on spam, visiting corrupt websites and links online, • Opening spreadsheets or even the original method—infected disks. • But the Internet is now the superhighway for virus transmission. rmmakaha@gmail.com 43 Sharing of storage media • Through e-mail attachments • Networks – if your computer is connected to a home network or if your work computer is part of network, you may find yourself with an infection through no fault of your own. There isn’t much you can do to stop these kinds of infections, short of having your network administrator ensure that everyone’s antivirus software is up to date so that the invading bug can be removed as quickly as possible. • Internet downloads including software piracy • Rogue Websites. It is depressing to know that you may become infected with spyware or a virus by doing nothing more than simply visiting a website, but it is true. Many adult websites, gambling websites and other less than trustworthy websites will attempt to automatically access your computer when you visit them. They often install adware bugs that will cause a flurry of pop ups to appear on your screen. This adware will often allow for other programs with even more nefarious purposes to be installed and before you know it, your computer will be swamped. To stop these rogue websites, adjust the settings on your antivirus software and firewall so that no outside connections can be made and no programs can be installed without your express permission. CHARACTERISTICS and ATTRIBUTES OF COMPUTER VIRUSES The demonstrated characteristics of computer viruses include several remarkable items, including size, versatility, propagation, effectiveness, functionality, and persistence. 1) Size.The sizes of the program code required for computer viruses has been demonstrated to be surprisingly small. This has facilitated the ability of these programs to attach themselves to other applications and escape notice for long periods of time. 2) Versatility.computer viruses have appeared with the ability to generically attack a wide variety of applications. Many do not even require information about the program they are infecting. 3) Propagation. Once a computer virus has infected a program, while this program is running, the virus is able to spread to other programs and files accessible to the computer system. The ability to propagate is essential to a virus program. 4) Effectiveness. Many of thecomputer viruses that have received widespread publicity have had far-reaching and catastrophic effects on their victims. These have included total loss of data, programs, and even the operating systems. 5) Functionality. A wide variety of functions has been demonstrated in virus programs. Some virus programs merely spread themselves to applications without otherwise attacking data files, program functions, or operating systems activities. Other virus programs are programmed to damage or delete files and systems. The effectiveness of these programs is enhanced through the use of several phases of operation, in which the virus propagates through a system or lies dormant until triggered by a specified event. This allows the virus program increased time to spread before the victim system's user becomes aware of its presence. 6) Persistence. Even after the virus program has been detected, recovery of data, programs, and even system operation has been difficult and time consuming. In many cases, especially in networked operations, eradication of viruses has been complicated by the ability of the virus program to repeatedly spread and reoccur through the networked system from a single infected copy.
  • 45. COMPUTER OPERATIONS PACKAGES rmmakaha@gmail.com 44 Attributes of computer viruses o Auto replicating [self replicating]. o Attaches itself to a program or file o It infects as it travels o Reproduces itself o Distribute itself o Copies itself o Duplicate copies of itself o It spreads o It is software o It can destroy o It hides DESTRUCTIVE EFFECTS OF COMPUTER VIRUSES o Cause damage to data o Extract data from machines for spying or theft o Slow machine performance o Corrupt data o Damage software, hardware and files o Damage the computer by damaging programs o Reformatting of the hard disk o Deletion of files ANTIVIRUS TOOLS/PACKAGES/SOFTWARE 1) Dr Solomon’s Antiviral Package 2) Norton Antivirus Package 3) AVG Antivirus 4) Microsoft Antiviral Package 5) McAfee VirusScan 6) F-PROT anti-virus package 7) Protector Plus 2000 for Windows ver 7.2.H03 8) Anti Trojan Elite ver 3.7.5 9) Panda Antivirus platinum 7 ver 7.06 10) AntiSpy ver 4.4.2 11) avast! 4 Professional Edition ver 4.6.652 12) DrWeb® Anti-Virus, Home Edition ver 4.30a 13) Dr.Web Anti-Virus for Workstations ver 4.30.a 14) File Sharing Sentinel ver 1.0.1 15) Real Password Protector 2005 ver 2.0 16) Code(Red) Hunter v1.5 ver v1.5 17) Digital Patrol ver 5.00.12 18) BitDefender 19) Kaspersky 20) F-Secure Anti-Virus 21) PC-cillin 22) ESET Nod32 23) CA Antivirus 24) Norman Virus Control 25) AntiVirusKit 26) AVAST! 27) Panda Titanium 28) Windows OneCare 29) ViRobot Expert 30) PCTools AntiVirus 31) WinAntiVirus 32) CyberScrub AntiVirus 33) The Shield AntiVirus
  • 46. COMPUTER OPERATIONS PACKAGES SCANNER – examine every file on a specific disk drive, looking/searching for known virus “signatures”. A “signature” is a string of software code that identifies a virus program. Every virus has a unique signature MEASURES/FACILITIES PROVIDED BY AN ANTIVIRUS PACKAGE. 1. Scanning – searching for viruses 2. Cleaning of the system (removal of viruses) 3. Rearrangement of corrupted data. 4. Repairing of corrupted data files. 5. Quarantine – separation of infected files from uninfected files. 6. Prevention includes creating user awareness, implementing hygiene rules, using disk authorization software, or providing isolated 'quarantine' PCs. 7. Detection involves the use of anti-virus software to detect, report and (sometimes) rmmakaha@gmail.com 45 disinfect viruses.. 8. Containment involves identifying and isolating the infected items. 9. Recovery involves disinfecting or removing infected items, and recovering or replacing corrupted data. PRECAUTIONS/SAFETY GUIDES AGAINST VIRUSES Install a reliable antiviral package Avoid Software piracy thus buy software from authorized dealers. Never download unknown files from the internet Boot the system from virus free disks Using write protect tabs on floppy disks Scan every floppy diskette for viruses before use. Unknown floppy diskettes should not be used Avoid using foreign storage media Use genuine software Avoid opening e-mails from suspicious or unknown sources Write protect disks Install antivirus software, e.g. Avira, Eset Nod32, AVG, Norton, Dr. Solomon’s Toolkit • Install a reliable anti virus program – From the first moment you turn your computer on, you should have a trusted anti virus program by your side. Even if you have a machine that isn’t hooked up to the Internet, a reliable anti virus program is a low cost and common sense addition to any machine. There are even free anti virus programs you can download that work almost as well as industry giants like Norton and McAfee. • Install anti-spyware and anti-malware programs – As good as the best anti virus programs are, they sometimes need a little bit of help. Thankfully, many of the top anti-spyware programs are completely free. Spybot Search and Destroy and CCleaner are just two free programs that can help prevent computer viruses from doing any damage on your machine. As helpful as these programs are, however, you must update them and run them on a regular basis for them to do any good. • Avoid suspicious websites – A good virus protection program will alert you when you visit a website that attempts to install or run a program on your computer. Many less than reputable adult websites do this, so if you get a warning, don’t go back, you may end up with a bug you can’t get rid of. • Never Open Email Attachments Without Scanning Them First – The most common way viruses are spread throughout the Internet is still via email. Some attachments, like pictures, now display in emails and don’t require an attachment to be manually opened, but other documents do. Make sure you use an email client that scans all email attachments before you are allowed to open them. This will help prevent computer viruses from getting a foothold on your machine. • Set up Automatic Scans – Many of the top anti virus programs, as well as the best anti-spyware programs, now have settings that will let them automatically run during down times or in the middle of the night. Of course, your computer must be on for this to happen, but having daily scans run when nothing else is going on is a great way to prevent even the latest computer viruses
  • 47. COMPUTER OPERATIONS PACKAGES from sticking around too long. • Watch Your Downloads – Part of the fun of the Internet is downloading music, movies and other items. However, since these downloads are so massive, it can be easy to sneak a virus along for the ride. Only download these files from trusted sites that you can count on, or, at the very least, scan them before you open them. • Updates, Updates, Updates – There is a reason why Windows has a feature called Critical Updates. There is an entire branch of Microsoft dedicated to staying one step ahead of the hackers out there so when they manage to fix a possible security loophole, you need to download the patch right away. Help Microsoft help you prevent computer viruses from causing too much trouble. • Know What To Look For – Even if you are just a casual computer user, you should have an idea of how your machine operates, what normal pop up windows look like and what popular viruses are out there, that way, when your computer begins exhibiting tell tale signs, you’ll know. You can help prevent computer viruses by staying updated and educated. • Stay Away From Cracked Software – It is so secret that you can download illegal, cracked versions of some programs online. As tempting as it may be, these files are almost always infested with advanced and difficult to detect bugs. Play it safe and get your software from the source. • Install a Firewall – A firewall is a program that screens incoming Internet and network traffic. Along with your virus program, it can help prevent unauthorized access to your computer. • Be prepared to Lock Down – If you hear of a virus that is spreading like wildfire through the Internet, make an extra effort to be careful. Don’t open any suspicious emails or accept any downloads for a week or two until your virus protection program has been updated and you are, once again, safe. rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 46 COMPUTER LANGUAGES (a) Machine Language A computer language made up of binary digits (0s and 1s) The most fundamental way to program a computer, using instructions made up entirely of strings of 0sand 1s. The language is far from English and any mathematical notation. Machine language is not portable and is machine dependent meaning it cannot be moved from one machine to the other. Errors are very difficult to remove and programs are difficult to write using machine language. (b) Low Level Language Low level means the language can better communicate with the system. LLL are closer to machine code They use mnemonics i.e. ADD to add SUB to subtract etc Easier for a programmer to write a program in LLL than machine language. Programs have to be translated from source code into machine language (c) High Level Language A programming language that utilizes macroinstructions and statements that closely resembles human language or mathematical notation to describe the problem to be solved or the procedure to be used. Programs are much easier to write / read because the are next English [English like statements]. A programming language where each instruction corresponds to several machine code instructions. A compiler or interpreter must translate instructions in this language before they can be processed. MACHINE LANGUAGE ADVANTAGES DISADVANTAGES • A very powerful language • No translation is needed • Much harder to code for programmers because it’s a series of 1s 0s. • Not portable • Machine Dependent • Errors are difficult to remove LOW LEVEL LANGUAGE
  • 48. COMPUTER OPERATIONS PACKAGES ADVANTAGES DISADVANTAGES • Easier to use than machine language • Machine dependent • Harder to code than HLL • Not portable HIGH LEVEL LANGUAGE ADVANTAGES DISADVANTAGES • It is a portable language • Programs are much easier to read/ write coz it’s close to English language. • Programs are problem oriented. • Errors are removed before translation to Machine code [during compiling]. • Slower in execution • Programs tend to be wordy hence they take long to compile. • Requires more memory. LANGUAGE TRANSLATOR PROGRAMS A Translator is a program that translates a source program/code into an equivalent object code [machine code] before the program is executed by the computer. rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 47 Compiler Translates a complete program written in HLL into machine code before it is executed. Produces a translated document. E.g. COBOL compiler. Assembler Translates a source program written in assembly language into machine code. Interpreter A computer program that translates one statement at a time [source code] and generates the machine code for that statement only executes it there there before moving to the next line/statement. Interpreter translates line per line and does not produce a translated document. E.g. Pascal Interpreter, BASIC Interpreter. Compare contrast Interpreter Compiler 1) Compiler- fast execution of program. 2) Interpreter- Slowed down execution of program. 3) Compiler- compiler time overhead. 4) Interpreter- No compiler time overhead 5) Compiler- Stand alone executables 6) Interpreter- Dependency on interpreter 7) Compiler- Compiler is complex [time, space] 8) Interpreter- Relative simplicity of interpreter List the advantages disadvantages of interpreters compilers. 1. A compiled program will always run faster than an interpreted one 2. Object code generated by compilers may be saved on disk run as many times as required without being compiled. 3. A compiler gives more helpful error messages. 4. Compiler gives the line number where the error has occurred. 5. An interpreter will find the error at the first instance whereas the compiler will list all errors after compiling. 6. A compiler will check the syntax of the entire program whereas the interpreter only checks the syntax of statements that are executed during that particular run of a program. 7. Interpreters are very convenient for program development, since making modifications does not mean the whole program has to be reloaded recompiled which takes considerable time. 8. Interpreter is cheaper than compiler is simpler to use
  • 49. COMPUTER OPERATIONS PACKAGES 9. Many interpreters will allow a program to run up to a point where an error occurs, let the programmer fix the error then continue to run the program from that point. 10. With an interpreter debugging is easier since the code is executed line by line. 11. Line by line interpretation can be slow 12. Interpreter can test your code as you write it 13. With an Interpreter there is no need to create object code link programs. Language Processors and Translator Programs • These are programs that are used to convert high and low level language programs into machine code, i.e. into a form directly understood by the computer. There are three main types of translator programs: • Human programmers write programs in a language that is easy to understand for them • They use language translators to convert that program into machine language – a language that is easy to understand for the processor Translation process rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 48 Source code (Human readable) a) Assemblers They translate programs written in assembly language into machine code b) Interpreters Convert HLL programs into machine by translating one program statement at a time before it can be executed. No object code is stored, e.g. QBASIC Interpreter translates the HLL program one statement at time. It reads a single statement, translates it into machine language and passes that machine language code to the processor and then translates the next statement, and so on … c) Compilers Like interpreters they also translate HLL programs into machine code. They however differ from interpreters in that a whole program is translated at a time. The object code which is created can either be executed immediately or saved for later execution. Compiler translates the program written in a HLL in one go. The translated code is then used by the processor whenever the program needs to be run Development Software/Programming Languages It allows the user to create software for various applications. All software programmes (systems and application) are written in coding schemes called programming languages. The primary function of a programming language is to provide instructions to the computer system so that it can perform a processing activity to achieve an objective or solve a problem. Programme code is the set of instructions that signal the CPU to perform circuit-switching operations. Programming languages have four categories: • Low-level languages • High-level languages • Fourth generation languages • Fifth generation languages Object code (Machine readable)
  • 50. COMPUTER OPERATIONS PACKAGES rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 49 Low Level Languages • Low level computer languages are machine codes or close to it. • Computer cannot understand instructions given in high level languages or in English. It can only understand and execute instructions given in the form of machine language i.e. language of 0 and 1. • There are two types of low level languages. The lowest-level language is Machine Language, which hides no details of the machine; not even the bit patterns used to form instructions are abstracted. • Low-level languages have the advantage that the programmer is able to tune the code to be smaller or more efficient, and that more system-dependent features are sometimes available. They have the disadvantage that they are often (usually?) harder to program with than HLLs. First generation languages (abbreviated as 1GL) • The most elementary and first type of computer, which was invented, was machine language. Machine language was machine dependent. • A program written in machine language cannot be run on another type of computer without significant alterations. Machine language is sometimes also referred as the binary language i-e, the language of 0 and 1 where 0 stands for the absence of electric pulse and stands for the presence of electric pulse. Very few computer programs are actually written in machine language. • It is the lowest and most elementary level of programming language and was the first type of programming language to be developed. Machine language is basically the only language which computer can understand. • In fact, a manufacturer designs a computer to obey just one language, its machine code, which is represented inside the computer by a string of binary digits (bits) 0 and 1. The symbol 0 stands for the absence of electrical pulse and 1 for the presence of an electrical pulse. Since a computer is capable of recognizing electric signals, therefore, it understands machine language. • Represent the very early, primitive computer languages that consisted entirely of 1's and 0's - the actual language that the computer understands (machine language). • The main benefit of programming in machine code is that the code a user writes can run very fast and efficiently, since it is directly executed by the CPU. However, machine code is a lot more difficult to learn than higher generational programming languages, and it is far more difficult to edit if errors occur. Advantages of Machine Language i) It makes fast and efficient use of the computer. ii) It requires no translator to translate the code i.e. directly understood by the computer Disadvantages of Machine Language:
  • 51. COMPUTER OPERATIONS PACKAGES i) All operation codes have to be remembered ii) All memory addresses have to be remembered. iii) It is hard to amend or find errors in a program written in the machine language iv) These languages are machine dependent i.e. a particular machine language can be used on only one type of computer Second generation languages (2GL) – Assembly Language • As computer became more popular, it became quite apparent that machine language programming was simply too slow tedious for most programmers. Assembly languages are also called as low level language instead of using the string of members programmers began using English like abbreviation to represent the elementary operation. • The language provided an opportunity to the programmers to use English like words that were called MNEMONICS. • It was developed to overcome some of the many inconveniences of machine language. This is another low level but a very important language in which operation codes and operands are given in the form of alphanumeric symbols instead of 0’s and l’s. • These alphanumeric symbols will be known as mnemonic codes and can have maximum up to 5 letter combination e.g. ADD for addition, SUB for subtraction, START,LABEL etc. Because of this feature it is also known as ‘Symbolic Programming Language’. This language is also very difficult and needs a lot of practice to master it because very small • English support is given to this language. The language mainly helps in compiler orientations. The instructions of the Assembly language will also be converted to machine codes by language translator to be executed by the computer. • It represents a step up from the first generation languages. Allow for the use of symbolic names instead of just numbers. Second generation languages are known as assembly languages. Code written in an assembly language is converted into machine language (1GL). • Assembly language consists of letters of the alphabet. This makes programming much easier than trying to program a series of zeros and ones. As an added programming assist, assembly language makes use of mnemonics, or memory aids, which are easier for the human programmer to recall than are numerical codes. Advantages of Assembly Language i) It is easier to understand and use as compared to machine language. ii) It is easy to locate and correct errors. iii) It is modified easily rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 50
  • 52. COMPUTER OPERATIONS PACKAGES Disadvantages of Assembly Language i) Like machine language it is also machine dependent. ii) Since it is machine dependent therefore programmer Should have the knowledge of the hardware also. rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 51 High Level Languages • The assembly languages started using English like words but still it was difficult to learn these languages. High level languages are the computer language in which it is much easier to write a program than the low level language. • High level computer languages give formats close to English language and the purpose of developing high level languages is to enable people to write programs easily and in their own native language environment (English). High-level languages are basically symbolic languages that use English words and/or mathematical symbols rather than mnemonic codes. Each instruction in the high level language is translated into many machine language instructions thus showing one-to-many translation Advantages of High Level Language • User-friendly • Similar to English with vocabulary of words and symbols • They require less time to write. • They are easier to maintain. • Problem oriented rather than 'machine' based. • Program written in a high-level language can be translated into many machine language and therefore can run on any computer for which there exists an appropriate translator. • It is independent of the machine on which it is used i.e. Programs developed in high level language can be run on any Computer • Easier to learn and understand than an assembler language as instructions (statements) that resemble human language or the standard notation of mathematics. • Have less-rigid rules, forms, and syntaxes, so the potential for error is reduced. • Are machine-independent programs therefore programs written in a high-level language do not have to be reprogrammed when a new computer is installed. • Programmers do not have to learn a new language for each computer they program. • Instructions are much easier to remember and use that assembly language instructions • Fewer instructions are required to write a program than when using assembly language. • A program can usually be developed much more quickly using a high level language than an assembly language. • A program written in a high level language on one type of computer can usually be converted to operate on another type of computer quite easily. Because of this high level language programs are described as being portable. • Disadvantages of High Level Language • A high-level language has to be translated into the machine language by a translator and thus a price in computer time is paid.
  • 53. COMPUTER OPERATIONS PACKAGES • The object code generated by a translator might be inefficient Compared to an equivalent assembly language program • Types of computer languages - as we human beings communicate with each others in different language such as Urdu, French, Punjabi and Arabic etc. Similarly to communicate with the computers we have to use specific languages and for this purpose hundreds of languages have been developed • Less efficient than assembler language programs and require a greater amount of computer time for translation into machine instructions. • High level language programs normally take up more space and execute more slowly than equivalent assembly language programs Types of High Level Languages Many languages have been developed for achieving different variety of tasks, some are fairly specialized others are quite general purpose. These are categorized according to their use as a) Algebraic Formula-Type Processing. These languages are oriented towards the computational procedures for solving mathematical and statistical problem Examples are • BASIC (Beginners All Purpose Symbolic Instruction Code). • FORTRAN (Formula Translation). • PL/I (Programming Language, Version 1). • ALGOL (Algorithmic Language). • APL (A Programming Language). rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 52 b) Business Data Processing: • These languages emphasize their capabilities for maintaining data processing procedures and files handling problems. Examples are: • COBOL (Common Business Oriented Language). • RPG (Report Program Generator b) String and List Processing: These are used for string manipulation including search for patterns, inserting and deleting characters. Examples are: • LISP (List Processing). • Prolog (Program in Logic). Object Oriented Programming Language In OOP, the computer program is divided into objects. Examples are: • C++ • Java e) Visual programming language: these are designed for building Windows-based applications Examples are: • Visual Basic • Visual Java
  • 54. COMPUTER OPERATIONS PACKAGES rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 53 • Visual C Third generation languages (3GL) With the languages introduced by the third generation of computer programming, words and commands (instead of just symbols and numbers) were being used. These languages therefore, had syntax that was much easier to understand. • Third generation languages are known as high level languages and include C, C++, Java, and JavaScript, among others. Fourth generation languages (4GL) § The syntax used in 4GL is very close to human language, an improvement from the pervious generation of languages. 4GL languages are typically used to access databases and include SQL and ColdFusion, among others. VERY HIGH LEVEL LANGUAGES (VHLL) Fifth generation languages (5GL) Fifth generation languages are currently being used for neural networks. A nueral network is a form of artificial intelligence that attempts to imitate how the human mind works. • 5GL is an abbreviation for fifth-generation language. Fifth-generation programming languages emerged along with the research in Artificial Intelligence (AI). Most constraint-based and logic programming languages and some declarative languages are fifth-generation languages. Fifth-generation languages are designed to make the computer solve the problem for you as oppose to using an algorithm written by a programmer. • The idea of fifth generation languages was popular in 1990s. Japan put much research and money into their fifth-generation computer systems project. Prolog, Mercury, and OPS5 are the best known fifth-generation languages. • These are used to create programs for artificial intelligence and expert system and are sometimes called natural languages because they use English syntax. Allow programmers to communicate with the computer using normal sentences. GENERIC SOFTWARE AND THE ORGANISATION OF DATA Define Software Are basically programs, which are in a computer system?
  • 55. COMPUTER OPERATIONS PACKAGES Computer programs and procedures concerned with the operation of a computer system. Definitions of software on the Web: • Written coded commands that tell a computer what tasks to perform. For example, Word, PhotoShop, Picture Easy, and Photo Deluxe are software programs. • Coded instructions (programs) that make a computer do useful work. Computer software refers to the various programs or instructions that are stored in the computer (stored program concept) and used to either manage or control the operation of a computer system or to direct the computer in solving specific problems. Software is divided into two major types. rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 54 SOFTWARE HIERARCHY TYPES OF SOFTWARE
  • 56. COMPUTER OPERATIONS PACKAGES rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 55 SYSTEM SOFTWARE • Refers to the operating system and all utilityprograms that manage computerresources at a low level. Programs that control and support operations of a computer system. • Systems software includes compilers, loaders, linkers, and debuggers. • System software includes a variety of programs such Operating Systems, DBMS, Communication control programs. Service and utility programs, and programming language translators. • Definitions of system software A term for a complicated set of programs that act together to allow a computer, and other programs, to function. Different from an page layout application that the user may have, system software is what allows the page layout application to interact with the monitor display, the RAM, the hard drive and the rest of the computer. OPERATING SYSTEM • The main control of a computer system. • It is a system of programs that controls coordinates the execution of computer programs and may provide scheduling, debugging, input/output control, system accounting, compilation, storage assignment, data management and related services. Definitions of operating system on the Web: • The software that the rest of the software depends on to make the computer functional. On most PCs this is Windows or the Macintosh OS. Unix and Linux are other operating systems often found in scientific and technical environments. • A computer program that controls the components of a computer system and facilitates the operation of applications. Windows Me, Windows XP, Linux, and MacOS are common operating systems. APPLICATION SOFTWARE o Applications software comprises programs designed for an end user, such as word processors, database systems, and spreadsheet programs. o Programs that specify the information processing activities required for the completion of specific tasks of computer users. E.g. Electronic Spreadsheet and word processing programs or inventory or payroll programs.
  • 57. COMPUTER OPERATIONS PACKAGES o Software that is designed and written for a specific personal, organizational, or processing task, such as graphics software. o These programs accomplish the specialized tasks of the user, while operating system software allows the computer to work. A computer-aided dispatch system is application software, as is each word processing program. rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 56 FREEWARE Public domain softwarethat is freely available in magazines and on the internet at no charge to users though manuals may be offered at a cost. Freeware may or may not have copyrights and may or may not have distribution restrictions. SHAREWARE Refers to software that is widely distributed in much the same way as freeware BUT is always copyrighted and includes a software license that requires its users to pay for the privilege of using the software beyond a certain trial period. If you decide to use it, you are expected to pay for the license. There is usually a disabling system in the program after a certain period of time i.e. a month. OPERATING SYSTEM Are programs that create an environment, which enables us to use computers? Is an integrated system of program that manages the operations of the CPU, controls the input/output and storage resources and activities of the computer system, and provides various support services as the computer executes the application programs? Is a set of software routines that communicate between application programs and the hardware? All communications go through the operating system. E.g. when a user issues a command to print, the O/S receives the command processes it according to priorities with the use of interrupts. Once the processor is free to execute the command, the O/S sends the message to the processor receives the output, which is then directed to the printer. MAJOR OPERATING SYSTEMS MS-DOS (Microsoft Disk Operating System) • It has been widely used especially before 1995 when the new Windows 95 took over. • It is a single user operating system – only one user can be using the system at a given time. • It is a single tasking operating system – It allows for the processing of only one task at a time • Use of short prompt commands – the user interfaces with the computer system through the use of commands that are fed into the computer usually after the prompt sign () e.g. C:cls (Command to clear the screen) • Instructions are put in only through the keyboard • Once a file is deleted it can never be recalled • The operating system is not user-friendly Windows • A windows based operating system is more advanced than the MS-DOS based operating system. • It features graphical user interfaces (GUIs) – User can feed commands into the computer through the selection of relevant icons, bars, buttons, boxes or other forms of images (mostly resembling the intended device or operation). • True multitasking – the operating system allows for numerous tasks to be done at the same time. • Networking – the operating system is multi-usable – many users can use it at the same time. It is capable of holding a number of computer systems networked together.
  • 58. COMPUTER OPERATIONS PACKAGES • Multimedia Presentations- the operating system allows for the presentation of information in a variety of media including text, graphic displays, voice and other audio, photographs and video. • Virtual Memory – It allows for the use of storage devices as extension of the main memory thus giving the appearance of a larger main memory than actually exists. • Deleted files go to the recycle bin • Makes use of easier input methods, e.g. mouse, joystick • Windows operating system has MS-DOS option • Examples of Windows Operating Systems packages, Windows NT (new technology) and rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 57 Windows 95. • In computer terms, a window is one section of a computer’s multiple section display screen that can have a different display. OS/2 • It is called the Operating System /2 • It is an operating system developed by IBM and was introduced in 1994 with the OS/2 Warp version as the latest one. • It provides graphical user interfaces (GUIs), multitasking, virtual memory and telecommunications. UNIX • Originally developed by ATT but now being offered by many other vendors. • It is a multitasking, multi-user and net-work managing operating system • Because of its portability, it can be used on mainframes, midrange computers and microcomputers. • It is a popular choice for network servers. The Macintosh System/Mac OS • It is an operating system for Apple from Macintosh microcomputers • It is a popular GUI as well as multitasking and virtual memory operating system. Types /EXAMPLES of operating systems There are several types of operating system, defined according to whether they can simultaneously manage information measuring 16 bits, 32 bits, 64 bits or more. OPERATING SYSTEM PROGRAMMING SINGLE USER MULTI USER SINGLE TASK MULTI TASK 1. MS DOS 16 bits X X 2. Windows3.1 16/32 bits X not pre-emptive 3.Windows95/98/Me 32 bits X cooperative 4.WindowsNT/2000 32 bits X pre-emptive 5.WindowsXP 32/64 bits X pre-emptive 6.Unix / Linux 32/64 bits X pre-emptive 7.MAC/OS X 32 bits X pre-emptive 8.VMS 32 bits X pre-emptive 9.Windows Vista 10.Windows 7
  • 59. COMPUTER OPERATIONS PACKAGES BOOTING(also known as booting up) is a bootstrapping process that starts operating systems when the user turns on a computer system. A boot sequence is the initial set of operations that the computer performs when power is switched on. The bootloader typically loads the main operating system for the computer. rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 58 Rebooting Hard reboot A hard reboot (also known as a cold reboot, cold boot or cold start) is when power to a computer is cycled (turned off and then on) or a special reset signal to the processor is triggered. This restarts the computer without first performing any shut-down procedure. (With many operating systems, especially those using disk caches, after a hard reboot the filesystem may be in an unclean state, and an automatic scan of on-disk filesystem structures will be done before normal operation can begin.) It may be caused by power failure, be done by accident, or be done deliberately as a last resort to forcibly retrieve the system from instances such as a critical error or virus-inflicted DoS attack. It can also be used by intruders to access cryptographic keys from RAM, in which case it is called a cold boot attack. Soft reboot A soft reboot (also known as a warm reboot) is restarting a computer under software control, without removing power or (directly) triggering a reset line. It usually, though not always, refers to an orderly shutdown and restarting of the machine. The Control-Alt-Delete key combination on the original IBM PC was designed to allow a soft reboot for a quicker and more convenient (and, some argue[who?], less stressful on system components) restart than powering the computer completely down then back up. This kind of reboot will not usually reset the hard disks, so that they have time to update their write cache to permanent storage. Hard disks will also keep their configuration (like C/H/S adjustments, HPA, DCO, internal passwords...) over these reboots. The Linux kernel has optional support for the kexecsystem call, which transfers execution to a new kernel and skips hardware or firmware reboot. The entire process is done independent of the system firmware. Note that the kernel being executed does not have to be a Linux kernel. Sometimes, the computer does not respond and in that case it can be restarted by pressing Ctrl+Alt+Del keys. The process of starting the computer using these keys is called warm booting or softbooting. Random reboot Random reboot is a non-technical term referring to an unintended (and often undesired) reboot for which the cause is not immediately evident to the user. Such reboots may occur due to a multitude of software and hardware problems, such as triple faults. As Windows XP/Vista has an option to skip its Blue Screen of Death (Blue Screens of Death in Windows XP/Vista offer no option of pressing any key and seeing if the computer continues functioning) and immediately restarts the computer in the event of a fatal error, users can be mistaken in thinking a Windows XP/Vista computer suffers from random rebooting. Also, If a Wii game has a disc failure or the Wii game disk is dirty, it will reboot to the Wrist Strap screen. Errors In Windows, when an error occurs in the boot process, a Blue Screen of Death or a Black Screen of Death may occur. On UNIX and Unix-like operating systems, such as Linux, a fatal error in the boot process may cause a kernel panic. FACTORS ONE SHOULD CONSIDER WHEN • Making comparisons of the microcomputer operating systems available in the organization • Making microcomputer operating system acquisition decision.
  • 60. COMPUTER OPERATIONS PACKAGES Is the OS a single or multitasking operating system? Many microcomputer OS are single tasking, meaning they allow only one person to run one program at a time. Multitasking and multi-user OS permit more than one program to run and more than one person to use the system at one time. Multitasking OS may allow a user to receive a fax message at the same time one is searching a database. Is it a task switching operating system? A task switching OS lets one load more than one program at a time and allows switching between the programs. The task that one is working with is the foreground task and the suspended tasks are background tasks. What utilities are available with the OS? Some of the most commonly used utilities on microcomputer OS are delete, copy contents of one diskette to another, format a diskette, delete files stored in a diskette, and compress data. Is the OS hardware dependent? An OS may be limited to running on specific hardware or may have versions that allow it to run on different types of computer systems. What user interface is offered by the operating system? Graphical User Interface and Command Driven User Interface are examples of user interfaces. See Interface section. Types of operating systems Multiprocessing Multitasking Multi-user Multi programming Single user Modes of operation/ Operating system techniques Computers can operate in many different ways requiring different and complex operating systems. rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 59 Real time processing When the computer has to react within a guaranteed time to an input, a real time operating system is used. For example, the engine management system within a car uses a real time operating system in order to react to all the things going on within the engine. A real time operating system does not necessarily have to be fast. It simply has to be quick enough to respond to inputs in a predictable way. Embedded computers often contain an RTOS as many are used to control something. Computers operating in real time are often dedicated to the control of systems such as industrial processes, planes and space flights. Another example of real time processing is computer games. For example, when an action is selected in a game, the data is fed back to the computer and the systems updated. Multi-programming Multi-programming is a method of operating such that several programs appear to be running at once. The jobs are usually given priorities. The operating system switches jobs in and out of processor time according to priority. For example, while one job is being allocated printer time, another will be being processed in memory. The processor is so fast that it seems that many jobs are being processed at the same time. Multi-tasking This isn't just about running more than one application at the same time. Multi-tasking allows multiple tasks to run concurrently, taking turns using the resources of the computer. This can mean running a couple of applications, sending a document to the printer and downloading a web page. However, operating systems are not truly multi-tasking - in order to do this, you would need parallel processors, which are now appearing on personal computers. Multiprocessing An operating system technique which can manage multiple instruction processors, assigning each to operate upon a different instruction stream (program or job) concurrently.
  • 61. COMPUTER OPERATIONS PACKAGES Multiprocessing is the use of two or more central processing units (CPUs) within a single computer system. The term also refers to the ability of a system to support more than one processor and/or the ability to allocate tasks between them.[1] There are many variations on this basic theme, and the definition of multiprocessing can vary with context, mostly as a function of how CPUs are defined (multiple cores on one die, multiple chips in one package, multiple packages in one system unit, etc.). Multiprocessing sometimes refers to the execution of multiple concurrent software processes in a system as opposed to a single process at any one instant. However, the terms multitasking or multiprogramming are more appropriate to describe this concept, which is implemented mostly in software, whereas multiprocessing is more appropriate to describe the use of multiple hardware CPUs. A system can be both multiprocessing and multiprogramming, only one of the two, or neither of the two. rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 60 Multi-access or multi-user A multi-access (or multi-user) system is one where a number of users are able to use the same system together. Modern personal computers can allow multi user access i.e. more than one person can make use of the computer resources at the same time via a LAN. The central processor deals with users in turn; clearly the more users, the slower the response time. Generally, however, the processor is so fast that the response time at the most is a fraction of a second and the user feels they are being dealt with immediately. o Multi-user is a term that defines an operating system or application software that allows concurrent access by multiple users of a computer. Time-sharing systems are multi-user systems. Most batch processing systems for mainframe computers may also be considered multi-user, to avoid leaving the CPU idle while it waits for I/O operations to complete. However, the term multitasking is more common in this context. o An example is a UNIX server where multiple remote users have access (such as via Secure Shell) to the UNIX shell prompt at the same time. Another example uses multiple X Window sessions spread across multiple terminals powered by a single machine - this is an example of the use of thin client. o Management systems are implicitly designed to be used by multiple users, typically one system administrator or more and an end-user community. Single-user Is most commonly used when talking about an operating system being usable only by one person at a time, or in reference to a single-user software license agreement. Multi-user operating systems such as UNIX sometimes have a single user process available for emergency maintenance. Batch processing A batch processing system is where programs or data are collected together in a batch and processed in one go. Typically the processing of payrolls, electricity bills, invoices and daily transactions are dealt with this way. This method of operation lends itself to jobs with similar inputs, processing and outputs where no human intervention is needed. Jobs are stored in a queue until the computer is ready to deal with them. Often batch processed jobs are done overnight. ROLES (functions) OF THE OPERATING SYSTEM The operating system has various roles: 1. Management of the processor: the operating system is responsible for managing allocation of the processor between the different programmes using a scheduling algorithm. The type of scheduler is totally dependent on the operating system, according to the desired objective. The OS is responsible for managing the allocation of processor time to the different programs that will be using the computer. The processor can only execute one instruction at a time and in a multi-user system, conflicts are bound to arise when several user programs request usage of the processor at the same time. The OS
  • 62. COMPUTER OPERATIONS PACKAGES therefore allocates processor time to all users either in a round robin fashion or using a system of priorities. 2. Management of the random access memory: the operating system is responsible for managing the memory space allocated to each application and, where relevant, to each user. If there is insufficient physical memory, the operating system can create a memory zone on the hard drive, known as virtual memory. The virtual memory lets you run applications requiring more memory than there is available RAM on the system. However, this memory is a great deal slower. The OS is responsible for managing the memory space allocated to each application. If there is insufficient physical memory the OS can create a memory zone on the hard drive known as virtual memory which lets you run applications requiring more memory than is available on the system. The operating system is responsible for the following activities in connections with memory management. Keep track of which parts of memory are currently being used and by whom. Decide which processes to load when memory space becomes available. Allocate and deallocate memory space as needed 3. 4. Management of input/output: the operating system allows unification and control of access of programmes to material resources via drivers (also known as peripheral administrators or input/output administrators). 5. Management of execution of applications: the operating system is responsible for smooth execution of applications by allocating the resources required for them to operate. This means an application that is not responding correctly can be killed. 6. Management of authorisations: the operating system is responsible for security relating to execution of programmes by guaranteeing that the resources are used only by programmes and users with the relevent authorisations. 7. File management: the operating system manages reading and writing in the file system and the user and application file access authorisations. The OS manages reading from and writing to files and also controls the creation, manipulation and access to files. The operating system is responsible for the following activities in connections with file management: File creation and deletion Directory creation and deletion Support of primitives for manipulating files and directories Mapping files onto secondary storage File backup on stable (nonvolatile) storage media 8. Information management: the operating system provides a certain number of indicators that can be used to diagnose the correct operation of the machine. rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 61 9. ERROR DETECTION The OS is responsible for detecting and any hardware or software malfunctioning and reporting them to the user 10. USER/SYSTEM INTERFACE The OS acts as an interface between the computer and the user, hiding all the complexities of the computer from the user and making the computer more user friendly 11. PREPARATION OF A SYSTEM LOG The OS compiles a report on the events that take place in a computer from the time a user logs on to a computer, what he/she does up to the time he/she logs off Additional Functions of the operating system: Controls and coordinates the computer system
  • 63. COMPUTER OPERATIONS PACKAGES Scheduling and loading of jobs to provide continuous processing. So that no parts of the computer system are idle for any significant period of time. It is a platform for application programs Provides user interface Acts as an interface between hardware and application programs Provides error correctional routines Control over selection and operation of input Records details of processing for control analysis File management, control the creati Memory management, allocates memory to various jobs or tasks Multiprogramming, multiprocessing, multitasking, timesharing, housekeeping handling errors. input-output devices file handling. creation, deletion, saving and access of files Resource management manages processor time, memory space, di peripheral devices. Reports errors when they occur. Task management. Manage the accomplishment of the computing tasks of end users. It may involve multitasking capability where several computing tasks can occur at the same time. Minimizes the amount of human intervention required during processing. COMPUTER INTERFACE Refers to the type of interaction between two elements. Is part of the operating system that allows you to communicate with it or the computer so that you can load programs, When a person interacts with a computer he uses a User Interface, which can be a screen, keyboard, mouse, scanners or other input devices. Definitions of interface on the Web: • The interaction between the computer a between a computer and its peripherals. Basically the interface can be Command driven provide users with flashes of text and in which users would general their command to perform an action. Menu driven GUI- point and click WIMP interface 1. Command line interfaces (MS A command line interface allows the user to interact with the computer by The computer displays a prompt, the user keys in the comman COMMAND-LINE INTERFACE (CLI) or software by typing commands to perform specific tasks. This text the use of a mouse pointer with a text user interface (TUI) to select options. Features of a command line interface include: In the early days of personal computers, all PCs used command • Commands - usually abbreviated command will not work. • Experienced users who know the commands can work very quickly without having to find their way around menus. rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm disk space and . access files, and accomplish other tasks? and the user or the control of the flow of data driven- include operating systems and database languages that MS-DOS BASED OPERATING SYSTEM) typing in commands command and presses enter or return. A is a mechanism for interacting with a computer operating system text-only interface contrasts with graphical user interface (GUI) to click on options, or menus on a command-line interfaces. - must be typed correctly and in the right order or the 62 sk nd generally type in commands. d )
  • 64. COMPUTER OPERATIONS PACKAGES • An advantage of command driven programs is that they do not need the memory and processing power of the latest computer and will often run on lower spec machines. • Command driven programs do not need to run in Windows. • A command line interface can run many programs, for example a batch file could launch half a dozen programs to do its task. • An inexperienced user can sometimes find a command driven program difficult to use because of the number of commands that have to be learnt. An example of a common command-driven interface is MS-DOS, the original operating system for all Microsoft-compatible PCs. The MS-DOS command to display all files on drive a would be: dir c:. 2. Graphical user interfaces (WINDOWS BASED OPERATING SYSTEM) Graphical user interface is sometimes shortened to GUI. The user chooses an option usually by pointing a mouse at an icon representing that option. A GRAPHICAL USER INTERFACE (GUI) is a type of user interface item that allows people to interact with programs in more ways than typing such as computers; hand-held devices such as MP3 Players, Portable Media Players or Gaming devices; household appliances and office equipment with images rather than text commands. A GUI offers graphical icons, and visual indicators, as opposed to text-based interfaces, typed command labels or text navigation to fully represent the information and actions available to a user. rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 63 Features of GUIs include: • They are much easier to use for beginners. • They enable you to easily exchange information between software using cut and paste or 'drag and drop'. • They use alot of memory and processing power. It can be slower to use than a CLI if you are an expert user. • They can be irritating to experienced users when simple tasks require a number of operations. When discussing user interfaces, it is important to note that Windows XP, OS/X and Linux are all graphical user interfaces. A good user interface should: • be attractive and pleasing to the eye • allow the user to try out different options easily • be easy to use • use suitable colours for key areas • use words that are easy to understand aimed at the type of user • have online help It also should consider the needs of the users. For example, young children are likely to prefer pictures to words and people with disabilities may benefit from particular input or output devices 3. WIMP interface • Windows, Icons, Menus and Pointer - a method by which a user can interact with a computer without having to learn lots of special words - it provides a much more intuitive 'view' of the computer and its facilities than non-WIMP operating systems provide • Windows, /images/, Menus and Pointer, or Windows, /images/, Mouse and Pull-down menus This is a graphical interface which makes access to computers much more straightforward and intuitive than the main alternative, the command-line interface. The
  • 65. COMPUTER OPERATIONS PACKAGES WIMP interface has been used on Apple Macintosh computers since they w and are coming into use on PCs through Microsoft Windows and on Unix and other workstations through the X Window system. 4. Menu driven interfaces The user is offered a simple menu further menu. Part of the screen may have an instruction followed by a numbered list of options to choose from: A full screen menu takes up most of the screen. A menu bar is the set of options at the top of the screen. When an option is chosen a menu may be offered. Features of menu driven interfaces include: • They are easy to use as the user does not have to remember sets of commands. • They are user friendly - you can often guess your way around the options. • They can be irritating if there ar command line interface you can go to the option required immediately. Dialog box In graphical user interfaces, a dialog to display information to the user, or to get a response if needed. They are so form a dialog between the computer and the user requesting input from the user, or both. It provides controls that allow you out an action. Scrollbar A scrollbar (Also known as a handle in the very first GUIs) is a graphical object in a continuous text, pictures or anything else can b viewed even if it does not fit into the space in a Taskbar In computing, taskbar is a desktop display bar used to incorporated a taskbar in Windows 95 graphical user interface ever since. Other include a taskbar. Other operating systems use terms such as Toolbar In a graphical user interface on a buttons, icons, menus or other input or output elements are placed. WYSIWYG WYSIWYG, is an acronym for What describe a system in which content displayed during editing appears very similar to the final output,[2] which might be a printed document, web page, slide presentation or even the lighting for a theatrical event. The phrase was originally a catch phrase (from Rowan Martin's Laugh-In would often say What you see is what you get to excuse her quirky behavior. Meaning WYSIWYG implies a user interface result while the document is being created. In general WYSIWYG implies the ability to directly manipulate the layout of a document without having to type or remember names of layout commands. The actual meaning depends on the user's perspective, e.g. • In Presentation programs display precisely represents the appearance of the pa does not necessarily reflect how the page will be printed unless the printer is specifically matched to the editing program, as it was with the Apple Macintosh. rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm were invented, from which to choose an option. One menu often leads to a r are too many levels of menus to move around - (or dialogue) box is a special window, used in user interfaces so-called because they user—either informing the user of something, or to specify how to carry GUI be scrolled including time in video applications, i.e., computer display, window, or viewport. launch and monitor applications. and it has been a defining aspect of Microsoft Windows desktop environments, such as KDE and GNOME ude Panel or Dock. computer monitor a toolbar is a GUI widget on which onscreen hat You See Is What You Get. The term is used in computing popularized by Flip Wilson's drag persona Geraldine in the late 60s and then on The Flip Wilson Show until 1974), who en that allows the user to view something very similar to the end programs, Compound documents and web pages, WYSIWYG means the page displayed to the end Xerox Star and early versions of the 64 ere pull down with a , with which , Microsoft Windows's GNOME, also to , ge end-user, but
  • 66. COMPUTER OPERATIONS PACKAGES • In Word Processing and Desktop Publishing applications, WYSIWYG means the display simulates the appearance and precisely represents the effect of fonts and line breaks on the final pagination using a specific 500-page document can accurately refer to a reference three hundred pages later. printer configuration, so that a citation on page 1 of a • WYSIWYG also describes ways to manipulate 3D models in aided design, 3D computer graphics design tool used in the theatre industry for pre Menu bar A menu bar is a region where computer menus application-specific menus which provide access to such functions as opening files, interacting with an application, or help. Menu bars are typically present in windows. Menu bar from Mozilla Firefox. SYSTEM SOFTWARE- consists of programs that manage and support a computer system and its information processing activities. T computer system hardware and the application programs of end users. System software is computer software provide a platform for running a The most basic types of system software are: • The computer BIOS and device control the hardware connected to or built into the computer. • The operating system (prominent examples being Linux), which allows the parts of a computer to work together by performing tasks like transferring data between also provides a platform to run high • Utility software, which helps to analyze, configure, optimize and maintain the computer. In some publications, the term system software tools (like a compiler, linker or debugger Computer purchasers seldom buy a computer primarily because of its system software. Rather, system software serves as a useful (even necessary) level of infrastructure code, generally built pre-installed. In contrast to system software, software that allows play games, listen to music, or surf the web is called Types of system software programs System software helps use the operating system and computer system. It includes diagnostic tools, compilers, servers, windowing systems, utilities, language translator, data communication programs, database systems and more. The purpose of system software applications programmer as much as possible from the complexity and specific details of the particular computer being used, especially memory and other hardware features, and such accessory devices as communications, printers, readers, d Specific kinds of system software include: • Loaders • Linkers • Utility software • Desktop environment / Graphical user interface • Shells rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm Stereochemistry, Computer and is the brand name of Cast Software's lighting pre-visualisation of shows. are housed. Its purpose is to house window n, graphical user interfaces These programs serve as a vital software interface between designed to operate the computer hardware and to application software. firmware, which provide basic functionality to operate and Microsoft Windows, Mac OS X ), memory and disks or rendering output onto a display device high-level system software and application software , is also used to designate software develop debugger). users to do things like create text documents, application software. is to insulate the displays, keyboards, etc. 65 , Computer- window- or with hese onality and device. It software. development built-in or
  • 67. COMPUTER OPERATIONS PACKAGES • BIOS • Hypervisors • Boot loaders • Database Management Systems(SQL, NoSQL) If system software is stored on non-volatile memory such as integrated circuits, it is usually termed firmware. 3 functional categories of system software System management programs Programs that manage the hardware, software, and data resources of the computer system during its execution of the various information processing jobs of users. The most important system management programs are operating systems and operating environments, followed by telecommunications monitors Database Management Systems. System support programs Programs that support the operations and management of a computer system by providing a variety of support services. Major support programs are system utilities, performance monitors, security monitors. System development programs Programs that help users develop information system programs and procedures and prepare user programs for computer processing. Major development programs are language translators, programming tools and CASE [computer-aided software engineering] packages. APPLICATION PACKAGES/SOFTWARE Are programs that are or were developed to solve specific user problems? Word processors and spreadsheets fall into this category. Software application packages can be custom built or they can be bought off the shelf. rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 66 # APPLICATION SOFTWARE DESCRIPTION EXAMPLES 1 Word processing software • A word processor is used to produce documents such as letters, memos and reports. The latest versions of word processing software contain many features and can also be used for desktop publishing to create newsletters, brochures, business cards, signs and more. The latest word processing software will allow you to easily type into columns, add pictures and charts to your page, create custom borders, and experiment with a variety of type faces (fonts) in a wide range of sizes. You can even combine different fonts on the same page. • Word processing software offers many exciting formatting and editing features to make your work easier. You can easily check the spelling of a word or the entire document. The built in thesaurus will help you find an alternate word to use. Blocks of text can be easily moved, copied or erased. • Use this kind of tool to create worksheets, type letters, type papers, etc, e.g. MS Word, WordPerfect,.... • Ms word, Word perfect, Word star, • Ms works word processor ,WordPro 2 Spreadsheet software • A spreadsheet is used to manage, analyze and present numeric information. Some common uses of spreadsheet software are financial reports, personal finances and business finances. Spreadsheet programs can also create a chart from the numeric data. • Ms Excel, Lotus 1-2-3
  • 68. COMPUTER OPERATIONS PACKAGES • The working screen is laid out in rows and columns, much like a ledger. The information is typed into a cell. A cell is the intersection of a row and a column. The cell can contain a number, a word or phrase (generally used to identify what the number represents, such as a column or row heading), or a math function or formula. • Spreadsheets allow you to use simple math expressions such as add, subtract, multiply or divide, or advanced math such as the type of calculations performed by architects, engineers, economists and scientists. Spreadsheets also have a special group of built-in formulas, called functions, that let you perform calculations without having to type long, complex formulas. Functions are grouped into categories, such as financial, statistical, engineering, logical, math and trigonometry, database and list management, date and time, and information. • One of the reasons many people use a computer for their spreadsheet projects is because it is easy to change your information once it has been entered. If you change a number, the spreadsheet will automatically recalculate the results. You can also take advantage of this feature to perform a what-if analysis. For example, you input the data for a small business venture you are considering and the spreadsheet calculates your net profit for the first year of business. If you are not pleased with the result, you can change a few numbers to see how the change would affect the outcome. • Use this kind of tool to compute number-intensive problems such as budgeting, forecasting, etc. A spreadsheet will plot nice graphs very easily, e.g. MS Excel, Quattro Pro, Lotus 1-2-3, rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 67 3 Database management software • Allows user to prepare reports based on data found in different records. DBMS is an important managerial decision support tool for managers at all levels of the organization. A database is an organised store of information, for example an address book, list of employees, list of students, customers or items of assets. Database package is used to store records. Data can be sorted or filtered for separate viewing. Also Calculations and comparisons between data items can be done. Popular database packages are: Microsoft Excel, lotus Approach, Paradox, dBase IV, Data Ease. • Use this software to store data such as address, membership and other text information. A database can be used to easily sort and organize records • Ms Access, DbaseIV, Oracle 4 Payroll • Pay plus , Pay well 5 Accounting e.g. Pastel, TurboCash, QuickBooks • Pastel, Tetra 2000 6 Presentation graphics software • Lets users or managers prepare slides containing charts, text and images. Presentation graphics software usually provides libraries of clip art images that can be cut and pasted into a slide to make the slide more attractive and informative. These are applications designed solely for designing graphs and text charts/posters and often used to produce slides for use on overhead projectors, or presentations on computer-projectors. They can also produce various types of charts. Examples of graphics packages are: Microsoft PowerPoint, Lotus Freelance, Harvard Graphics and Corel Draw, HyperStudio, Flash, Director. • Use this software to create multimedia stacks of cards/screens that can effectively present a lesson or a sales pitch. The user often clicks • Ms PowerPoin t, Lotus freelance graphs
  • 69. COMPUTER OPERATIONS PACKAGES on buttons to advance to the next screen in a sequence rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 68 7 Desktop Publishing • Use this software to make signs, banners, greeting cards, illustrative worksheets, newsletters, etc • Desktop Publishing (DTP) applications give users powerful and versatile page design capabilities. The user can incorporate text and graphics on very exact page layouts. These applications produce magazines, catalogues, invitation cards, business cards and other sophisticated documents. It links up well with other applications as the user can import text and graphics from the other applications. Examples of DTP packages are: Microsoft Publisher, PageMaker, Ventura and Frame maker. • Ms publisher, Aldus 8 Multimedia i) Internet Browsers This software allows one to surf the Web. Often they can read email and create Web pages too, e.g. Netscape Navigator (or Netscape Communicator), MS Internet Explorer, AOL Browser.... ii) Email programs These programs send and receive email, e.g. Netscape Messenger (part of Netscape Communicator), MS Outlook Express, MS Outlook, Eudora, AOL browser (has email built in).... iii) Graphics Programs (pixel-based) This software allows one to touch up photographs and create graphics from scratch, e.g Adobe Photoshop, Paint Shop Pro, MS Paint (comes free on Windows PC's), Painter, .... • Internet explorer Netscape 9 Communication • This software allows two computers with modems to communicate through audio, video, and/or chat-based means, e.g. MS NetMeeting, AOL Instant Messenger, IRC, ICQ, CU-SeeMe, ... • Ms Outlook, Ms Exchange 10 Design e.g. AutoCad, Corel Draw • AutoCAD, CAM State five advantages of using a word processor (e.g. MS Word) rather than a manual typewriter in an office [10]. Ability to correct mistakes Ability to view documents on screen before printing Ability to incorporate diagrams Ability to move parts of text to other sections of the document. Ability to save or store documents for future reference or use. Ability to alter or change document layout. Ability to print a lot of copies [ no retyping] Ability to insert tables Ability to format document [font, paragraphs, bullets etc] Spelling and grammar checker Import files Mail merge WYSIWYG capability Creation of templates Automatic creation of index and table of contents o ther - Good reasoning [ 2 marks each for 5 1 mark each for more than 5] a) Explain what is meant by the term ‘word processing package’. [3 marks]
  • 70. COMPUTER OPERATIONS PACKAGES Is a program or set of programs used to enter, edit, format, store and print documents. A document may be anything from a single memo to a complete book. An application package that involves the use of computers to manipulate text data in order to produce office communications in the form of documents. Any of many popular application programs designed for composing, revising, printing, and filing written documents. Word Processing is the efficient and effective production of written communications at the lowest possible cost through the combined use of systems management procedures, automated technology, and accomplished personnel. The equipment used in word processing applications includes but is not limited to the following: dictation and transcription equipment, automatic repetitive typewriters, visual display text editing typewriters, keyboard terminals, etc. b) Give any 2 examples of a word processing package’. [2marks] MS WORD WORD STAR WORD Perfect MS WORKS WORD c) Briefly describe any 5 important features of a word processor. [5 marks] 1) Spelling and grammar checker 2) Import files 3) Mail merge 4) WYSIWYG capability 5) Creation of templates 6) Automatic creation of index and table of contents d) List any 10 facilities that spreadsheets offer. [10 marks] 1. Format cells, rows and columns, specifying for example, the alignment of text, number of decimal points, height and width of a cell. 2. Copy cell contents to other locations 3. Determine the effect of several different hypothetical changes of data 4. Insert, move or delete rows and columns 5. Use functions such as SUM, AVERAGE, MAX, MIN in formulae 6. Create a simple database and sort or query the data to produce a report 7. Write macros to automate common procedures 8. Create templates i.e. spreadsheets with formats and formulae already entered, into which new figures may be inserted. 9. Create multi-dimensional spreadsheets using several sheets, and copy data from one rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 69 sheet to another 10. Create many different types of charts and graphs Shortcomings of spreadsheets While spreadsheets are a great step forward in quantitative modeling, they have deficiencies. At the level of overall user benefits, spreadsheets have four main shortcomings. • Spreadsheets have significant reliability problems. Research studies estimate that roughly 94% of spreadsheets deployed in the field contain errors, and 5.2% of cells in unaudited spreadsheets contain errors. • The practical expressiveness of spreadsheets is limited. Several factors contribute to this limitation. Implementing a complex model requires implementing detailed layouts, cell-at-a- time. Authors have difficulty remembering the meanings of hundreds or thousands of cell addresses that appear in formulas. • Collaboration in authoring spreadsheet formulas is difficult because such collaboration must occur at the level of cells and cell addresses. By comparison, programming
  • 71. COMPUTER OPERATIONS PACKAGES languages aggregate cells with similar meaning into indexed variables with names that indicate meaning. Although some spreadsheets have good collaboration features, authoring at the level of cells and cell formulas remains a significant obstacle to collaboration in authoring spreadsheet models. On the other hand, many people collaborate on entering numerical data and many people can use the same spreadsheet. • Productivity of spreadsheet modelers is reduced by the cell-level focus of spreadsheets. Even conceptually simple changes in spreadsheets (such as changing starting or ending time or time grain, adding new members or a level of hierarchy to a dimension, or changing one conceptual formula that is represented as hundreds of cell formulas) often require large numbers of manual cell-level operations (such as inserting or deleting cells/rows/columns, editing and copying formulas, re-laying out worksheets). Each of these manual corrections increases the risk of introducing further mistakes. These four deficiencies in high-level benefits have deeper causes that, ironically, flow directly from the signature strength of spreadsheets (that they capture the structure of models in terms of WYSIWYG sheet layout for authors and report users). • Spreadsheets capture model logic in terms of sheet layout, especially contiguous layout of cells in a table. Spreadsheets have weak or nonexistent methods to capture higher level structures such as named variables, segmentation dimensions, and time series. • Formulas are subordinated to the cell layout. This forces the sheet layout to carry the structure of the model, not variables and formulas that relate variables. This also causes a large proliferation of cells, formulas and cell-level tasks even when only a few basic concepts are involved in a model. This forces authors to think and work at the level of cells instead of at the level of the natural concepts and structures of the model. • Formulas expressed in terms of cell addresses are hard to keep straight and hard to audit. Research shows that spreadsheet auditors who check numerical results and cell formulas find no more errors than auditors who only check numerical results. • Proliferation of error-prone manual cell-level operations contributes to all four of the high-level problems listed above. Criteria for Selecting Applications Software: • Accuracy - it must be free from errors • Flexibility – it must be able to adapt to changing environment. • Compatibility - it must be compatible with available hardware and software • Recency - it must be current • Cost - it must have reasonable cost • Originality - It must be original • Support - consider continued support from the supplier. • Ease of use - it must be user friendly. • Performance - it must have efficiency in both response time and run time. • Memory requirements Factors to consider when buying application software 1. Cost. This includes the original cost of the package, technical support, and upgrades. 2. Portability, can it be installed on one type of hardware or a variety 3. Relevance of the software to the task at hand. 4. Compatibility with existing hardware software. Will the package run on existing hardware? Can files be easily transferred from existing systems without re-keying? Can files created in the package be exported to other systems in use in the company? 5. It should be on a media compatible with your computer i.e. if you purchase software on CD media your computer should have compact disk drive. 6. Sophistication, simple programs are usually easy to learn, cost less and are appropriate for those who use the software infrequently. 7. Should include enough documentation such as installation instructions, system requirements e.g. Pentium 4, reference manual, registration information, supplier details and user manual. rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 70
  • 72. COMPUTER OPERATIONS PACKAGES 8. Standard software, which is well supported locally i.e. used by most people in that area 9. Is the application upgradeable and does it support future upgrades. 10. Easiness of installation 11. Technical support. Is support available? Is it very costly? Often, technical support contract can add 50% or more to the price of a package, but without it no support at all will be given by the manufacturer. 12. Easy of learning. Are tutorials supplied? Are books on the software available in bookshops? Are training courses available? 13. Easy of use and user- friendliness. Is it easy to use, for example using pull down menus, icons, helpful error messages when you do something wrong? 14. Is the application from a reputable supplier e.g. Microsoft. 15. Do you have enough resourceson your PC to install it e.g. it may require 256MB RAM, 80GB HDD. Memory requirements; software packages vary in the amount of memory they require. Will the system require expenditure on more powerful hardware? 16. Does the version of the product that I am considering run on my personalcomputer system? Is it compatible with my platform (PC, Macintosh, Sun, and so on)? with the processor used in my computer (486, Pentium, Motorola 6040, PowerPC, and so on)? and with the operating system that I am running (DOS, Windows, NeXT Step, UNIX)? 17. Is the product compatible with other programs, such as extensions and device drivers, that I have on my personalcomputer system? 18. Does the product do all that I want it to do? Is it simple enough to use immediately but powerful enough to provide the capabilities that I will want as my familiarity with the program increases? 19. Is the product an up-to-date, current version or release? 20. Does the product have a clear, step-by-step tutorial? Is the product easy to learn? 21. Is the product accompanied by clear, easy-to-follow instructions, or documentation? 22. Does the manufacturer provide technical assistance? Is a toll-free technical assistance number included in the software documentation? Does the manufacturer have a bulletin board or Internet address for technical assistance questions? Does the manufacturer charge for technical assistance? for product revisions or upgrades? 23. Can I find instruction, or training, in the use of the product? 24. Is the product from a respected, well known manufacturer? 25. Does the program have any known problems, or bugs, and will these affect my use of the rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 71 program? 26. Does the product come with a warranty, and what are the conditions of that warranty? 27. Does the product cost more or less than comparable products on the market? Benefits of application software to the user. Installation should be easy, quick and should be provided by the vendor/supplier. Good documentation is usually provided with the application for reference purposes. Onsite assistance from the supplier or vendor Provision of cheaper future upgrades upon acquisition of an application provided you have completed the registration information. Value for money Applications software comes in different 'flavors' - or types: • Utility programs - these can be part of an operating system, but are also available for separate purchase. Examples include virus checkers, disk defragmenters, back up utilities and disk checker software. • Generic - general purpose software that is not written for any particular type of business. Examples of this include word processors and spreadsheets. • Integrated - a collection of software that has a common set of commands/icons. Usually they include word processors, spreadsheets and graphics software, but they can contain databases as well. They tend to be cheaper than purchasing each application separately. • Specific - software written for a defined purpose. Accountancy software is a good example of this, and can be bought by anyone.
  • 73. COMPUTER OPERATIONS PACKAGES • Bespoke - also known as 'tailor made'. A company may need a particular piece of software that it cannot purchase because it does not exist yet - or it does not like what is available. The company can commission the software to be specially written for them. This tends to be expensive. rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 72 SOURCES OF SOFTWARE 1. Freeware o Freeware is the type of freely available software whose developer decides to distribute it for free. In contrast to the open source software, the source code in this case is not available for modifications and further development. Also, it should be noted that the distribution of the software may also be restricted by its developer, often allowing users to download it from his site only. Many free to download applications are available on the Internet. It is always wise to read the license before downloading the software. Many people tend to unknowingly share such applications with other people, without realizing that this may actually be illegal. 2. Shareware o Shareware is very different from these other forms of free software and to some extent also a misnomer. The authors of shareware maintain their full intellectual right over shareware. The only difference between shareware and other commercially available software is that in this case the software is available for freely for trial for a limited number of days, or a limited number of times. After the expiry of the ‘free’ period, the users of shareware are required to pay for it. Source code and collaboration communities which exist around open source projects do not exist in this case. 3. Off-the –shelf/generic or Commercial Software 4. In-house/Custom made/Tailor Made/Bespoke software 5. Outsourcing This involves contracting out software development to a software house - better known as outsourcing, especially where off-the-shelf packages are not available. Advantages o Software houses employ professionals and this may benefit the organisation o Transfer of skills to the existing professionals in an organisation o Organisation can get support from the contractor. Disadvantages o There could be breach of confidentiality. o Contractor may go bankrupt and cease trading leaving the user with no support. o Contractor might not have sufficient experience or understanding of the problem; thus the solution might not be satisfactory. o It takes time for the contractor to understand the user's business and operations, which makes the approach expensive. CLASSIFICATION OF SOFTWARE APPLICATIONS 1. Commercial / generic Packages/Off the shelf software • Commercial software is computer software sold for profit; such software represented, until recently, the vast majority of all software used. • These are bought from a vendor. • Also known as off the shelf packages e.g. MS Office, Pastel. • Also known as work enhancement applications • Generic or Off the shelf software has the advantage of cost effectiveness due to larger market the ability to incorporate available technology in the shortest possible time.
  • 74. COMPUTER OPERATIONS PACKAGES These increase the productivity efficiency in the work place i.e. o Word Processing packages o Spreadsheet packages o Database /Information retrieval Packages o Graphics packages o Data communications Software • Off-the –shelf/generic or Commercial Software This is software that can be purchased, from a software company that develops programs and sells them to many computer users and organizations. Applications such as financial accounting, business graphics and pay roll may be bought. rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 73 Advantages o Cheaper - the software company is able to spread the software development cost over a large number of customers, hence reducing the cost any one customer must pay. o Less risky - the software is in existence, hence you can analyse the features and performance of the package. o The program is a well-tried and tested product with few errors. o Less time - Off-the -shelf software is often installed quickly and easily. o The package is well documented o The packages require little maintenance o There is continued support from the supplier through upgrades. o It is cheaper than custom-written software. The development costs of the package may be millions of pounds, but the customer may be able to buy it for a few hundred pounds, since sales are made to thousands of other customers. o It is immediately available and already thoroughly tested so is unlikely to have major bugs in it o Documentation is usually available in the form of reference manuals, user guides and tutorials o Training courses may be available form third party trainers. o Technical support is usually available from the manufacturers via a Web site or telephone line [at a price]. o Other users of the package can be consulted as to its suitability before purchase. o Upgrades are usually available every year or two Disadvantages o The package may not do exactly what you want it to do; o It may not run on the firm’s existing hardware o It may not interface with other software already in use in the organization. o The organization might need to pay for the features that are not required and never used. o The package may be for general needs and therefore not ideal for the user. o The user has no direct control over the package, 2. Homemade / Customized packages/ Tailor-made Software Customized software is software designed around a company or other organization's processes to make those processes more efficient. It is distinct from market software [commercial or generic], which approaches problems in a general way so that the product can be sold to more than one customer.
  • 75. COMPUTER OPERATIONS PACKAGES Has been written by the vendor specifically for a user’s needs. Also known as in-house packages, tailor-made packages. E.g. most payroll packages, billing software, product design applications Is that application that has been written for a specific user’s needs by a software rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 74 vendor? It is non-standard software. • In-house/Custom made/Tailor Made/Bespoke software This approach requires a development team from within the organisation. The team is usually comprised of programmers and analysts. The team members should be of high calibre, highly trained and reliable. Advantages o Internal professionals understand operations better and therefore can produce an accurate solution. o The Software usually meets user requirements. o Management are in total control of the development process o More flexibility - there is more flexibility in making modifications. o Problem specificity - in-house developed software can give an organisation software programmes that are easily tailored to a unique problem or task. Disadvantages Time and costs of developing the program may be greater than other options In-house staff may lack the expertise needed for the project Reliability of the resultant software is highly questionable. In some cases the developers may attempt to gain fraudulently from the system Disadvantages 1. Being customized, the non-standard software may not be used by any other organization. 2. It has huge support costs after implementation. 3. Dependency syndrome with the supplier. There is heavy reliance on the developers of the software for its continued existence maintenance 4. Future support may be difficult if the supplying company goes under, shuts down, or liquidate or if its development staff leaves. 5. May not be upgradeable and may not run if moved to a new hardware platform. 6. You are tied to a supplier of which you may not be willing to have a maintenance contract with. 7. Written or Custom-built software performs a defined function and is expensive to build. 8. Custom built is expensive to maintain 9. Custom built software has reduced lifespan due to high speed of technological advancement in the field of computers. 3. Managerial applications Help to make management decisions Decision support systems Database Management Systems Report Writing Tools MAKE NOTES ON: How application packages solve problems? Typical problems which can be solved by application packages Customization of packages using macros Utility software Utility software (also known as service program, service routine, tool, or utility routine) is computer software designed to help manage and tune the computer hardware, operating system or application software by performing a single task or a small range of tasks. Some utility software has been integrated into most major operating systems. Examples • Disk storage utilities •
  • 76. COMPUTER OPERATIONS PACKAGES o Disk defragmenters can detect computer files whose contents are broken across several locations on the hard disk, and move the fragments to one location to increase efficiency. o Disk checkers can scan the contents of a hard disk to find files or areas that are corrupted in some way, or were not correctly saved, and eliminate them for a more efficiently operating hard drive. o Disk cleaners can find files that are unnecessary to computer operation, or take up considerable amounts of space. Disk cleaner helps the user to decide what to delete when their hard disk is full. o Disk space analyzers for the visualization of disk space usage by getting the size for each folder (including subfolders) files in folder or drive. showing the distribution of the used space. o Disk partitioners can divide an individual drive into multiple logical drives, each with its own filesystem which can be mounted by the operating system and treated as an individual drive. o Backup utilities can make a copy of all information stored on a disk, and restore either the entire disk (e.g. in an event of disk failure) or selected files (e.g. in an event of accidental deletion). o Disk compression utilities can transparently compress/uncompress the contents of a disk, increasing the capacity of the disk. o File managers provide a convenient method of performing routine data management tasks, such as deleting, renaming, cataloging, uncataloging, moving, copying, merging, generating and modifying data sets. o Archive utilities output a stream or a single file when provided with a directory or a set of files. Archive utilities, unlike archive suites, usually do not include compression or encryption capabilities. Some archive utilities may even have a separate un-archive utility for the reverse operation. • System profilers provide detailed information about the software installed and hardware attached to the computer. • Anti-virus utilities scan for computer viruses. • Text and Hex Editors directly modify the text or data of a file. These files could be data or rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 75 an actual program. • Data compression utilities output a shorter stream or a smaller file when provided with a stream or file. • Cryptographic utilities encrypt and decrypt streams and files. • Launcher applications provide a convenient access point for application software. • Registry cleaners clean and optimize the Windows registry by removing old registry keys that are no longer in use. • Network managers check the computer's network, log events and check data transfer. • Command line interface (CLI) and Graphical user interface (GUI) Allows the user to contact and make changes to the operating system. INTEGRATED SOFTWARE Integrated software is software for personal computers that combines the most commonly used functions of many productivity software programs into one application. The integrated software genre has been largely overshadowed by fully functional office suites, most notably Microsoft Office, but at one time was considered the killer application type responsible for the rise and dominance of the IBM PC in the desktop business computing world. In the early days of the PC before GUIs became common, user interfaces were text-only and were operated mostly by function key and modifier key sequences. Every program used a different set of keystrokes, making it difficult for a user to master more than one or two programs. Programs were loaded from floppy disk, making it very slow and inconvenient to switch between programs and difficult or impossible to exchange data between them (to transfer the results from a spreadsheet to a word processor document for example). In response to these limitations, vendors created multifunction integrated
  • 77. COMPUTER OPERATIONS PACKAGES packages, eliminating the need to switch between programs and presenting the user with a more consistent interface. The potential for greater ease-of-use made integrated software attractive to home markets as well as business, and packages such as the original AppleWorks for the Apple II and Jane for the Commodore 128 were developed in the 1980s to run on most popular home computers of the day. Context MBA was an early example of the genre, and featured spreadsheet, database, chart-making, word processing and terminal emulation functions. However, because it was written in Pascal for portability, it ran slowly on the relatively underpowered systems of the day. Lotus 1-2-3, which followed it, had fewer functions but was written in assembler, providing it with a speed advantage that allowed it to become the predominant business application for personal computers.[2] The integrated software market of today is exemplified by entry-level programs such as Microsoft Works which are often bundled with personal computers as starter productivity suites. SOFTWARE SUITES/BUNDLED SOFTWARE • A software suite or application suite is a collection of computer programs, usually application software and programming software of related functionality, often sharing a more-or-less common user interface and some ability to smoothly exchange data with each other. • Sometimes software makers introduce suites that are little more than repackaged versions of older programs offered at a lower price. • The solution might be software suites or bundled software. A suite is a collection of the full-featured versions of each software application - word processing, spreadsheet, database management, graphics, communications and sometimes organizers. • These applications are from the same software manufacturer and are packaged together in a large box and sold at prices that are much lower than if they were purchased individually - usually less than half of the original collective price! The software applications contained in a suite or bundle are the same applications a professional user might purchase individually. No corners have been cut, and additional features may have been added such as a common interface that allows any of the programs to be accessed from the same main menu, a consistent screen layout used by each of the programs, and the ability to easily exchange data from one program to another. INTEGRATED SOFTWARE/BUNDLED SOFTWARE / SOFTWARE SUITE SOFTWARE that contains several applications rolled into one.Integrated software usually includes word processing, spreadsheet, database, graphics and communication capabilities. Two popular Integrated softwarepackages are Microsoft Works and ClarisWorks: In integrated software, you will be able to work on a spreadsheet to perform calculations, store addresses and phone numbers in a database and be able to link information from the spreadsheet the database when you work with the word processor in the integrated package. Object Linking Embedding [OLE] is a standard that, Allows applications to be linked rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 76 together. OLE-DB allows applications to import virtually any form of data into the database. Definitions of integrated software on the Web: • A group of applications designed to work together and share data easily. Software that combines the features of several different applications in a single program (e.g. word processing, database, spreadsheet, graphics, and communications).. Advantages of integrated applications Easy to use Generally costs much less
  • 78. COMPUTER OPERATIONS PACKAGES Require or needs less RAM Ability to pass data from one module to another. Takes up much less hard disk space Better organization of information. Data is stored in the database, calculations in an electronic spreadsheet images in a graphical application package The advantages of bundled software suites are • Low cost compared to buying each application separately • Option to install all of the programs at the same time or only the programs you want to use • Consistent interface from one application to another • The ability to share information between applications • Future upgrades can update each application all at the same time • Ideal for personal use, professional use, large or small business • Each application is the full-featured version rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 77 The disadvantages are • High initial cost • All applications are from the same manufacturer - you might prefer a word processor from one company, a spreadsheet from a different manufacturer, etc. • May be purchasing more software than you actually need • Installation of the entire suite of applications takes up a large amount of storage space on your internal hard disk • Several large manuals to study if you plan to master each application, or the package might not include printed manuals in order to keep the cost low Disadvantages Limited portability. The same applications must exist on every computer that you wish to open the document. Offer fewer features and less versatility than stand alone versions or software. Functional limitation. Its rigid you cannot change it to suit your specific needs. EXAMPLES OF INTEGRATED SOFTWARE • Microsoft Office 97 • Microsoft Works • Claris Works • Lotus SmartSuite 97 • Microsoft Office 2003,2007,2010 2013 OPEN SOURCE SOFTWARE • Open source is a type of software which is freely available and its source code is available for further development, modification. Generally all open source software have a community of developers who provide support, documentation and even binary versions of the software to people who may be interested in it. These additional services, though, may not be free monetarily. • There are several ongoing open source software projects. The open source nature of these projects means that there will be several people working on modifying and improving the software from around the world. Some such examples include the Web browser Mozilla Firefox, content management software like Drupal, Joomla etc. SOFTWARE COPYRIGHT The Copyright, Designs and Patents Act
  • 79. COMPUTER OPERATIONS PACKAGES Copyright is a legal concept, giving the creator of an original work exclusive rights to control its distribution for a certain time period. Copying computer software is therefore a breach of copyright and a criminal offence. The Act covers stealing software, using illegally copied software and manuals, and running purchased software on more machines than the license allows. The legal penalties for breaking the copyright law include unlimited fines and up to two years in prison. All the software that you use should be fully licensed. When you purchase software you usually are licensed to use it on just one computer. It is illegal to make copies of the software to use on other computers, even if they are your own. rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 78 Software licences can be: • Single user - licensed for installation on one computer • Multi-user - the license allows you to install the software on a named number of computers • Site-licence - the licence lets you install the software onto an unlimited number of computers, as long as they are on one distinct site such as a school Software protection Software companies try to prevent illegal copying of their disks using the following methods: • Copy protection - the disk (or CD-Rom) may be formatted in a special way so it cannot easily be copied. • Restricting the number of installations - each installation is recorded on an installation disk and only a certain number are allowed. • A registration key - a unique series of letters and numbers that is asked for when running the program. The software will not run if the registration key is not typed in correctly and online multiplayer games will not to run if another user is online who has used the same key. • A phone or Internet activation code - this requires the user to call a number or go online to register the product. They then receive a unique computer-specific serial number. • Encryption - data can be scrambled up and cannot be read without the correct software. • A Dongle - a piece of hardware that must be plugged into the computer to run the software. Each one contains a unique electronic serial number and as they are expensive to produce they are mostly used to protect high-end software packages. • Details of the user are built into the software - when the software is run it displays the original users name. This does not prevent the copying but it makes is obvious that the copy is illegal. • A Keyfile - a small file with a unique code that is placed in the same directory as the program. If the code is not valid then the software will not run. SOFTWARE PIRACY Unauthorized copying of software. unauthorized use or reproduction of copyrighted patented material. unauthorized copying of software The production of illegal copies of software. By far, the biggest legal problem affecting the computer industry today is software piracy, which is the illegal copying or use of programs. Piracy is a huge problem mainly because it is so easy to do. In most cases, it is no more difficult to steal a program than it is to tape a music CD that you have borrowed from a friend. Software pirates give up the right to
  • 80. COMPUTER OPERATIONS PACKAGES receive upgrades and technical support, but they gain the use of the program without paying for it. Implications of Software piracy Loss of business to software companies. Lack of technical support, no connection with supplier upgrades. Software incompatibility, may require a key, which you might not have, as a result you can’t install it. Virus Spread Lawsuits for copyright, which may be very costly in terms of reputation and money. Piracy harms all software publishers, Regardless of their size. Software publishers spend years developing software for the public to use. A portion of every dollar spent in purchasing original software is channeled back into research and development so that better, more advanced software products can be produced. When you purchase pirated software, your money goes directly into the pockets of software pirates instead. Software piracy also harms the local and national economies. Fewer legitimate software sales result in lost tax revenue and decreased employment. Software piracy greatly hinders the development of local software communities. If software publishers cannot sell their products in the legitimate market, they have no incentive to continue developing programs. Many software publishers simply won’t enter markets where the piracy rates are too high, because they will not be able to recover their development costs. Software piracy harms everyone in the software community including you, the end user. How? 1) Piracy results in higher prices for duly licensed users, 2) Piracy reduces levels of support, and 3) Delays in the funding and development of new products, causing the overall selection and quality of software to suffer. THE DIFFERENT TYPES OF SOFTWARE PIRACY There are five basic forms of software piracy, and all are damaging both to the software publisher and to you, the end user. The five basic types of piracy are: • Soft lifting. This form of piracy occurs when extra copies of a program are made within an organization for employees to use. It also includes Disk swapping among friends and associates. • Hard-Disk Loading. Some computer dealers load unauthorized copies of software onto the hard disks of the computers they offer for sale, as an incentive for an end user to purchase a computer from that particular dealer. • Counterfeiting. This is the illegal duplication and sale of copyrighted software, often in a form designed to make the product appear legitimate. Software counterfeiting can be very sophisticated, including significant efforts to replicate packaging, logos, and anti-counterfeiting techniques such as holograms. It can also be unsophisticated, consisting of inferior or hand-written labels, with disks folded into a plastic bag and sold on street corners. A recent trend in counterfeiting is the emergence of compilation CD-ROMs, where numerous unauthorized software publishers’ programs appear on one CD-ROM. In any form, software counterfeiting is very damaging to both the software developer and legitimate end users. • Online. This form of piracy occurs when copyrighted software is downloaded to users connected through a modem to an electronic bulletin board or the Internet without the express permission of the copyright owner. This should not be confused with sharing public domain software or providing “shareware.” Shareware is software that may or may not be copyrighted but is generally offered for little or no charge by the author for nearly unrestricted use, including copying or sharing with others. Microsoft distributes promotional products, free software, updates, or enhancements over bulletin boards or online services, which may or may not be licensed for use solely with licensed Microsoft products. You should check the EULA accompanying the product to determine how it can be used. • License Misuse. This form of piracy occurs when copyrighted software is distributed outside the restricted legitimate channels it was designed for or the product is used in ways not allowed in the license agreement. Examples of license misuse include: rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 79
  • 81. COMPUTER OPERATIONS PACKAGES (1) Academic product misuse This form of license misuse occurs when a product that is manufactured, licensed, and specifically marked for distribution to educational institutions and students at reduced prices is diverted into normal commercial channels of distribution. Typically this product will contain a sticker indicating that it is academic product and for use only by educational institutions. (2) Not for Resale (NFR) product misuse. Again, this form of license misuse occurs when a product that has been clearly marked Not for Resale, and is typically distributed as a promotional or sample product and is not licensed for normal commercial distribution and use, is diverted into normal commercial channels of distribution. (3) Original equipment manufacturer (OEM) stand-alone product. This form of license misuse occurs when OEM version software has been unbundled from its designated computer system and distributed as a separate, “stand-alone” product. Microsoft’s agreement with computer manufacturers prohibits them from distributing Microsoft products in this fashion, i.e. without accompanying computer hardware. Microsoft products on the retail shelf should never include a line on the front cover of the User’s Guide that states, “For Distribution Only With New Computer Hardware.” (3) “Microsoft Easy Fulfillment” (MEF) product misuse. This form of license misuse occurs when a “Microsoft Easy Fulfillment” (MEF) product is diverted into normal commercial channels of distribution. The MEF product may be distributed only to end users who have a Select or Open (MOLP) license and who order the product in accordance with their license terms. The MEF product has a sticker on the jewel case identifying the product as “Microsoft Easy Fulfillment.” (4) Volume licensing misuse. Volume Licensing enables organizations to acquire the rights to copy and use specific Microsoft software products with agreements tailored to the number of products needed at the particular organization. These volume programs offer a broad range of products and licensing options and reduce administrative overhead and software management costs. Microsoft offers two types of volume license: a. Select provides savings for medium and large organizations with significant volume requirements through forecasting software needs over a two-year period. b. Open provides savings for small and medium organizations for licenses of as few as 20 units of a particular software product, with a simple ordering process. Misuse under volume licensing occurs when organization copies software purchased through the volume program on more computers than specified in their license agreement. Other violations occur when an organization allows concurrent use of software products (which currently is offered only as an option under the Select and Open programs) without the purchase of the option that allows for this concurrent use. User licenses show users rights to use pieces of software. INTRODUCTION TO DATABASE SYSTEMS A DATABASE is a shared and integrated collection of logically related records or files consolidated into a common pool that provides data for one or more uses. Is a collection of files? An organized collection of interrelated files. Is a collection of related files that provides a way of finding information quickly and easily from a chosen reference point? Is an integrated collection of logically related records or files? A database consolidates records previously stored in separate files into a common pool of data records that provides data for many applications. Examples of databases are MS Access, MS Works Database, and DBaseIV, Oracle, SQL rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 80
  • 82. COMPUTER OPERATIONS PACKAGES Building Blocks of a Database System BIT BYTE FIELD RECORD FILE DATABASE • A byte is also known as a character • A field is also known as a word • A file is also called a table or relation File-Is a collection of related records. Record-Is a collection of fields. It is a collection of fields arranged in a predefined rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 81 order. Field-Is a collection of single items. It is an implementation of the data attribute. It is the smallest unit of data to be stored in a database. Primary key-Is a field whose value identifies one only one record in a file. Secondary key-An alternative index for identifying an entity. Its value can identify single entity occurrences of all entity occurrences. A subset of all entity occurrences. Foreign key-Are pointers or links to occurrences of a different file. A foreign key in one file must be a primary key in another file. Descriptors-Are any other fields that describe business entities. Traditional/Conventional/Flat Filing Systems • This is programming with files. Each user defines and implements the files needed for a specific application so that each application has its own separate data files and software programs • Although both users will be interested in the same data, each maintains separate files and programs to manipulate these files and this results in data redundancy and a lot other problems associated with it. Advantages of the Database Approach • Control over data redundancy • Increased data consistency/Reduced data confusion • Increased data integrity – concerned with validity and accuracy of data • Reduction in wastage of storage space • Program/Data independence • Increased productivity of application development • Improved data security • Data sharing Disadvantages • Database systems are complex, difficult and time consuming to design • There is greater impact of failure • Extensive conversion costs involved • Initial training is required for all users • Concurrence problems - where more than one user access and attempt to update the same record at the same time - there is file edit locking to prevent this. • Ownership problems - sometimes some individuals tend to own the data and thus refuse access by other individuals or departments in the organisation. • Resources problem - with database extra resources are needed e.g. more workstations and other devices. Substantial hardware and software startup costs are involved Security problems - there is increased exposure to unauthorised entry into the data. However, this could be reduced by the use of regularly changed passwords and by physically denying access to unauthorised users.
  • 83. COMPUTER OPERATIONS PACKAGES rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 82 DATABASE TERMINOLOGY • Entity - a real world object or event or anything that is capable of independence existence and about which we can collect information e.g. person, building, transaction, election • Attribute – a characteristic or property of an entity e.g. name • Primary key – an attribute that uniquely identifies an entity or record. A field that uniquely identifies a record in a table. In a students table, for instance, a key built from last name + first name might not give you a unique identifier (two or more Jane Does in the school, for example). To uniquely identify each student, you might add a special Student ID field to be used as the primary key. • Foreign key - A key used in one table to represent the value of a primary key in a related table. While primary keys must contain unique values, foreign keys may have duplicates. For instance, if we use student ID as the primary key in a Students table (each student has a unique ID), we could use student ID as a foreign key in a Courses table: as each student may do more than one course, the student ID field in the Courses table (often shortened to Courses.student ID) will hold duplicate values. • Normalization - The process of structuring data to minimise duplication and inconsistencies. The process usually involves breaking down a single table into two or more tables and defining relationships between those tables. The process of breaking up a table into multiple tables, each of which has a single theme, thereby reducing data redundancy; 2) The technique that reduces or eliminates the possibility that a database is subject to modification anomalies • Query - A view of your data showing information from one or more tables. For example, you could query a Students database asking Show me the first and last names of the students who take both history and geography and have Alice Hernandez as their advisor. Such a query displays information from the Students table (firstname, lastname), Courses table (course description) and Advisor table (advisor name), using the keys (student ID, course ID, advisor ID) to find matching information. Literally, a question you ask about data in the database in the form of a command, written in a query language, defining sort order and selection, that is used to generate an ad hoc list of records; 2) The output subset of data produced in response to a query. • SQL - Structured Query Language (pronounced sequel or ess-queue-ell). A computer language designed to organize and simplify the process of getting information out of a database in a usable form, and also used to reorganize data within databases. • Relation - A single store of related information. A table consists of records, and each record is made up of a number of fields. You can think of the phone book as a table: It contains a record for each telephone subscriber, and each subscriber’s details are contained in three fields – name, address and telephone. • DBMS - Database management system. A program which lets you manage information in databases. Microsoft Access is a DBMS, although the term is often shortened to ‘database’. So, the same term is used to apply to the program you use to organize your data and the actual data structure you create with that program. • Domain - A collection or range of all the possible values a field can contain. Although a field’s domain is typically finite, it may be infinite as well. • Derived attribute - Synonymous with computed attribute, for which the value is calculated from those contained in other fields. Usually, computed fields’ values are calculated from other fields’ values that occur in the same record • Metadata - Data about data and the data’s structure within a database. Technical metadata reflects the description of the structure, content, keys, and indexes of data and their source of origin, while business metadata reflects definitions about measures (facts) using calculations • OLAP - (Online Analytical Processing)The OLAP Council defines online analytical processing as, A category of software technology that enables analysis, managers and executives to gain insight into data through fast, consistent, interactive access to wide variety of possible views of information that have been transformed from raw data to reflect the real dimensionality of the enterprise as understood by the user.
  • 84. COMPUTER OPERATIONS PACKAGES • Record - Synonymous with row and tuple. An instance of data in a table, a record is a collection of all the facts related to one physical or conceptual entity; often referring to a single object or person, usually represented as a row of data in a table, and sometimes referred to as a tuple in some, particularly older, database management systems. • Schema - The database’s metadata -- the structure of an entire database, which specifies, among other things, the tables, their fields, and their domains. In some database systems, the linking or join fields are also specified as part of the schema 2) The description of a single table. Also called a Logical Schema. • Concatenated key – a key formed by joining two or more attributes • Relationship a link or association between any two entities in a database • ERD - An entity-relationship (ER) diagram is a specialized graphic that illustrates the interrelationships between entities in a database. ER diagrams often use symbols to represent three different types of information. Boxes are commonly used to represent entities. Diamonds are normally used to represent relationships and ovals are used to represent attributes. TYPES OF DATABASE RELATIONSHIPS One-to-One o Exactly one record in one table is related by a common linking field to exactly one record in another table, implying that each value of the linking field appears no more than once in each of the tables. Both tables can have only one record on either side of the relationship. Each primary key value relates to only one (or no) record in the related table. They're like spouses—you may or may not be married, but if you are, both you and your spouse have only one spouse. Most one-to-one relationships are forced by business rules and don't flow naturally from the data. In the absence of such a rule, you can usually combine both tables into one table without breaking any normalization rules. rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 83 One-to-Many o Exactly one record in one table is related by a common linking field to one or more records in another table, implying that each value of the linking field is unique in the first table, but not necessarily so in the second. The primary key table contains only one record that relates to none, one, or many records in the related table. This relationship is similar to the one between you and a parent. You have only one mother, but your mother may have several children. Many-to-Many • One or more records in one table may be related to one or more records in a second table by a common value or linking (join) field. This implies that each value of the linking field may appear any number of times in either or both tables. Each record in both tables can relate to any number of records (or no records) in the other table. For instance, if you have several siblings, so do your siblings (have many siblings). Many-to-many relationships require a third table, known as an associate or linking table, because relational systems can't directly accommodate the relationship. The Database Administrator This is a person responsible for planning, designing and maintaining the organisation's database. This person relates to the management, system analysts, programmers and other stakeholders in the organisation. He needs to have adequate managerial and technical abilities to suit the job. He therefore must have a sound knowledge of the structure of the database and the DBMS. Responsibilities of the Database Administrator (DBA) • Ensures that the database meets the needs of the organisation. • Ensures facilities for the recovery of data • Ensures the functioning of report generation systems form the DBMS • The DBA is also responsible for the documentation of the DBMS through the designing and availing of the data dictionary and manuals for the users giving such direction as the
  • 85. COMPUTER OPERATIONS PACKAGES general use of the database, access to information, deletion of records from the system and the general validation and verification of data. • The design of the database • After the initial design, the DBA must monitor the performance of the database, and if problems surface (such as a particular report taking an unacceptably long time to produce), appropriate changes must be made to the database structure. • Keeping users informed of changes in the database structure that will affect them; for example, if the size or format of a particular field is altered or additional fields added • Maintenance of the data dictionary for the database, and responsibility for establishing conventions for naming tables, columns, indexes so on. • Implementing access privileges for all users of the database; that is, specifying which items can be accessed and / or changed by each user. • Allocating passwords to each user. • Providing training to users in how to access and use the database. • Manage the organizations • -data resources • -database plans • -design • -operations • -training • -user support • -security Maintenance • Maintain data consistency and security • Approve access to data stored • Approve access procedures • ABILITY to delete, add, modify –existing data must be tightly controlled. Database Management System (DBMS) The DBMS is an application program that provides an interface between the operating system and the user in order to make access to the data as simple as possible. It has several other functions as well, and these are described below. 1. Data storage, retrieval and update. The DBMS must allow users to store retrieve and update information as easily as possible, without having to be aware of the internal structure of the database. 2. Creation and maintenance of the data dictionary 3. Managing the facilities for sharing the database. The DBMS has to ensure that problems do not arise when two people simultaneously access a record and try to update it 4. Back up and recovery. The DBMS must provide the ability to recover the database in the rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 84 event of system failure. 5. Security. The DBMS must handle password allocation and checking, and the ‘view’ of the database that a given user is allowed. The data dictionary The data dictionary is a ‘database about the database’. A data dictionary, as defined in the IBM Dictionary of Computing, is a centralized repository of information about data such as meaning, relationships to other data, origin, usage, and format.[1] The term may have one of several closely related meanings pertaining to databases and database management systems (DBMS): • a document describing a database or collection of databases • an integral component of a DBMS that is required to determine its structure • a piece of middleware that extends or supplants the native data dictionary of a DBMS It will contain information such as: 1. What tables and columns are included in the present structure? 2. The names of the current tables and columns 3. The characteristics of each item of data, such as its length and data type; 4. Any restrictions on the value of certain columns
  • 86. COMPUTER OPERATIONS PACKAGES 5. The meaning of any data fields that are not self-evident; for example, a field such as rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 85 ‘course type’; 6. The relationships between items of data 7. Which programs access which items of data, and whether they merely read the data or change it? Advantages and any disadvantages of databases # ADVANTAGES # DISADVANTAGES 1 Supports data sharing 1 Limitations of databases arise from increased technological complexity 2 Ensures increased data security 2 Developing a large database and installing a DBMS can be difficult and expensive. 3 Ensures data independence 3 More hardware capability is required, since storage requirements for the organization of data, overhead control data, and the DBMS is greater 4 Data integrity is guaranteed. The functions in the DBMS can be used to enforce the integrity rules with minimum programming in the application programs. 4 Problems of data inconsistency can arise if a distributed database approach is used. 5 Reduces or minimizes data redundancy 5 Longer processing times may result from high volume transaction processing applications since extra layer software [the DBMS] exists between application programs and the Operating system. 6 Consistence of data is ensured 6 Security and integrity of data are major concerns. 7 Support data integration. Since related data is stored in one single database, enforcing data integrity is much easier Centralized databases are vulnerable to errors, fraud and failures. 8 Related data can be shared across programs since the data is stored in a centralized manner 9 Enforcing of standards in the organization and structure of data files is required and also easy in a Database System, since it is one single set of programs, which is always interacting with data files 10 The application programmer need not build the functions for handling issues like concurrent access, security, data integrity, etc. The programmer only needs to implement the application business rules. This brings in application development ease. Q* Limitations of file Processing Systems that the DBM system address i. Data duplication - Same kind of information is stored in several files ii. Lack of Data integration – Independent files make it difficult to provide end users with info for ad-hoc requests that require accessing data stored in different files iii. Data dependence – In a file processing system, the organization of files, their physical location on storage hardware and application software used to access those files depend on each other. Changes in format and structure o data and records in file require changes to all the programs Q* what is a DBMS (Data base Management System) Is a collection of software programs that: i. Stores data , in a uniform and consistent way ii. Organizes the data, into records in a uniform and consistent way iii. Allows access to the data, in a uniform and consistent way
  • 87. COMPUTER OPERATIONS PACKAGES A collection of software programs that stores organizes and allows access to the data in a uniform and consistent way Is a collection of programs that enables users to create and maintain a rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 86 database? A general purpose software system that facilitates the process of defining constructing and manipulating databases for various applications. Database Environment i. Database ii. Database users iii. DBM System iv. Data Dictionary v. Database Administrator vi. User/system interface Database Users i. Casual users ii. Naïve users – parametric users iii. Sophisticated end users I. Occasionally use it, and if they do a HLL such as AQL may be used. II. Those who use Standard queries and updates only e.g. bank cashiers, data entry clerks’ e.t.c. III. Know the whole range of facilities on a database environment. Q a. Explain the 3 Major disadvantages of a file system (6) b. Give and explain any 7 functions of a DBMSystem FUNCTIONS OF A Database Management SYSTEM 1. Storage, Retrieval Update 2. Catalogue 3. Logical transactions 4. Concurrency control 5. Recovery 6. Security 7. Communications 8. Integrity 9. Data Independence 10. Utilities 1. Storage, Retrieval Update - Allows users with the ability to store, retrieve and update data in the database. 2. Catalogue - Allows a catalogue in which descriptions of data items are stored and which is accessible to users 3. Logical Transactions - Allows a mechanism which will ensure that either all of the updates corresponding to a given transaction are made or not made. .e.g. ABORT – ROLLBACK or undo all the changes COMMIT- Transaction gone thru and is already in the database. 4. Concurrency Control - Allows a mechanism to ensure that the database is updated correctly when multiple users are updating the database concurrently LOCKING OR DEADLOCK situations must be avoided 5. Recovery - Allows a mechanism for recovering the database in the event that the database is damaged in any way.
  • 88. COMPUTER OPERATIONS PACKAGES - A before / after image is usually created rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 87 6. Security - Allows a mechanism to ensure that only authorized users can access the database. - Authorizations, encryption features and limited views can be used as security provisions 7. Communication - Must be capable of integrating with communications software on the database environment on a multi-user environment. 8. Integrity - Allows a mechanism to ensure that both the data in the database and changes to the data follow certain rules. 9. Data Independence - (Has facilities to) support the independence of programs from the actual structure of the database. 10. Utilities - Provide a set of utility services e.g. optimized COMPONENTS OF A DBMS 1. Data dictionary/directory 2. Data language 3. Application development tools 4. Security software 5. Report writers 6. Query language 7. Web server software 8. Teleprocessing monitors 9. Archiving, backup and Recovery systems 1. DATA DICTIONARY/ DIRECTORY • Contains the names and descriptions of every data element in the database. • Also contains descriptions of how data elements relate to one another. • Ensures that data is stored in a uniform and consistent manner hence reducing redundancy. 2. DATA LANGUAGES • Data description language (DDL) describes the characteristics of data elements. • DDL requires the application program to use standardized commands to retrieve and process data from a database. • Data manipulation language (DML) consists of commands such as FIND, GET, INSERT 3. APPLICATION DEVELOPMENT TOOLS • A program designed to help programmers develop application programs that use the database e.g. CASE TOOLS 4. SECURITY SOFTWARE • Provides a variety of tools to shield database from unauthorized access and from viruses 5. REPORT WRITERS • Allows programmers, mgrs and others to design out put reports. 6. QUERY LANGUAGE • A set of commands used primarily for accessing data from a database. • You can ask ad-hoc questions of the database interactively without the aid of programmers. • Examples SQL, NLQ, QBE. Structured Query language, Natural language Queries and Query by Example. 7. WEB SERVER SOFTWARE • Turns the computer system housing database into a web server and enables users with web connection to access data from wherever they are located. • Also convert data into a format that is readable by standard browsers.
  • 89. COMPUTER OPERATIONS PACKAGES rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 88 8. TELEPROCCESSING MONITORS • A software package that manages communication between the database and remote terminals. 9. ARCHIVING, BACK UP AND RECOVERY SYSTEMS • Provides the database manager with tools to make copies of the database. • Restart/ Recovery systems are tools used to restart the database and to recover lost data in the event of a failure. OBJECTIVES AND BENEFITS OF DATABASE APPROACH 1. Data redundancy is reduced –reduces the duplication of data. 2. Data inconsistence avoided. 3. Sharing of data is promoted –since data is stored in centralized. 4. Standards are enforced, thru the data dictionary /catalogue 5. Base of application development /maintenance is available 6. Uniform security/ privacy /integrity control s are applicable to group of users 7. SECURITY – Passwords, access controls PRIVACY - Authorized users INTEGRITY – Accurate data 8. Integration of data is achieved - since data is stored in one db 9. Data independence is achieved/ observed - it is the immunity of applications to changes in storage structure and access strategy. 10. Data accessibility and responsiveness. 11. Structured Query Language e.g. select name from customer where town = Harare” RISK TO DATABASE APPROACH 1. New, specialized personal 2. Backup – important DBMS function (Recovery) 3. Shared data – conflict and concurrency control 4. Technological complexity 5. Expensive to develop a large database and installing a DBMS can be difficult. 6. More hardware capability is required – storage requirements overhead control data and the DBMS required more memory 7. Problems of inconsistence can arise if a distributed data approach is used. 8. Longer processing time may result from high volume transaction processing applications. 9. Security and integrity are major concerns. 10. Centralized database are vulnerable to errors fraud and failures. DATABASE MODELS OR TYPES OF DATABASES i) Hierarchical database model ii) Network database model iii) Relational database model iv) Object-oriented database model Hierarchical Database Model • It resembles an inverted tree structure, organogram or family tree. It reflects one-to-one (1:1) or one-to-many (1:M) relationships only among the records. • The uppermost record is called the root and from there data are organized into groups containing parent and child records(nodes) • A parent record is allowed to have one or more child records but a child node can have only one parent • Because relationships between data items follow clearly defined paths, access to data is fast • There is no relationship between brother or sister nodes • Each record is related to others in a parent-child relationship or tree structure.
  • 90. COMPUTER OPERATIONS PACKAGES • Relationships between among records form a hierarchy or tree structure. • The relationship among records is one to many since each data element is related only to DEPT rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 89 one element above it. • Searching a record involves moving progressively downward from a root and along the branches of the tree until the desired record is located. Diagram Network Database Model • Is almost similar to the hierarchical model but is more flexible and versatile because a record can be linked to any other record in the model; i.e. the network model can reflect a many-to-many (M:N) relationship. • The route to data is not necessarily downwards but can in any direction • The major advantage is its ability to handle sophisticated relationships among various records and more than one path can lead to desired data level • Network complexity limits users in their ability to access the database without the help of programming staff • A record can belong to a number of parents • Relationship among records is many to many • Allows entry into a database at multiple points because any data element or record can be related to many other data elements. • Permits a record to be a member of more than one set at a time Hierarchical and network models are less flexible than other database models because the relationship between records must be determined and implemented before a search can be conducted. Diagram Student Course
  • 91. COMPUTER OPERATIONS PACKAGES rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 90 Relational Database Model • Data elements are viewed as being stored in the form of tables(relations) • There are no pointers or links to talk about but the data is organized into two dimensional tables which are known as relations • Each table is composed of unique rows or records which are also known as tuples and each cell in the relation must be single valued • Relationships are either 1:1 or 1:M and in the case where M:N relationships exist junction tables are created All data elements within the database are viewed as being stored in the form of tables • Database Packages based on this structure link records in different or various tables to provide information to users as long as the share common data elements. • Data is organized in 2-dimensional tables. Diagram CUSTOMER CUSTOMER NO. CUSTOMER NAME CUSTOMER ADDRESS - - - - - - Object Oriented Model • Each object is bound together with its own data and a set of instructions that describe the behaviour and attributes of the object • The objects use messages to interact with one another e.g. the object building in a database can have the attributes: type, size, colour etc • This model uses objects and messages to accommodate new types of data and provide for advanced data handling Each object in an object-oriented database model is bound together with its own data and a set of instructions that describe the behavior and attributes of the objects. Objects use messages to interact with one another. Every object is described by a set of attributes. E.g. the object building in a database or architectural drawing may have the attributes TYPE, SIZE, COLOUR just as in any. Every object must have a set of procedures or routines or a set of methods. E.G methods for an architectural drawing might include instructions to display, rotate, or explode the drawing on a screen. FILE CONCEPTS The purpose of a computer file is to hold data required for providing information. A computer file is a collection of related records. Records consist of fields and the fields are made up of characters. A character is the smallest element of a file. A character may be a letter of the alphabet, a digit or of a special form (symbols). Logical files show what data items are contained and what processing may be done while physical files are viewed in terms of how data is stored on storage media. Types of Files a) Master Files They hold permanent data for use in applications such as stock control and credit control. Usually much of the data items in these files do not change frequently or with each transaction, e.g. name, address or date of birth. b) Transaction files
  • 92. COMPUTER OPERATIONS PACKAGES These are also called movement files. They hold temporary records of values. They are used to update the master file and are overwritten after the updating of the master file. Examples of Transaction files: • A customer order file or records, each of which has data on a particular order. • A time sheet data file that contains records, each of which has data on the number of hours worked by a particular employee. • A stock transaction file that contains records of stock additions or removals – one record for each movement. rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 91 c) Look up files They are reference files from which such information as prices list and mailing list can be obtained. d) Archive files These are files that are used to store information that has not been in use in the recent past and would not be in use in the near future – so are used to store historical data. e) Backup files These are copies of transaction files and master files held for security purposes f) Transition files Derived from a transaction file by the addition or deletion or ammendment of data. It is produced as a temporary file during data processing often by the addition of master file information to a transaction file prior to updating or output. Examples of transition files: • An employee time sheet transaction file which has had employee names added (from an employee master file) and re-sorted into department order • A customer order transaction file to which the price of each item ordered has been taken from a (computerised) catalogue and added FILE PROCESSING Is the process of updating the records in a file to accurately reflect changes in the data? It can be a manual process where procedures are in place to update forms, which are sent to the respective person responsible for the update. It can also be a computerized process where information is first stored in transaction files until the master file is updated. File processing methods: 1. BATCH PROCESSING is execution of a series of programs (jobs) on a computer without manual intervention. Batch jobs are set up so they can be run to completion without manual intervention, so all input data is preselected through scripts or command-line parameters. This is in contrast to online or interactive programs which prompt the user for such input. A program takes a set of data files as input, process the data, and produces a set of output data files. This operating environment is termed as batch processing because the input data are collected into batches on files and are processed in batches by the program. Batch Processing Transactions are collected and processed in batches [groups]. Transaction processing in which transactions are gathered and stored for later execution. E.g. a supermarket chain operates 5 outlets. At the end of the day all information on sales [transaction file] is collected, the main records [master file] are updated with the sales for that day. Performs a group of tasks all at once, while requiring little [or no] interaction with the user.
  • 93. COMPUTER OPERATIONS PACKAGES It is a great time saver because the computer can perform repetitive functions quickly consistently. Benefits Batch processing has these benefits: • It allows sharing of computer resources among many users and programs, • It shifts the time of job processing to when the computing resources are less busy, • It avoids idling the computing resources with minute-by-minute mannual intervention and rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 92 supervision, • By keeping high overall rate of utilization, it better amortizes the cost of a computer, especially an expensive one. COMMON BATCH PROCESSING USAGE • Data processing • A typical batch processing procedure is End of day-reporting (EOD), especially on mainframes. Historically systems were designed to have a batch window where online subsystems were turned off and system capacity was used to run jobs common to all data (accounts, users or customers) on a system. In a bank, for example, EOD jobs include interest calculation, generation of reports and data sets to other systems, print (statements) and payement processing. • Printing • A popular computerized batch processing procedure is printing. This normally involves the operator selecting the documents they need printed and indicating to the batch printing software when, where they should be output and priority of the print job. Then the job is sent to the print queue from where printing daemon sends them to the printer. • Databases • Batch processing is also used for efficient bulk database updates and automated transaction processing, as contrasted to interactive online transaction processing (OLTP) applications. • Images • Batch processing is often used to perform various operations with digital images. There exist computer programs like Batch Image Processor that let one resize, convert, watermark, or otherwise edit image files. • Converting • Batch processing is also used for converting a number of computer files from one format to another. This is to make files portable and versatile especially for proprietary and legacy files where viewers are not easy to come by. • Job scheduling • UNIX utilizes cron and at facilities to allow for scheduling of complex job scripts. Windows has a job scheduler. Most high-performance computingclusters use batch processing to maximize cluster usage. 2. REAL-TIME PROCESSING, A real-time operating system (RTOS) OR REAL-TIME PROCESSING is a multitaskingoperating system intended for real-time applications. Such applications include embedded systems (programmable thermostats, household appliance controllers), industrial robots, spacecraft, industrial control (see SCADA), and scientific research equipment. A RTOS facilitates the creation of a real-time system, but does not guarantee the final result will be real-time; this requires correct development of the software. An RTOS does not necessarily have high throughput; rather, an RTOS provides facilities which, if used properly, guarantee deadlines can be met generally or deterministically (known as soft or hard real-time, respectively). An RTOS will typically use specialized scheduling algorithms in order to provide the real-time developer with the tools necessary to produce deterministic behavior in the final system. An RTOS is valued more for how quickly and/or predictably it can respond to a particular event than for the amount of work it can perform over a given period of time. Key factors in an RTOS are therefore a minimal interrupt latency and a minimal thread switching latency.
  • 94. COMPUTER OPERATIONS PACKAGES An early example of a large-scale real-time operating system was Transaction Processing Facility developed by American Airlines and IBM for the Sabre Airline Reservations System. Real-time Processing The master records are updated as and when the transactions occur. A form of transaction processing in which each transaction is executed as soon as complete data becomes available for the transaction. A supermarket chain would be linked by a network to a main computer. Each time a sale is made the stock information is updated and the sale information is also updated. It is expensive and complicated. Record and file locks are implemented to avoid problems with real-time processing. 3. ONLINE PROCESSING, or OLP, refers to a class of systems that facilitate and manage transaction-oriented applications, typically for data entry and retrieval transaction processing. The term is somewhat ambiguous; some understand a transaction in the context of computer or database transactions, while others (such as the Transaction Processing Performance Council) define it in terms of business or commercial transactions. OLP has also been used to refer to processing in which the system responds immediately to user requests. An automatic teller machine (ATM) for a bank is an example of a commercial transaction processing application. The technology is used in a number of industries, including banking, airlines, mailorder, supermarkets, and manufacturing. Applications include electronic banking, order processing, employee time clock systems, e-commerce, and eTrading. The most widely used OLP system is probably IBM'sCICS. Online processing A general term for when one computer is interacting directly and simultaneously with another computer. Many sources of information are available online. Available for immediate use. The master file is updated with the transactions through some form of communication link. All real-time processing involves online processing. Not all online processing needs to be real-time. Require interaction of the user. Benefits Online Processing has two key benefits: simplicity and efficiency. Reduced paper trails and the faster, more accurate forecasts for revenues and expenses are both examples of how OLP makes things simpler for businesses. Disadvantages As with any information processing system, security and reliability are considerations. Online transaction systems are generally more susceptible to direct attack and abuse than their offline counterparts. When organizations choose to rely on OLP, operations can be severely impacted if the transaction system or database is unavailable due to data corruption, systems failure, or network availability issues. Additionally, like many modern online information technology solutions, some systems require offline maintenance which further affects the cost-benefit analysis. Centralized processing An information system where all critical data and programs are stored on one main computer, usually a mainframe. Unlike the task-sharing concept of a client/server system, the central computer retains all the brains and brawn. A computing environment in which all processing takes place on a mainframe or central computer. Puts all processing and control authority within one computer to which all other computing devices respond. rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 93
  • 95. COMPUTER OPERATIONS PACKAGES Distributed Processing The ability to have several computers working together in a network, where each processor runs different activities for a user, as required. Computers connected together by a communications network. Data processing occurs on each of the computers, unlike a centralized processing system in which terminals are connected to a host computer that performs all of the data processing. Use of computers at various locations, typically interconnected via communication links for the purpose of data access and/or transfer. A computer system in which processing is performed by several separate computers linked by a communications network. The term often refers to any computer system supported by a network, but more properly refers to a system in which each computer is chosen to handle a specific workload, and the network supports the system as a whole. Offline processing When your computer performs an operation when it is not connected to any other computers, it is working offline. Means that your computer is not currently connected to an Internet rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 94 server. Not connected (to a network). Not available to the network Time sharing A way of sharing out computer facilities between a number of people who want to use the computer at the same time. Each has a separate terminal and gets the impression that they have sole use of the computer with their own 'account'. Similar to NETWORKING. Transaction processing o A type of computer processing in which the computer responds immediately to User requests, with each User interaction considered to be a transaction. Automatic teller machines for banks are probably the best-known example. o In computer science, transaction processing is information processing that is divided into individual, indivisible operations, called transactions. Each transaction must succeed or fail as a complete unit; it cannot remain in an intermediate state. Master file is the main information source in any type of organization. File processing is the update of the master file [actual records] through manual or computerized methods.
  • 96. COMPUTER OPERATIONS PACKAGES FILE ORGANIZATION METHODS ACCESS File Organization-Is the arrangement of data records on storage media It determines the manner in which individual records can be accessed or rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 95 retrieved Definitions of cycle time on the Web: • The time usually expressed in seconds for a controller to complete one on/off cycle. Definitions of access time on the Web: • The average time interval between a storage peripheral (usually a disk drive or semiconductor memory) receiving a request to read or write a certain location and returning the value read or completing the write. The amount of time it takes a computer to locate an area of memory for data storage or retrieval. • The time required to retrieve data from a storage device and transmit it to a specified location. Definitions of random access on the Web: • Storage systems where data may be stored and accessed in any order, independent of the ordinal position of the data when it was originally recorded. This is the opposite of linear (3) access, or linear recording media such as magnetic tape, which necessarily preserves the sequential relation of the data as it is recorded, and depends on this sequential relation for accurate playback. See non-linear recording. • Able to read any location directly; without having to read sequentially to the location. Definitions of sequential access on the Web: • Data must be read in the order it appears. This method applies to tape, and to a lesser degree to disks. Reading data from a file whose records are organized on the basis of their successive physical positions. To reach a specific record, all records previous to that record must be read, in order. Magnetic computer tapes are sequential access storage device. • Refers to reading or writing data records in sequential order, that is, one record after the other. To read record 10, for example, you would first need to read records 1 through 9. This differs from random access, in which you can read and write records in any order. TYPES OF QUERIES i. DIRECT QUERY ii. INVERTED QUERY i. DIRECT QUERY • Is one where the user can identify the entity in which he is interested? • He may want to know some of the particular of attributes of that entity. • e.g. Where a sales man wants to know the amount and location of a particular product in the organization. • He is able to identify the product by name or product number and this identification is used as the key for making the query which is also the primary record key. • The basic purpose of the direct query is to know the attribute values of already identified entities ii. INVERTED ENTITIES
  • 97. COMPUTER OPERATIONS PACKAGES • is one where the user does not know the identification of entities in which he is interested • he wants to identify the entities by some criteria or attribute values • e.g. the purchase department requiring a list of items for wh9ch the stock level is below the rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 96 desired level • in this case user does not know the identity of items already but want to know it • only specify a criterion as the basis of the query • Obviously the primary key cannot be used for retrieval, it is not available • Some attribute like stock level has to be used for the retrieval of records MODELS OF FILE ORGANISATION i. serial file organization ii. sequential file organization iii. indexed sequential file organization iv. direct file organization v. inverted file organization i. SERIAL FILE ORGANISATION • Is one where records are not stored in any particular order • They are stored in the order in which they are received • New records are added at the end of the files • This method of file organization is used when - the usage of the records is not clearly known - as a means of recording transaction as they happen - as dump files reflecting the physical layout of a file - as a prelude to organizing the file in another order i.e. transactions may be punched and stored on a serial file, the file may be subsequently be stored into a desired sequence - gives maximum utilization of space - no room is left for inserting other records - does not cater for direct access to records - used on magnetic tapes - popular on output files, archive files, security files i. SEQUENTIAL FILE ORGANISATION - records are arranged in a pre-determined sequence determined by the primary key - appropriate for files which are store on tape or disk - nor generally used for online system that demand fast response - mainly used for batch processing applications - suitable when there is for little file enquiry - can be used for variable length records as well as fixed length records - waste space as some space is left of reserved for other records to be inserted in order to preserve the order or organization UPDATING Updating on tape is carried out in batch mode by reading the whole file and rewriting it after necessary modification on to a new file. On disk can be carried out without rewriting the whole file. RETRIEVAL Retrieval of a record from a sequential file on tape media can be made only in the sequential mode by reading all the records in sequence till the desired record is reached. Retrieval of a record from a sequential file on direct access media (DISK) can be made by using sequential reach skip search, binary search. HIT RATE
  • 98. COMPUTER OPERATIONS PACKAGES In a batch processing run: The proportion of the number of records processed during a run to the total number of records on the file is called a hit rate. The higher the volatility and the lower the frequency of updating,, the higher the rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 97 hit rate. PROCESSING OF SEQUENTIAL FILES Tapes provides for only serial access Disks can be accessed in a serial order or random order. iii) INDEXED SEQUENTIAL FILES • Records are stored in sequence but in addition an index is provided to enable individual records to be located directly after reading the index. • Records are pointed to by indexes. • Used with disks only not with magnetic tapes. • Wastes space. • The index may be ignored and the data is read sequentially • The file may be accessed sequentially but using the index to skip over unwanted records =selective sequential access • Index may be read into memory and used to obtain data randomly. • Records can be accessed sequentially OR randomly. iv) DIRECT FILE ORGANISATION Files are stored or haphazardly and an address key is used as reference. Records are physically located at an address that is calculated from its primary key field. The calculation of the address from the key field is called hashing. Records are scattered on the storage disk instead of being arranged next to one another or linked via a pointer field. Records can rapidly be retrieved and accessed directly Used on magnetic disks (e.g. floppies, hard disk) and optical disks. Costly in terms of device used and space. v) INVERTED FILE ORGANISATION special case of indexed sequential organization an index is maintained for every attribute in the record the main file itself may not be stored if direct queries are not to be handled the entire file data is, in any case, stored in the indexes Useful for handling inverted queries. vi) MULTI-RING FILE ORGANISATION useful for handling inverted query when sets of records have same attribute value Each set of records with same attribute values is linked into a ring. A ring of records is a chain where the last in the chain points to the first. One of the records is anchored to the index so that it provides an entry point into the ring. The index of the attribute is read first to retrieve records with a particular attribute value. All records with that attribute value can be located. COMPUTER MEMORY RAM (Random Access Memory) Also referred to as Main Memory, Primary Memory or Working Memory is memory that is accessed by the CPU as it processes information. The CPU also places results of processing on the memory chip. The memory has the following characteristics. 1) can be read from 2) can be changed and can be rewritten 3) used for short-term storage of data i.e. it is temporary storage,
  • 99. COMPUTER OPERATIONS PACKAGES 4) is volatile (data lost when power is turned off). rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 98 Types of RAM • DRAM (Dynamic RAM) This is the most common type of computer memory. DRAM needs refreshing and is refreshed hundreds of times each second in order to retain data. During recharging it cannot be accessed by the CPS • SRAM (Static RAM) SRAM is approximately 5 times faster (and twice as expensive, as DRAM). It does not have to be constantly refreshed. Because of its lower cost and smaller size, DRAM is preferred for the main memory, while SRAM is used primarily for cache memory. • SDRAM (synchronous dynamic RAM) is the standard memory offering in the PC industry and is faster than DRAM because it's synchronized to the system clock. . It is designed for mainstream home and business applications, email, and basic audio and video streaming. It provides single-channel memory and is available on our mainstream and value desktop system. • DDR SDRAM (double data rate synchronous dynamic RAM) takes all the features of ordinary SDRAM and increases the frequency bandwidth to improve system performance and speed. • RDRAM (Rambus dynamic RAM) is able to load a new stream of data before the previous stream has completed, resulting in faster access speeds. The RDRAM memory features dual-channel processing which doubles data throughput to further enhance performance. This type of memory is optimized for high-end multimedia tasks involving video and audio. Dual Channel RDRAM is shipped on our performance desktop systems powered by Pentium 4 processors • VRAM: Memory designed for storing the image to be displayed. • CACHE RAM is a small block of high-speed memory located between the Processor and main memory and is used to store frequently requested data and instructions. When the processor requests data, it will check in the cache first The computer has two types of memory chips within the system unit, known as RAM and ROM. ROM (Read Only Memory) This memory chip has essential programs that start up the computer hardwired on the microchip during the manufacture of the computer. It forms what is known as FIRMWARE, being a halfway between hardware and software. The characteristics of this memory are that:- 1) can be read from, 2) cannot be changed 3) is permanent 4) non-volatile (data not lost when power is turned off). ROM Stores instructions data which do not change It is written once during manufacture It is for holding software such as MS-DOS.Windows 95, 98.XP. It is programmed by the manufacturer and cannot be altered by the user It is static non volatile It stores control routines for personal computers VARIATIONS OF ROM Allow users to store and in some cases to change data stored in ROM PROM [Programmable ROM] is not programmed during manufacture but can be programmed by the user. It is programmed according to the needs of the user organization. If you make a mistake the ROM once programmed will became permanent to the effect that any errors will never be corrected thus the user will throw away any chip if errors are made.
  • 100. COMPUTER OPERATIONS PACKAGES EPROM [Erasable Programmable ROM] can be programmed and erased as many times. This time you don’t have to worry about errors too much because there is room for correction. The programming is done electronically. Stored data can be lost by exposing it to Ultra Violet light over a period of minutes. 1) EEPROM [Electrically Erasable Programmable ROM] can be read, erased, rewritten, without removing from the computer. The erasing rewriting process is very slow compared with reading, which limits their use. These can be erased programmed with electrical pulses. Can be erased in a few Milliseconds rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 99 MEMORY CAPACITY Everything entering into the computer is converted into digital (number) form, and is stored in that form. When one needs to view the information, it is converted into human sensible text, graphics, audio or video by the operating system. A binary digit is known as a bit being either a ‘0’(zero) or a ‘1’(one). It is the smallest item that can be stored in a computer’s memory. Memory capacity is measured in bytes, a byte being a set of eight(8) bits and the byte often represents a single character. Measurement units used for computer memory are:- o BIT 1 binary digit (Either a 0 or a 1) o BYTE Eight bits. o NIBBLE Half byte/4 bits o KILOBYTE (KB) 1024 bytes o MEGABYTE (MB) Million bytes o GIGABYTE (GB) Billion bytes o TERABYTE Trillion bytes NETWORKS A computer network, often simply referred to as a network, is a collection of computers and other hardware components interconnected by communication channels that allow sharing of resources and information Where at least one process in one device is able to send/receive data to/from at least one process residing in a remote device, then the two devices are said to be in a network. Simply, more than one computer interconnected through a communication medium for information interchange is called a computer network. Networks may be classified according to a wide variety of characteristics, such as the medium used to transport the data, communications protocol used, scale, topology, and organizational scope. Communications protocols define the rules and data formats for exchanging information in a computer network, and provide the basis for network programming. Well-known communications protocols include Ethernet, a hardware and link layer standard that is ubiquitous in local area networks, and the Internet protocol suite, which defines a set of protocols for internetworking, i.e. for data communication between multiple networks, as well as host-to-host data transfer, and application-specific data transmission formats. Computer networking is sometimes considered a sub-discipline of electrical engineering, telecommunications, computer science, information technology or computer engineering, since it relies upon the theoretical and practical application of these disciplines. Properties Computer networks: 1. Facilitate communications Using a network, people can communicate efficiently and easily via email, instant messaging, chat rooms, telephone, video telephone calls, and video conferencing. 2. Permit sharing of files, data, and other types of information
  • 101. COMPUTER OPERATIONS PACKAGES In a network environment, authorized users may access data and information stored on other computers on the network. The capability of providing access to data and information on shared storage devices is an important feature of many networks. 3. Share network and computing resources In a networked environment, each computer on a network may access and use resources provided by devices on the network, such as printing a document on a shared network printer. Distributed computing uses computing resources across a network to accomplish tasks. rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 100 4. May be insecure A computer network may be used by computer hackers to deploy computer viruses or computer worms on devices connected to the network, or to prevent these devices from normally accessing the network (denial of service). 5. May interfere with other technologies Power line communication strongly disturbs certain forms of radio communication, e.g., amateur radio. It may also interfere with last mile access technologies such as ADSL and VDSL. 6. May be difficult to set up A complex computer network may be difficult to set up. It may also be very costly to set up an effective computer network in a large organization or company. NETWORK TOPOLOGIES A network topology is the arrangement of elements (such as data links or nodes) in a network. It is the physical arrangement of terminals in a local area network. The choice of topology is dependent upon • type and number of equipment being used • planned applications and rate of data transfers • required response times • cost Definitions of hub on the Web: A common connection point for devices in a network. Hubs are commonly used to connect segments of a LAN. A hub contains multiple ports. When a packet arrives at one port, it is copied to the other ports so that all segments of the LAN can see all packets. A passive hub serves simply as a conduit for the data, enabling it to go from one device (or segment) to another. ... Node – a terminal point in a communications network. Workstation – A computer terminal or micro- or minicomputer system designed to support the work of one person. MESH TOPOLOGY Mesh topology work on the concept of routes. In Mesh topology, message sent to the destination can take any possible shortest, easiest route to reach its destination. In the previous topologies star and bus, messages are usually broadcasted to every computer, especially in bus topology. Similarly in the Ring topology message can travel in only one direction i.e clockwise or anticlockwise. Internet employs the Mesh topology and the message finds its route for its destination. Router works in find the routes for the messages and in reaching them to their destinations. The topology in which every devices connects to every other device is called a full Mesh topology unlike in the partial mesh in which every device is indirectly connected to the other devices.
  • 102. COMPUTER OPERATIONS PACKAGES rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 101 STAR TOPOLOGY Is a network in which nodes are connected to a central component as its hub? The central component can be a switching device like a switch or PABX [private automatic branch exchange], a computer [minicomputer to which workstations or PCs are connected] or just a wiring center that is a common termination point for the nodes, called a hub. A HUB is a component that serves as a common termination point for multiple nodes and that can relay [store forward] signals along the appropriate paths. Definitions of star network on the Web: • A network in which all terminals are connected through a single point, such as a star coupler. • A network topology in the form of a star. At the center of the star is a wiring hub or concentrator, and the nodes or workstations are arranged around the central point representing the points of the star. Advantages of star topology It is easy to add or remove nodes Because each node has its own link to the central node, the star is more reliable than other topologies. Full utilization of resources i.e. printer, sharing of processor Direct connection of terminals to the main processor, means that if one terminal breaks down it wont affect other terminals. Disadvantages of star topology
  • 103. COMPUTER OPERATIONS PACKAGES All traffic between two nodes passes through the central node. If the central component breaks down, the whole network is down. The number of ports of the central component limits the number of connected nodes. A star topology requires a lot of cabling since all data path connections must be to the central node. There is no direct communication between or among workstations Sharing of processor delays in the processing of jobs. BUS/LINEAR TOPOLOGY Describes a network in which each n This is also sometimes called a horizontal, multidrop or multi point network. Though it is preferable to use the last terms for connections with a mainframe/mini computer as in the following diagram. In a bus messages nodes but every node can hear each message as it goes past. When the signal/message reaches an end of the bus, a terminator absorbs it, to keep it from traveling back again along the bus line, other messages already in the line. The data/signals/messages are transmitted in packets along the bus. Each packet is send with a receiver identification code destination and all computers on the network ar messages coming to them. Definitions of bus network on the Web: • A single-cable LAN, in which all computers on the network are connected in series to a single cable. On a bus network, each computer hears all of the transmi the line, and selects only those that are addressed to its location. This is the simplest and most common LAN technology. Advantages of Bus Network/topology When a node breaks down, the network does not break down. A bus uses relatively Direct communication due to direct connection. Fast processing since there is no Host computer Once a cable has been laid down any new equipment can easily be connected to the network by a simple tapping into the c Disadvantages of Bus Network/topology In a bus topology it is not always easy to add a node. [E.g. installation of extra tap in thick Ethernet]. Diagnosis/trouble shooting can be difficult. Expensive to run [several processors] Communication between components of the network traveling in opposite direction along the bus can collide rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm s node is connected to a common line. travel in both directions and do not go through the individual to avoid interference with that is an address of are permanently on the alert for any transmissions going down less cables compared to other topologies cable. – Detectors. tion causing loss of transmitted information. 102 ode e ssions able.
  • 104. COMPUTER OPERATIONS PACKAGES Because of this collision a detection system has to be present to control the re of lost information thereby making it a more expensive option RING NETWORK eby A ring network has nodes connected in a circular way. Each node has two neighboring nodes Data flow is unidirectional. A message is forwarded in one direction until it reaches the destination with intermediate nodes acting as relay [store forward] units. The destination node copies the message and passes the message again to the ring. This message then continues to circulate around the ring back to the source. Definitions of ring network on the Web: • A network topology in the form of a closed loop or circle. Each node in the network is connected to the next, and messages move in one direction around the system. When a message arrives at a node, the node examines the address information in the mess the address matches the node's address, the message is accepted; otherwise the node regenerates the signal and places the message back on the network for the next node in the system. ... Advantages of ring network The message return provides the The node removes its own message from the ring. Little cabling needed compared to Star. Each node acts as relay unit. Packet collisions do not occur because information is traveling in one direction. Relatively cheap Efficient and accurate means of communication. There is no dependency on the host computer or file server as each node controls transmission to and from itself. Disadvantages of ring network Adding or removing nodes disrupts the network. If one of the nodes breaks down, the whole network will be down. If the network cable breaks the whole network is affected rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm source with a form of acknowledgement. to install. 103 re-transmission message. If
  • 105. COMPUTER OPERATIONS PACKAGES rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 104 TREE TOPOLOGY Tree topologies are comprised of the multiple star topologies on a bus. Tree topologies integrate multiple star topologies together onto a bus. Only the hub devices can connect directly with the tree bus and each Hub functions as a root of a tree of the network devices. This bus/star/hybrid combination supports future expandability of the computer networks, much better than a bus or star. Advantages of a Tree Topology • Point-to-point wiring for individual segments. • Supported by several hardware and software venders. Disadvantages of a Tree Topology • Overall length of each segment is limited by the type of cabling used. • If the backbone line breaks, the entire segment goes down. • More difficult to configure and wire than other topologies. LANs and WANs There are two types of network: LAN and WAN. LAN (LOCAL AREA NETWORK) A LAN is a high-speed data network that covers a relatively small geographic area. It typically connects workstations, personal computers, printers, servers, and other devices. LANs offer
  • 106. COMPUTER OPERATIONS PACKAGES computer users many advantages, including shared access to devices and ap exchange between connected users, and communication between users via electronic mail and other applications. The development of standard networking protocols and media has resulted in worldwide proliferation of LANs throughout business an Typically connects computer in a single building or campus. Developed in 1970s. Medium : optical fibres, Low latency (except in high traffic periods). High speed networks (0.2 to 100 Mb/sec). Speeds adequate for most distr Problems : Multimedia based applications Typically buses or rings. Ethernet, Token Ring A LAN is a Local Area Network covering a small area such as one building e.g. in a school or a college. WAN (WIDE AREA NETWORK) A network consisting of computers of LAN's connected across a distance WAN can cover small to large distances, using different topologies such as telephone lines, fiber optic cabling, satellite transmissions and microwave transmissions geographic areas. Dedicated transoceanic cabling or satellite uplinks may be used to connect this type of network. Using a WAN, schools in Harare can communicate with places like Pretoria in a matter of minutes, without paying enormous phone bills. A WAN is complicated. It uses multiplexers to connect local and metropolitan networks to global communications networks like the Internet. To users, however, a WAN will not appear to be much different than a LAN or a MAN. Developed in 1960s. Generally covers large distances (states, countries, continents). Medium: communication circuits connected by Routers forwards packets from one to another following a route from the sender to the receiver. Store-and-Forward Hosts are typically connected (or close to) the routers. Typical latencies : 100ms Problems with delays if using Typical speed: 20 - 2000 Kbits/s. Not (yet) suitable for distributed computing. New standards are changing the landscape. A WAN is a Wide Area Network coverin rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm applications, file and educational organizations. , coaxial cables, twisted pair, wireless. distributed systems transmissions. Wide Area Networks (WANs) connect larger ithout routers. - 500ms. satellites. covering a large geographical area. 105 plications, .
  • 107. COMPUTER OPERATIONS PACKAGES Advantages and disadvantages of networks ADVANTAGES OF GROUP WORKING SHARING RESOURCES OVER A NETWORK. ADVANTAGES OF INSTALLING A NETWORK 1. Speed. Networks provide a very rapid method for sharing and transferring files. Without a network, copying them to floppy disks, then carrying or sending the disks from one computer to another shares files. This method of transferring files (referred to as sneaker-net) is very time-consuming. 2. Cost. Networkable versions of many popular software programs are available at considerable savings when compared to buying individually licensed copies. Besides monetary savings, sharing a program on a network allows for easier upgrading of the program. The changes have to be done only once, on the file server, instead of on all the individual workstations. Low cost. Single device shared by several machines reduce the need to buy many peripheral devices. Resource sharing also serves money. An installation can have several low-cost work stations accessing a single file-server. That puts a lot of processing power on the user’s desk without the expense of large mainframe systems. 3. Security. Files and programs on a network can be designated as copy inhibit, so that you do not have to worry about illegal copying of programs. Also, passwords can be established for specific directories to restrict access to authorized users. Security is good - users cannot see other users' files unlike on stand-alone machines. 4. Centralized Software Management. One of the greatest benefits of installing a network at a school is the fact that all of the software can be loaded on one computer (the file server). This eliminates that need to spend time and energy installing updates and tracking files on independent computers throughout the building. Site licenses are likely to be cheaper than buying several stand-alone licenses. 5. Resource Sharing. Sharing resources is another area in which a network exceeds stand-alone computers. Some organizations cannot afford enough laser printers, fax machines, modems, scanners, and CD-ROM players for each computer. However, if these or similar peripherals are added to a network, they can be shared by many users. Resource sharing is the primary benefit of networking. It allows users on different machines to share modems, printers, tape drives and disk space, for example, users can send network messages requesting to use a central printer, allowing everyone to share that resource. Users realize the benefit of sharing information. Data files can be shared between machines on the network, allowing users to see invoices, results of surveys, company newsletters, and other information. 6. Electronic Mail. The presence of a network provides the hardware necessary to install an e-mail system. E-mail aids in personal and professional communication for all school personnel, and it facilitates the dissemination of general information to the entire school staff. Electronic mail on a LAN can enable students to communicate with teachers and peers at their own school. If the LAN is connected to the Internet, students can communicate with others throughout the world. 7. Flexible Access. Networks allow data information access from any computer in the rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 106 campus. 8. Workgroup Computing. Workgroup software (such as Microsoft BackOffice) allows many users to work on a document or project concurrently. For example, educators located at various schools within a county could simultaneously contribute their ideas about new curriculum standards to the same document and spreadsheets. 9. It turns isolated computers into integrated systems, providing an environment where resources are shared and capacity problems reduced.
  • 108. COMPUTER OPERATIONS PACKAGES 10. It allows growth. If more computing resources become a need, a new computer can be installed, added to the network, and immediately accessed by other machines and users. 11. High reliability. If applications share data, the data can be replicated across several machines. If one machine goes down, another can take its place and provide the data to the applications. 12. A file server is easy to back up as all the data is stored in one place rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 107 DISADVANTAGES Disadvantages of Installing a Network 1. Expensive to Install. Although a network will generally save money over time, the initial costs of installation can be prohibitive. Cables, network cards, and software are expensive, and the installation may require the services of a technician. Purchasing the network cabling and file servers can be expensive. 2. Requires Administrative Time. Proper maintenance of a network requires considerable time and expertise. Many organizations have installed a network, only to find that they did not budget for the necessary administrative support. Increased administration. There will be need for a systems administrator to tune the network, monitor the network, administer database files, and ensure network integrity (ensure the network runs smoothly) 3. File Server May Fail. Although a file server is no more susceptible to failure than any other computer, when the files server goes down, the entire network may come to a halt. When this happens, the entire school may lose access to necessary programs and files. 4. Cables May Break. Some of the configurations are designed to minimize the inconvenience of a broken cable; with other configurations, one broken cable can stop the entire network. 5. Security concerns. Some user can gain unauthorized access to private data. There is a danger of hacking, particularly with wide area networks. Security procedures are needed to prevent such abuse. Of all the disadvantages, the greatest drawback is security concerns; therefore, network security is a priority in the development of network applications. 6. Network failure. As applications increase their use of a network, network failures become catastrophic. 7. Virus attack. A networked system is vulnerable to destructive network messages. For example, a message that sparks damaging activity (like erasing files) may enter the system via the network.Viruses can spread to other computers throughout a computer network. 8. Managing a large network is complicated, requires training and a network manager usually needs to be employed. 9. If the file server breaks down the files on the file server become inaccessible. E-mail might still work if it is on a separate server. The computers can still be used as stand alones. Network Security The field of network security in general and of TCP/IP security in particular is too wide to be dealt with we take the most common security exposures and measures to counteract them. Because many, if not all, security solutions are based on cryptographic algorithms. Security Issues This section gives an overview of some of the most common attacks on computer security, and it presents viable solutions to those exposures and lists actual implementations.
  • 109. COMPUTER OPERATIONS PACKAGES Common Attacks For thousands of years, people have been guarding the gates to where they store their treasures and assets. Failure to do so usually resulted in being robbed, neglected by society or even killed. Though things are usually not as dramatic anymore, they can still become very bad. Modern day I/T managers have realized that it is equally important to protect their communications networks against intruders and saboteurs from both inside and outside. We do not have to be overly paranoid to find some good reasons why this is the case: Tapping the wire: to get access to clear text data and passwords Impersonation: to get unauthorized access to data or to create unauthorized e-mails, rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 108 orders, etc. Denial-of-service: to render network resources non-functional Replay of messages: to get access to and change information in transit Guessing of passwords: to get access to information and services that would normally be denied. Guessing of keys: to get access to encrypted data and passwords (brute-force attack, chosen cipher text attack, chosen plaintext attack) Viruses, Trojan horses and logic bombs: to destroy data Though these attacks are not exclusively specific to TCP/IP networks, they should be considered potential threats to anyone who is going to base his/her network on TCP/IP, which is what the majority of enterprises, organizations and small businesses around the world are doing today. Hackers (more precisely, crackers) do likewise and hence find easy prey. Observing the Basics Before even thinking about implementing advanced security techniques such as the ones mentioned in the following sections, you should make sure that basic security rules are in place: Passwords: Make sure that passwords are enforced to be of a minimum length (typically six to eight characters), to contain at least one numeric character, to be different from the user ID to which they belong, and to be changed at least once every two months. User IDs: Make sure that every user has a password and that users are locked out after several logon attempts with wrong passwords (typically five attempts). Keep the passwords to superuser accounts (root, supervisor, administrator,etc.) among a very limited circle of trusted system, network and security administrators. System defaults: Make sure that default user IDs are either disabled or have passwords that adhere to the minimum requirements stated above. Likewise, make sure that only those services are enabled that are required for a system to fulfill its designated role. Physical access: Make sure that access to the locations where your systems and users physically reside is controlled appropriately. Information security begins at the receptionist, not at the corporate firewall. Help desk: Make sure that callers are properly identified by help desk representatives or system administrators before they give out forgotten passwords or user IDs. Social engineering is often the first step to attack a computer network. Solutions to Security Issues Therefore, a combination of several such solutions should be considered in order to guarantee a certain level of safety and security. Encryption: to protect data and passwords Authentication and authorization: to prevent improper access Integrity checking and message authentication codes (MACs): to protect against the improper alteration of messages
  • 110. COMPUTER OPERATIONS PACKAGES Non-repudiation: to make sure that an action cannot be denied by the person who rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 109 performed it Digital signatures and certificates: to ascertain a party's identity One-time passwords and two-way random number handshakes: to mutually authenticate parties of a conversation Frequent key refresh, strong keys and prevention of deriving future keys: to protect against breaking of keys (crypto-analysis) Address concealment: to protect against denial-of-service attacks Content inspection: to check application-level data for malicious content before delivering it into the secure network What is the Internet? The Internet is the network of networks being a worldwide collection of computers that communicate with one another over cables, satellites and optical fibers. It is literally the whole hardware mass. The Internet is the network used to transport information. Internet, by definition is a network of networks that interact with each other through exchange of data packets. The Internet hosts an enormous information base and carries numerous information resources and services.. When we refer to the Internet we are usually talking about the World Wide Web (WWW) which is the most used feature of the Internet. The WWW stores millions of web pages on web servers. These pages can contain text, pictures, movies, animation and sound. Web pages are written in a language or code called HTML (Hypertext Markup Language). A set of web pages is called a website. Each web page has its own unique address or URL. The URL will have the format http and a domain (such as .co.uk). What goes in between is arbitrary, but often has the term www such as in http://www.name.co.uk. but it doesn’t have to (e.g. http://news.bbc.co.uk). Most sites have a page that links the user to the other main areas of the site. This is called the homepage. Web pages are connected by hypertext links. When a link is clicked you will be taken to another page which could be on another server in any part of the world. When you move around web pages you are said to be surfing the net. For this you need a program to read the pages (called a browser), such as Firefox or Internet Explorer. To search for a particular item or topic on the net you use a search engine. There are many different kinds of search engine, each using slightly different ways of searching and indexing web content. Google, MSN and Alta Vista are all examples of search engines, while Yahoo and Excite are web directories (a bit like the Yellow Pages phone book) which have a search function built in. The World Wide Web Is software that runs on the internet which includes all documentation that is shared and accessed on the internet. A Web page is a document designed to be accessed and read over the WWW. It must have an address in a recognized format. DEFINITION OF TERMS ISPs (Internet Service Providers) • An ISP is a company that provides access to the Internet to individuals or companies. ISPs provide local dial-up access from your personal computer to their computer network and their network connects you to the Internet. • An institution (usually a private company) that provides access to the Internet in some form, usually for money. • A business that delivers access to the Internet.
  • 111. COMPUTER OPERATIONS PACKAGES • Are the companies who provide you with access to the internet. Commonly used ISPs in rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 110 Zimbabwe are: 1. PowerTel 2. ZOL 3. Africom 4. Ecoweb 5. Telecel 6. Comone 7. BSAT 8. Brodacom 9. Mweb Most offer the same basic package of Internet access, email addresses, web space for your own pages and local rate call charges. Browser or web browser • A web browser is a software application that enables a user to display and interact with HTML documents hosted by web servers or held in a file system. Popular browsers available for personal computers include Microsoft Internet Explorer, Mozilla Firefox, Opera, and Safari. A browser is the most commonly used kind of user agent. The largest networked collection of linked documents is known as the World Wide Web. • Is a program that allows you to view the pages on the Web? The most widely used are 1. Internet Explorer 2. Mozilla Firefox 3. Google chrome 4. Opera 5. Safari All browsers will have a number of similar features to help you use the Web: • Forward and back buttons to move between pages • A history folder which stores details of recently visited web pages • A stop button if a page is taking too long to load • Favorites and bookmark options to store often visited pages • Options to cut, copy, save and print the information viewed Search engines • Internet search engines help users find web pages on a given subject. The search engines maintain databases of web sites and use programs (often referred to as spiders or robots) to collect information, which is then indexed by the search engine. Similar services are provided by directories, which maintain ordered lists of websites, eg Yahoo! • Examples of search engines are: Google, MSN, Bing, Yahoo, AltaVista Internet address • The numbering system used in TCP/IP internetwork communications to specify a particular network or a particular host on that network with which to communicate. Internet addresses are commonly denoted in dotted decimal form. Examples of internet addresses 1. www.facebook.com 2. www.google.com 3. www.yahoo.com 4. www.gmail.com 5. www.herald.co.zw • An IP address (Internet Protocol address) is a unique number, a kind of telephone number, used by machines (usually computers) to refer to each other when sending information through the Internet. This allows machines passing the information onwards on behalf of the sender to know where to send it next, and for the machine receiving the information to know that it is the intended destination. List of Internet Terminology ARPANET: The acronym stands for Advanced Research Projects Agency Network. ARPA of the United States Department of Defense developed ARPANET, which became the world's first packet switching network. Internet is the successor of ARPANET.
  • 112. COMPUTER OPERATIONS PACKAGES Internet Service Provider: A company, which provides users with an access to the Internet, is known as an Internet service provider or Internet access provider. ISP, as it is called, offers email accounts and other services like remote storage of files for its customers. OSI Model: The Open System Interconnection Model is used to describe a layered communication and network protocol design of a network. It is composed of seven layers, each of which performs certain functions and provides the layers above it with some services. Go through an elaborate description of the OSI model. Internet Protocol Suite: It is a set of communication protocols, which are used for the Internet. Transmission Control Protocol (TCP) and Internet Protocol (IP) were the two pioneering protocols to be introduced in the Internet protocol standard. The Internet protocol suite is composed of a set of layers wherein; each layer provides a service to the upper layers in the set. The upper layers deal with abstract data while the lower layer protocols translate data into physically transmittable forms. PPP: Point-to-Point protocol (PPP) is a data link protocol that facilitates the establishment of a direct connection between two nodes on a network. Here is a brief introduction to the Point-to-Point-protocol. IP Address: It is a way of numerically identifying an entity on a computer network. The original addressing system known as IPv4, used 32 bit addresses. With the growth of the Internet, IPv6 came to be used wherein the addresses are composed of 128 bits. You might want to know how to find your IP address. MAC Address: Media Access Control address (MAC) is the physical hexadecimal address assigned to each device on a network. Domain Name System: DNS, as it is called, refers to the hierarchical naming system used for computers, resources and services on the Internet. It translates the computer hostnames to IP addresses. By way of the implementation of DNS, the domain name 'www.buzzle.com' translates to its IP address, say, 208.70.178.150. With the help of DNS, domain names can be assigned to Internet users. Cyberspace: This term coined by William Gibson, is used to refer to the computer networks connected to each other and the content they host. It is often used to refer to the Internet. WWW: It is a collection of interlinked documents that are accessible over the Internet. It consists of millions of web pages that contain text, images, voice and videos. Sir Tim Berners-Lee, a British scientist working at CERN, created the World Wide Web. W3C: It is the acronym used for the World Wide Web Consortium, which develops standards for the web community. Website: A website is a set of web pages consisting of text, audio and video. Web servers host websites. URL: It specifies the location of a resource on the Internet. It consists of the basic address and path. Web Page: Web pages are resources of information. They are generally created in the HTML format and provide the web users with navigational abilities through hyperlinks to other web pages on the web. Home Page: The term home page is used to refer to the page that is the default page of any website. It is the main page of a complex website. Proxy Server: Client machines on a network connect to the proxy server, which forwards the client requests to other servers and returns responses to the clients. rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 111
  • 113. COMPUTER OPERATIONS PACKAGES Web Server: A web server is a computer program that accepts HTTP requests from web clients and provides them with HTTP responses. Web Browser: A web browser is a software application that facilitates user interaction with the text, audio, video and other information that is located on the web. Cache: Web browsers maintain a cache of recently visited web pages. Some of them use an external proxy web cache, which is a server program through which web requests pass. This enables the browsers to cache frequently visited pages. Even search engines make available already indexed web pages through their caches. HTTP: Hypertext Transfer Protocol, abbreviated as HTTP, is a communications protocol used for the transfer of information over the Internet. A client makes an HTTP request using a web browser to which an HTTP response is sent from the server. Web Cookie: Also known as an HTTP cookie, it is piece of text that is exchanged between the web client and the web server. It is sent by the web server to the web client and returned unchanged by the client each time it accesses the server. You might want to know how do websites use cookies? Session: It is an exchange of information between a computer and its user. It is established for a certain period of time after which it ends. Hyperlink: A reference in a document to another section of the document or to another document is termed as a hyperlink. Hyperlinks are used to redirect the user from one section of a page content to another. Web 2.0: It is used to describe the changes in the www technology and web design. The term deals with the idea of the development of interactivity and connectivity of the web content. Internet security: It is one of the major concerns today. As the Internet acts as a communication platform that can be accessed by millions of users around the world, it becomes necessary that proper measures be implemented. Issues like Internet safety that deal with the content that is made accessible over the Internet are equally important. Internet privacy relates to safeguarding the privacy of the web users and the sensitive information on the web from hackers and stalkers. Internet - A communication Platform Internet serves as one of the most efficient means of communication. Computers from different parts of the world can be connected to each other to exchange information, thanks to the Internet. Emails and chats are excellent means of communication over the Internet. Blogs and online forums give the Internet users a platform to reach out to the masses. Here is a list of the basic Internet terms associated with the Internet as a communication platform. Email: It is a store-and-forward method of writing, sending and receiving written messages. Electronic mail is an Internet e-mail system that uses network-based protocols to exchange messages between network subsystems. Email Address: It identifies the network location to which an email can be delivered. An email address is a combination of the user name of the mail user and the host name of the mailing system. It is of the form, 'username@domain-name'. An email alias is a forwarding email address. It simply forwards emails to specific email addresses. Spamming: The act of sending unsolicited bulk messages over an email system is known as spamming. It is an undesirable use of the electronic messaging systems. Phishing: It is a fraudulent activity of acquiring the sensitive information by the use of a fake identity during electronic communication. It is implemented by means of emails and instant messages wherein a user is lured to enter his/her details, which are actually captured by a fraudulent rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 112
  • 114. COMPUTER OPERATIONS PACKAGES rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 113 website. Hacking: Hacking is the activity of programmatically gaining access to a computer application that is otherwise inaccessible. The act of gaining an unauthorized access to a computer is known as hacking. Hacking of passwords that leads to breach of email privacy is a threat to communication over the Internet. Internet crime refers to all the criminal activities that are carried over the Internet. Email Scams: With the increase in the use of email systems, its security needs also rose. Fraudulent users started tampering with the email systems to breach security. Email Virus: It is a computer code that is transmitted through an email in the form of an attachment. The email attachment causes the destruction of some of the files on the receiver computer's hard disk and is programmatically emailed to the contacts in the address book of the receiver. Email Client: It is also known as a mail user agent (MUA). An email client is a front-end computer program or an agent that acts as a client for the email server. Mail Server: It can also be called Mail Transfer Agent (MTA) and is responsible for receiving incoming email from local users and forwarding outgoing mails for delivery. A mail server application forms the heart of a messaging system that performs all the functions to keep the mails moving over the network. SMTP: Short for Simple Mail Transfer Protocol, SMTP is the standard for the transmission of electronic mails. The electronic mail server software uses SMTP to send and receive mail messages. ESMTP, that is known as extended or enhanced SMTP refers to the protocol extensions made to SMTP and is widely used today. POP3: Short for Post Office Protocol, POP3 is an application layer Internet standard protocol. It is used to retrieve mails from a remote server. Here is a brief introduction to POP3. IMAP: Internet Message Access Protocol, as it is called, is another Internet standard protocol used for retrieval of emails. Internet Chat: It is a real-time Internet chat or synchronous conferencing that is used for group communication as well as one-to-one communication over the Internet. Jarkko Oikarinen, a Ph.D. from the University of Oulu is the developer of the first Internet chat network. He developed the client and server programs for Internet Relay Chat in August 1988. Social Networking: Social networking is about building online communities of like-minded people. Serving as an excellent platform for sharing of information, social networking is a rage today. ADSL: Asymmetric Digital Subscriber Line, abbreviated as ADSL, is used for the transmission of digital information using high bandwidths on existing phone lines. ADSL technology is characterized by high download and low upload rates. Dial-up: It is the means to connect to the Internet using the copper phone lines and a modem. Dial-up connections are capable of sending information from the client's end at very slow speeds of about 56kbps. Modem: It is a device that modulates analog carrier signals to encode digital information and demodulates carrier signals to decode information. A cable modem provides access to data signals sent over the cable television infrastructure. Modems are commonly used for facilitating Internet access. Communication Bandwidth: It refers to the data that can be transferred between two points in a given period of time. It is expressed in terms of bits per second. It is commonly known as the bit
  • 115. COMPUTER OPERATIONS PACKAGES rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 114 rate. Blogs: Blogs are the expressions of the common masses about social or political issues or simply anything. Blogs can often be in the form of creative write-ups by writers in different parts of the world. Internet Forums: It is a bulletin board that serves as a platform for group discussion. Registered users are free to contribute to the issues raised in forums thus making them open discussion platforms. Usenet: Usenet can be considered as a worldwide bulletin board. Usenet newsgroups serve as a repository of messages posted from users around the world. Internet - A Search Platform Internet that hosts an ocean of information has also become an excellent platform for information retrieval. The Internet search engines, which crawl and index web pages, organize the information on the Internet and the web directories link to information on the network. Here is a list of the Internet terms related to the Internet as a search platform. Internet Search Engine: It is an information retrieval system that is designed to help find information over the Internet. Search engines use algorithms to scan the huge information base of the Internet and sort it making it retrievable for the web users. Web Crawler: Popularly known as a spider, a web crawler is a program that browses the World Wide Web in an automated manner. Search engines use the crawling technologies to index pages on the web. Search Engine Optimization: The process of organizing the content of a website with intent to increase its relevance with respect to keywords and search engines. The process of optimization involves editing website content and HTML coding to support search engine strategies of ranking and indexing. Internet Bookmark: The Internet browsers of the modern times aim at enabling the users to organize the web pages they access. Links once visited can be saved in the favorites or preferences categories. Bookmarks are usually integrated into browsers. Social bookmarking is a method used by Internet users to store and manage web pages. Web Directories: It is a directory, which links to other websites and organizes those links. They should not be mistaken as being search engines. OTHER TERMS Router: A router connects two or more logical subnets and performs the functions of routing and forwarding information. Intranet: It is a relatively smaller private network that uses the Internet protocols and connectivity. It is an extension of the Internet and is privately used by organizations. Extranet: It is a private network that uses Internet technology to share a part of the business information and operations with suppliers and customers. It can be a part of a company's intranet that provides access to the users outside the company. Virtual Private Network: It is a private network that allows the exchange of information between computers over a shared or a public network. Wireless Networking: It refers to computer networking that is carried out over the wireless media. Broadband Internet: Broadband connectivity to the Internet provides the users with a high-speed Internet access.
  • 116. COMPUTER OPERATIONS PACKAGES Dial-up Internet: In this type of access to the Internet, the user's computer is attached to a modem connected to a telephone line. Dial-up Internet access involves a modem that dials into an Internet service provider to establish a connection. Satellite Internet: Internet services that make use of the satellite communication media are termed as satellite Internet services. They are used in locations that are mobile thus making terrestrial Internet connectivity, an impossibility. Some Funny and Interesting Internet Terms Googling: The Google search engine, being the most popularly used one, has made the word, 'google' synonymous to the concept of search engines. Searching the Internet by using the Google search engine is known as googling. Copypasta: If text is copy pasted from somewhere and posted in a forum, it is termed as a copypasta. The source is often unknown in such cases. Egosurfer: The web users who search over the Internet for themselves fall under the class of egosurfers. I am sure most of you play an egosurfer once in a while. Netiquette: This term is short for net etiquette and refers to the principles of courtesy and consideration for the people using the Internet. It refers to certain basic principles to adhere to while using the Internet. The general ethical principles to be followed in relation to using mailing systems of the Internet are termed as email etiquette. Trasher: The users who search over the Internet using all possible means, sometimes even risking the Internet security are known as trashers. Troll: Trolls are the users who try to become infamous on chat by introducing disturbing links, mimicking other users' posts and profiles and fighting with others. Youtuber: A person who is addicted to watching videos on the Internet is referred to as a youtuber What are the advantages disadvantages of the Internet? Discuss These are far too broad and extending to all realms in life. For instance:- 1) Access to a wide range of information from any location worldwide where there is internet access. i.e. airlines, resorts, books, authors. 2) Research on any topic i.e. a professor, current affairs. 3) Online Shopping i.e. for cars, specific dress. 4) Online ordering and carrying out other business transactions e.g.. Ordering a cheque book, advertising a product. 5) Online conferencing – communicating across international boundaries. 6) Ability to access e-mail from any location worldwide. 7) Reading newspapers online. Advantages Faster Communication The foremost target of Internet has always been speedy communication and it has excelled way beyond the expectations. Newer innovations are only going to make it faster and more reliable. Now, you can communicate in a fraction of second with a person who is sitting in the other part of the world. For more personal and interactive communication, you can avail the facilities of chat services, video conferencing and so on. Besides, there are plenty of messenger services in offering. With the help of such services, it has become very easy to establish a kind of global friendship rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 115
  • 117. COMPUTER OPERATIONS PACKAGES where you can share your thoughts and explore other cultures. Information Resources Information is probably the biggest advantage that Internet offers. Internet is a virtual treasure trove of information. Any kind of information on any topic under the sun is available on the Internet. The search engines like Google, Yahoo are at your service on the Internet. There is a huge amount of information available on the Internet for just about every subject known to man, ranging from government law and services, trade fairs and conferences, market information, new ideas and technical support, the list is simply endless. Students and children are among the top users who surf the Internet for research. Today, it is almost required that students should use it for research or the purpose of gathering resources. Even teachers have started giving assignments that require extensive research on the Internet. Besides, you can have an access to latest researches in the field of medicine, technology and so on. Numerous web sites such as America's Doctor also allow you to talk to the doctors online. Entertainment Entertainment is another popular raison d'être why many people prefer to surf the Internet. In fact, the Internet has become quite successful in trapping the multifaceted entertainment industry. Downloading games or just surfing the celebrity websites are some of the uses people have discovered. Even celebrities are using the Internet effectively for promotional campaigns. Besides, there are numerous games that can be downloaded for free. The industry of online gaming has tasted dramatic and phenomenal attention by game lovers. Social Networking One cannot imagine an online life without Facebook or Twitter. Social networking has become so popular amongst youth that it might one day replace physical networking. It has evolved as a great medium to connect with millions of people with similar interests. Apart from finding long-lost friends, you can also look for job, business opportunities on forums, communities etc. Besides, there are chat rooms where users can meet new and interesting people. Some of them may even end up finding their life partners. Online Services The Internet has made life very convenient. With numerous online services you can now perform all your transactions online. You can book tickets for a movie, transfer funds, pay utility bills, taxes etc., right from your home. Some travel websites even plan an Itinerary as per your preferences and take care of airline tickets, hotel reservations etc. e-commerce The concept of e-commerce is used for any type of commercial maneuvering or business deals that involves the transfer of information across the globe via the Internet. It has become a phenomenon associated with any kind of shopping, business deal etc. You name a service, and e-commerce with its giant tentacles engulfing every single product and service will make it available at your doorstep. Websites such as eBay allow you to even bid for homes, buy, sell or auction stuff online. rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 116 Additional advantages 1. Global Audience Content published on the World Wide Web is immediately available to a global audience of users. This makes the World Wide Web a very cost-effective medium to publish information. Reaching more than 190 countries. 2. Operates 24 hours, 7 days a week You don't need to wait until resources are available to conduct business. From a consumer's perspective as well as a provider's business can be consummated at any time. The fact that the Internet is operational at all times makes it the most efficient business machine to date.
  • 118. COMPUTER OPERATIONS PACKAGES 3. Relatively Inexpensive It is relatively inexpensive to publish information on the Internet. At a fraction of the cost to publish information by traditional methods, various organizations and individuals can now distribute information to millions of users. It costs only a few thousand dollars to establish an Internet presence and publish content on the Internet. rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 117 4. Product Advertising You can use the World Wide Web to advertise various products. Before purchasing a product, customers will be able to look up various product specification sheets and find out additional information. You can use the multimedia capabilities of the World Wide Web to make available not only various product specification sheets but also audio files, images, and even video clips of products in action. The beauty of the Web is that it allows customers to explore products in as much detail as they desire. If the client just wants a general overview, he or she can look at the advertising information. For those wanting more in depth information, you can provide white papers and product descriptions for download. The Web allows a business to provide timely information, you can simply place the information on the Web page and it is available immediately for your customers. 5. Distribute Product Catalogs The World Wide Web is a very effective medium for distributing product catalogs. In the old days, putting together a product catalog used to be very costly in terms of time and money needed to publish and distribute it. The World Wide Web changes all this by allowing content developers to put together a sales catalog and make it available to millions of users immediately. Furthermore, unlike printed product catalogs that are usually updated around once a month, product catalogs on the World Wide Web can be updated as needed to respond to various changing market conditions. 6. Online Surveys Traditional methods of performing surveys are often relatively slow and expensive compared to online surveys conducted on the Internet. For example, in order to fill out various needs of customers or what they would like to see in a future product, it's often necessary to compile a list of address and mail a questionnaire to many customers. The success of such an attempt is not always guaranteed and can be very costly in terms of mailing the questionnaires and entering responses to a databases and analyzing it. On the other hand, you can use the World Wide Web to automate the whole process. For example, you can set up a CGI script to conduct online surveys. Results of such a survey can be automatically updated to a database. This database can then be used to keep a pulse on various opinions and needs of customers. 7. Announcements With the World Wide Web, you can distribute various announcements to millions of users in a timely manner. Because there is virtually no time lag from the time it takes to publish information to making the information available to users, the Web is an ideal medium to publicize announcements. As more people discover the virtues of the Web and get connected to the Internet, the Web will become the medium of choice for many organizations and individuals to publicize various announcements. 8. Provide Technical Support You can also use Web site to provide technical support to users. Because Web pages can be updated immediately with new information, various technical support literature can be immediately modified in light of new findings and developments. This can be accomplished without having to distribute changes to all users affected by any changes using traditional mediums of information distribution, which are often quite costly compared to the World Wide Web. 9. Create Online Discussion Forums By using applications such as WebBoard, it's possible to set up online discussion forums on the Web. 10. Obtain Customer Feedback The interactive nature of the World Wide Web is ideal for obtaining customer feedback. You can easily set up a CGI script to obtain customer feedback about a product or service. Because customer feedback submitted by customers can be read
  • 119. COMPUTER OPERATIONS PACKAGES immediately, it's possible to respond to various customer concerns in a timely manner, increasing customer satisfaction and quality of customer service. 11. Immediate Distribution of Information When information is added to a Web site, it's immediately available for browsing by millions of Internet users. The World Wide Web is an ideal medium of information distribution because it takes away the time lag associated with publishing content and actually making it available to users 12. Easy Integration with Internal Information Systems Internet information systems deployed on the Internet can be easily integrated with internal information systems managed with office productivity applications such as Microsoft Office. 13. Powerful Content Publishing Tools A new breed of Internet aware applications will start emerging in software stores by the time you read this. These applications will enable users to develop content for the World Wide Web by simply saving as an HTML file. In addition to software developers making existing applications Internet aware, various new, powerful, and easy-to use Internet content publishing applications are also being developed. These applications will make the task of publishing content on the Internet even easier. Most of these applications are developed for Windows users. rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 118 14. Multimedia The capability to incorporate multimedia into Web pages is a major advantage of using World Wide Web to publish information. For example, many Web sites use sounds and video clips to make the content easier and more interesting to browse. 15. Formatting Capabilities Content published on the World Wide Web can be richly formatted by using various HTML tags and graphic formats. The capability to do this is a major reason for the success of the World Wide Web. In addition to using HTML tags and various multimedia formats in Web pages, various interactive controls can also be added to a web page. This capability allows Web site content developers to create active Web sites. For example, before a user sends some information to a Web server for processing, a VBScript or JavaScript subroutine can be used to verify information typed in by the user. Various formatting capabilities, along with technologies such as Java and VBScript, make the World Wide Web a richly interactive medium that you can use to distribute information to millions of users. Disadvantages Theft of Personal Information If you use the Internet for online banking, social networking or other services, you may risk a theft to your personal information such as name, address, credit card number etc. Unscrupulous people can access this information through unsecured connections or by planting software and then use your personal details for their benefit. Needless to say, this may land you in serious trouble. Spamming Spamming refers to sending unwanted e-mails in bulk, which provide no purpose and needlessly obstruct the entire system. Such illegal activities can be very frustrating for you as it makes your Internet slower and less reliable. Virus Threat Internet users are often plagued by virus attacks on their systems. Virus programs are inconspicuous and may get activated if you click a seemingly harmless link. Computers connected to the Internet are very prone to targeted virus attacks and may end up crashing. Pornography
  • 120. COMPUTER OPERATIONS PACKAGES Pornography is perhaps the biggest disadvantage of the Internet. Internet allows you to access and download millions of pornographic photos, videos and other X-rated stuff. Such unrestricted access to porn can be detrimental for children and teenagers. It can even play a havoc in marital and social lives of adults. Social Disconnect Thanks to the Internet, people now only meet on social networks. More and more people are getting engulfed in virtual world and drifting apart from their friends and family. Even children prefer to play online games rather than going out and mingling with other kids. This may hamper a healthy social development in children The Web uses three standards namely: 1 URLs (Uniform Resource Locators) – which are web page addresses 2 HTTP (Hypertext Transfer Protocol) – the language used to design web pages 3 HTML (Hypertext Markup Language) To send e-mail access the Internet, both the sender and receiver need: WHAT IS NEEDED FOR INTERNET AND E-MAIL SERVICES 1) A computer connected to a network, 2) The windows operating system installed 3) The communication and or browser software such as Ms-Exchange or Ms-Outlook, Internet explorer, Netscape navigator 4) A modem 5) Telephone line 6) Subscription to an ISP (Internet Service Provider). What do you need to get connected? To connect to the internet you need: 1) A computer 2) A telephone line 3) A modem - the type of modem you need to use is dependant on the type of connection you have. Some of the choices are: An analogue modem and an ordinary phone line. This type of modem links your computer to the phone and converts computer signals to analogue phone line signals - and back again. Typical analogue modem speeds are 56Kbps (bps stands for bits per second) which means they can receive about 6000 characters per second. This is the slowest and oldest type of connection and becoming less common with the introduction of broadband. An ISDN line and terminal adaptor. This digital connection is slightly faster than an analogue connection. An ADSL or cable telephone line and broadband modem. Broadband modems are much faster than the other two options and their use is increasing. 4) An account with an ISP (Internet Service Provider) 5) Browser software ISPs are the companies who provide you with access to the internet. Commonly used ISPs include Freeserve, AOL, Virgin, Tesco, BT and many more. Most offer the same basic package of Internet access, email addresses, web space for your own pages and local rate call charges. rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 119
  • 121. COMPUTER OPERATIONS PACKAGES A browser is a program that allows you to view the pages on the Web. The most widely used are Internet Explorer and Firefox. All browsers will have a number of similar features to help you use the Web: • Forward and back buttons to move between pages • A history folder which stores details of recently visited web pages • A stop button if a page is taking too long to load • Favorites and bookmark options to store often visited pages • Options to cut, copy, save and print the information viewed Electronic mail Electronic mail or email is a means of sending messages, text, and computer files between computers via the telephone network. Because the telephone network covers the whole world, email enables you to communicate world wide. Email and web mail Email To set up email you need: • A computer • An internet connection via an analogue modem (ordinary phone line) or terminal adaptor (ISDN) or broadband modem (ADSL and cable) • An account with an ISP (Internet Service Provider) • Email software Your Internet Service Provider will give you an email account, a password and a mailbox such as yourname@hostname.co.uk. You can also set up an email account with a mailbox and passwords with non-ISPs such as Google and Hotmail. With a dial-up connection, you have to pay the cost of your internet phone calls (local rate), and in most cases a subscription to your provider (though some are free). A broadband connection is 'always on', with only a flat-rate subscription. Very few people pay by the minute nowadays and the majority of people pay a monthly fee for broadband access. Anti-virus scanning is becoming standard on email accounts and many email providers now offer an anti spam (electronic junk mail) service. Web mail Web mail, as its name suggests, is web-based email. To use web mail, you do not need any email software - just a computer connected to the internet via any one of the connection types listed above, and a browser. Users simply sign up to the web mail service of a web portal such as MSN or Yahoo. They are given a unique user name and a personal mailbox on the portal's email server, and they can then send and receive messages via a special web page. A basic web mail account is usually free, although this will have a very limited amount of storage. The advantage of web mail is that users can receive and send mail from any computer in the world with internet access. If you have a dial-up connection you can download your emails and then read them offline to avoid staying on-line for long periods. Some ISPs will enable their regular email customers to access their mailbox via web mail as well as through the email software on their PC. Features of email • Automatic reply to messages • Auto forward and redirection of messages • Facility to send copies of a message to many people • Automatic filing and retrieval of messages • Addresses can be stored in an address book and retrieved instantly • Notification if message cannot be delivered • Automatically date and time stamped • Signatures can be attached • Files, graphics or sound can be sent as attachments, often in compressed formats • Web mail and mobile email can be used to receive and send messages while on the rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 120 move.
  • 122. COMPUTER OPERATIONS PACKAGES rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 121 Using email • Broadband email - Your connection is always on - so simply write and address your message and hit 'send' to send your mail and 'receive' to download any incoming messages from your email provider's server. • Web mail - Connect to the internet (if using a dial-up account) and open your browser. - navigate to your web mail provider's portal and enter your user-name and password. - all incoming mail will now be visible, and you can also compose and send mail, and download attachments to your computer. - When you're done, log out and close your connection. • Dial-up email - Prepare your message offline as typing your message online will increase phone charges. - Connect to the internet and log on to your email account. - Send your message and download any incoming mail sitting on your service provider's computer. - Log off and close your connection. Email is evolving... • Many mobile phones already allow messages to be sent to the recipient's email inbox while the sender is on the move. The latest generation of mobile phones enables users to send and receive wireless email in exactly the same way as a static computer. • Email can be sent and received via digital TV, specially adapted phones, public kiosk terminals and the latest generation of games console. • A spreading network of wireless 'hotspots' in public places allows people to send and receive email via laptop computers. • A new range of in-car phones will enable motorists to check their email on the road Benefits and concerns of using email Email benefits • Fast delivery of your message • Available 365 days, 24 hours per day - and, with web mail, wherever you are in the world as long as you have access to the internet. • Cheap: when using broadband, individual mail transfers are effectively free. When going online from a dial-up account, calls are charged at local rates and (for conventional email) need only last a few seconds. • Facility to send the same message to more than one person Email concerns • It can only be sent to people who themselves have access to the internet. • Viruses are easily spread via email attachments - anti virus measures must be in place to avoid this and are now offered by many e-mail providers. • Phishing - sending an e-mail to a user falsely claiming to be a legitimate company to scam the user into providing information such as personal information and bank account numbers on a bogus website. The details will then be used for identity theft. • No guarantee the mail will be read until the user logs on and checks their mail. • Spam! Or Junk mail HEALTH AND SAFETY HEALTH PROBLEMS ASSOCIATED WITH COMPUTER USE AND POSSIBLE SOLUTIONS Are Computers a Health Hazard? The first thing to know is that the risks are not likely to affect you unless you are a habitual computer user. In other words, you're sitting at the computer pretty much all day, every day. Oh yeah... that's all of us! That's not to say that the occasional computer user won't have problems. Everyone's level of sensitivity is unique.
  • 123. COMPUTER OPERATIONS PACKAGES The buzz started in the 80's and culminated in the 1992 Health and Safety DSE (Display Screen Equipment) regulations. Then came Carpal-Tunnel Syndrome followed by ergonomics. The hype has subsided, since we all know the computer isn't going to kill us - but we have learned a lot over the past 20 years about potential health risks and more importantly, we've learned ways to avoid being at risk when we're using computers. Let's look at some of the most common medical problems and what you can do to avoid them. rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 122 1. Eye Strain: • Position your terminal at right angles to the window if possible; avoid facing directly into bright light (coming at you from behind your computer screen). • Install an anti-glare screen. • Adjust the brightness controls on the screen until they are comfortable to your eyes. 2. Carpal Tunnel Syndrome: • Adjust your chair or table height to have your elbow angle at 90-100 degrees. • Position your keyboard so that you don't have to bend your hands uncomfortably upward to reach the keys; place a raised wrist rest on the table in front of the keyboard if necessary. • Clinch your fists, hold for one second, then stretch your fingers out wide and hold for 5 seconds. • Organize your workday, if possible, to intersperse other tasks with your computer work so that you're not sitting at the computer for several hours without a break. Variety is key. • Hold the mouse loosely and click lightly. 3. Neck and Back Strain: • Check your posture - sit up straight. Thanks Mom. • The monitor screen surface should be approximately 18-24 inches away from your torso. • Preferably chairs should be on wheels, have backrest tilt adjustment, and have arms. • Be sure you have enough desktop space for work papers and other equipment. 4. Conjunctivitis (itchy, bloodshot eyes) and Dermatitis: • Be sure the screen doesn't flicker or wave - this could indicate that service or adjustment is needed. • Look away from the screen periodically. • Don't forget to blink - your eyes need the moisture. 5. The vision disorder Due to excessive computer use has been identified as Computer Vision Syndrome. Symptoms are dry eyes, headaches, blurred vision, eyestrain, and shoulder back pain. • To alleviate the problem it is suggested that computer users take regular breaks, blink their eyes frequently, occasionally close their eyes for a few minutes and every fifteen minutes or so look away from the computer to stare at an object in the distance. 6. For the back pain and other muscular related problems, It is suggested that people get up every hour, stretch and move around for about five minutes. They should also do an activity which moves each foot and leg. • A computer user should be seated at least two feet away from the screen with the screen below eye level. Their chair should be comfortable and they should sit up straight in the chair with feet firmly on the floor. They should not cross their legs. 7. Posture-related injuries Back and neck pain, headaches, and shoulder and arm pain are common computer-related injuries. Such muscle and joint problems can be caused or made worse by poor workstation design, bad posture and sitting for extended periods of time. Although sitting requires less muscular effort, it still causes fatigue and requires parts of the body to be held steady for long periods of time. This reduces circulation to the muscles, bones, tendons and ligaments and can result in stiffness and pain. If a workstation is not set up properly, these steady positions can put even greater stress on muscles and joints.
  • 124. COMPUTER OPERATIONS PACKAGES Prevention tips – muscle and joint injuries Suggestions to reduce the risk of muscle and joint problems include: • Use an adjustable desk designed for use with computers; position the monitor so that it is either at eye level or slightly lower. • Position your keyboard at a height that allows your elbows to rest comfortably at your side. Forearms should be roughly parallel with the floor and level with your keyboard. • Adjust your chair so that your feet rest flat on the floor. • Use a footstool (if your feet do not rest on the floor when the chair is adjusted for good arm rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 123 position). • Switch to an ergonomic chair, which helps your spine to naturally hold its curve while sitting. • Use an ergonomic keyboard to offer your hands and wrists a more natural holding position. • Take frequent short breaks and go for a walk or perform stretching exercises at your desk. Stand often. 8. Overuse injuries of the upper limbs Muscles and tendons can become painful with repetitive movements and awkward postures. This is known as ‘overuse injury’ and these typically occur in the elbow, wrist or hand of computer users. Symptoms of overuse injuries in the upper limbs include pain, swelling, stiffness of the joints, weakness and numbness. Prevention tips – overuse injuries Suggestions to reduce the risk of overuse injuries include: • Keep your mouse at the same height as your correctly positioned keyboard. • Position the mouse as close as possible to the side of the keyboard. • Use your whole arm, not just your wrist, when using the mouse. • Type lightly and gently. • Mix your tasks to avoid long, uninterrupted stretches of typing. • Remove the hands from the keyboard when not actively typing, to allow the arms to relax. 9. Eyestrain Focusing your eyes at the same distance point for extended periods of time causes fatigue. The human eye structurally prefers to look at objects further than six metres away, so any work performed close-up puts extra demands on the eye muscles. The illuminated computer screen can also contribute to eye fatigue. While there is no evidence that eye fatigue is associated with damage to the eyesight, computer users may experience symptoms such as blurred vision, temporary inability to focus on faraway objects and headaches. Prevention tips – eyestrain Suggestions to reduce the risk of eyestrain include: • Make sure your primary light source (such as a window) is not shining into your face or directly onto the monitor. • Tilt the monitor slightly to eliminate reflections or glare. • Make sure your computer screen is not too close to your face. • Position the screen so that it is either at eye level or slightly lower. • Reduce the contrast and brightness of your screen by adjusting the controls on the monitor. • Frequently look away from the screen and focus on faraway objects. • Have regular eye examinations to check that blurring, headaches and other associated problems are not caused by any underlying disorders. Pain in the buttocks Pain in the buttocks radiating down the thigh can be caused by a chair seat that is too long and causing pressure behind the knees or from inadequate lumbar support. Pain in the shoulders Pain in the shoulders can be caused by having arms on the chair that cannot be adjusted this causes the user to sit with the arms sticking out.
  • 125. COMPUTER OPERATIONS PACKAGES Sitting at the desk with one elbow supported on the desk and the other held lower or twisting the torso to look at the monitor will also cause pain. rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 124 Pain in the knees Pain in the knees can be caused by the fact that when the chair has been adjusted to the correct height to allow the fingers to be horizontal to the keys, the feet are left unsupported, the solution is to purchase a footrest the small step type called (twin plus in the Lyreco catalogue are best because they do not take up much space under the desk, they can be adjusted according to the height of the person using them.) If transcription is carried out it is better to have a large surface area on the footrest and the ability to keep this level to support the footswitch. Pain in the knees can also be caused by a seat that is too long resulting in pressure behind the knees. Eye strain Eyestrain can be caused by glare from the monitor or from overhead lights. Ideally the desk should be placed between lights and not directly under them. If this is not possible you may be able to switch the overhead light off and use an angle poise lamp. Glare from windows without blinds or with incorrectly fitted blinds. Where there are casement window at the top and blinds cannot be used there is often glare from the sun on the screen. Some vertical blinds are not efficient and additional blackout roller blinds would improve efficiency and keep the room cool. If blinds cannot be fitted it may be possible to fit a tinted transparent film to the window. Other solutions: See the Optician about middle distance correction Ask about a slight tinted coating to your glasses Contact IT if there is any flicker on your screen If your monitor is old and small (14inch CGA, VGA) it will have poor resolution and should be replaced with a 17inch SVGA or XGA. Clean your screen Adjust your contrast or brightness Make sure that you are not too far away from the screen (correct viewing distance is 18-20 inches) WORD PROCESSING TERMINOLOGY Spelling checker • A companion application that you use with a word-processing application to check for misspelled words. • A word processing function which searches for and corrects misspellings by comparing a document's words with those in a built-in spelling dictionary. • spell-checker: an electronic dictionary in a word processor that can be used to catch misspelled words • In computing terms, a spell checker or spelling checker is a design feature or a software program designed to verify the spelling of words in a document, helping a user to ensure correct spelling. A spell checker may be implemented as a stand-alone application capable of operating on an block of text; however, spelling checkers are more often implemented as a feature of a larger document-related application, such as a word processor or an email client. Macros • In the context of programming by demonstration, this usually refers to any procedure created by recording the user's actions as they are carried out. Unlike the conventional computer-science definition, the use here does not necessarily have any implications about how the procedure is executed (whether it is expanded in-line using textual substitution or called as a function). • A macro in computer science is an abstraction, whereby a certain textual pattern is replaced according to a defined set of rules. The interpreter or compiler automatically replaces the pattern when it is encountered. In compiled languages, macro-expansion always happens at compile-time. The tool which performs the expansion is sometimes called a macro-expander. ...
  • 126. COMPUTER OPERATIONS PACKAGES rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 125 Header Text that appears at the top of every page of a document when it is printed. Footer • Located at the bottom of the page, it usually contains information about the page author or the sponsor. You may also find copyright information and the date the page was last updated. • Text that appears at the bottom of every page in a document. Mail merge • The process by which information (e.g. names and addresses) from a database or other list and inserted into a standard document or letter to produce multiple personalized copies. • A mass-mail facility that takes names, addresses, and (sometimes) pertinent facts about recipients and merges the information into a form letter or another such basic document. • The transfer of data from one computer file to address and/or personalize mailing items in another. JUSTIFICATION HARD RETURN SPREADSHEET TERMINOLOGY Microsoft Excel is a spreadsheet program written and distributed by Microsoft for computers using the Microsoft Windows operating system and for Apple Macintosh computers. It features an intuitive interface and capable calculation and graphing tools which, along with aggressive marketing, have made Excel one of the most popular microcomputer applications to date. ... Workbook • A spreadsheet document that contains one or more worksheets, a Microsoft Excel document. • A collection of related worksheets contained within a single file. (in spreadsheet applications). • The workbook is the main document used in software programs like Excel. A workbook consists of individual worksheets, like an accountant's workbook, each of which can contain data. Basically, a workbook is a very sophisticated ledger. Worksheet • A single spreadsheet that contains rows and columns of data. In Excel, a worksheet will have a little white tab at the bottom of the screen. A worksheet is treated like a database table. • An electronic spreadsheet containing 256 columns by 16,384 rows. (in spreadsheet applications). • A work area comprised of rows and columns, also known as a spreadsheet. x-axis label • A label describing the x-axis of a chart. (in spreadsheet applications Cell An intersection of a row and column, the smallest element in which you can enter data. Column A vertical selection of cells identified by one or more letters, starting with A at the left side of the spreadsheet. Row A horizontal selection of cells identified by a number, starting with 1 at the top of thespreadsheet. Formula An equation that performs an operation on cell data and displays the result. For example, to add the contents of cells A1 and A2, and display the results in A3, cell A3 would contain =A1+A2, a simple formula. Function A pre-defined formula that allows you to quickly perform a more difficult operation on cell data, such as finding the average of a range of numbers. Functions always take arguments, or additional information that enables the computation to occur. For example, the argument to the AVG, or average, function is the range of cells to be averaged: =AVG(A1..C10) averages all cells between A1 (in the upper left) and C10 (in
  • 127. COMPUTER OPERATIONS PACKAGES rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 126 the lower right). Cell reference • The column number and the row letter of a cell. • The address or name of a specific cell. Cell references may be used in formulas and are relative or absolute. (Spreadsheet application). • A cell name used in a formula. Cell pointer • A highlighted rectangle around a cell that indicates the active cell. (Spreadsheet application) Relative cell reference • Used to indicate a relative position in a worksheet. This allows you to copy and move formulas from one area to another of the same dimensions. Excel, for example, automatically changes the column and row numbers to reflect the new position. (in spreadsheet applications). • Cell references in formulas that change when Excel copies them to another location. Absolute cell reference on the Web: • A cell reference in which a dollar sign ($) precedes both the column and row portions of the cell reference. Mixed cell reference • Cell reference in which either the column or the row is never adjusted if the formula containing it is copied to another location. Cell address • Usually the intersection of a cell's row and column. • Unique location identified by intersecting column and row coordinates. (Spreadsheet application) What if analysis • The process of playing with numbers to see how they interact in a spreadsheet. Freeze panes • Freezing panes prevents the data in the panes from scrolling as you move to different areas in the worksheet. Goal seek on the Web: • Goal Seek is a tool that is used to find the value needed in one cell to attain a result you want in another cell. Formula • A set of instructions that you enter in a cell to perform numeric calculations (adding, multiplying, averaging, etc.); for example, +A1+B1. (in spreadsheet applications) • Instructs the spreadsheet to perform a calculation using the contents of a specific cell or range of cells Filter • A program that processes individual, personal preferences in an attempt to deliver relevant information to a particular end user. Solver • Solver is a tool used to perform what-if analyses to determine the effect of changing values in tow or more cells on another cell. Recalculation • The act of calculating again (usually to eliminate errors or to include additional data); recalculation yielded a much larger value Absolute cell reference: A cell address in a formula that does not change when copied to another cell. An absolute reference has the form $A$1. Active cell: The selected cell in a worksheet. The active cell is surrounded by a heavy border and is identified by the cell address.
  • 128. COMPUTER OPERATIONS PACKAGES rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 127 Argument: The information that a function uses to produce a new value or perform an action. For example, a new value is displayed when the SUM function adds the argument (A6:A12). An argument consists of numbers, references, text, operators, or error values. Ascending: A method of ordering a group of items from lowest to highest, such as from A to Z. AutoFilter: Displays all records that meet the criteria as a subset of the database. AutoFormat: A feature used to format a range of cells with a predefined set of attributes. AVERAGE function: Sums the numbers in the specified range and then divides the sum by the number of non-zero cells in the range. Cell reference: An unique address given to a cell; the coordinates of the intersection of a column and a row. Cell: Basic unit of a worksheet into which you enter data. Chart: A graphic representation of worksheet data. Values from worksheet cells are displayed as bars, lines, or other shapes. Common chart types are pie, bar, line, and area. Column heading: The lettered gray area at the top of each column that identifies the letter of the column, such as column B. Comment: A note that explains, identifies, or comments on the information in a specific cell or range of cells. Condition: Made up of two values and a relational operator, is true or false for each cell in the range. Conditional formatting: Allows you to apply formatting that appears only when the value in a cell meets conditions that you specify. Criteria: The conditions that control which records to display in a query; the words or values used to determine the data that appears in a data list. Currency style format: Displays a dollar sign to the left of the number, inserts a comma every three positions to the left of the decimal point, and displays numbers to the nearest cent (hundredths place). Data table: Range of cells that shows the answers generated by formulas in which different values have been substituted. Data validation: Restricts the values that may be entered into a cell by the worksheet user. Debugging: Process of finding and correcting errors in the worksheet.
  • 129. COMPUTER OPERATIONS PACKAGES rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 128 Descending: A method of ordering a group of items from highest to lowest, such as from Z to A. Dummy data: Used in place of actual data to verify formulas in the template. Embedded chart: A chart that exists on a worksheet instead of on a separate chart sheet. Exploded Pie chart: A Pie chart with one or more slices offset. Filter: A set of criteria you can apply to records to show specific tasks, records, or resources. The tasks, records, or resources that match your criteria are listed or highlighted so that you can focus on just the information you want. Formula: A sequence of values, cell references, names, functions, or operators that produces a new value from existing values. A formula always begins with an equal sign (=). Function: A built-in formula; a named and stored procedure that performs a specific operation and returns a value. Goal seeking: Used if you know the result you want a formula to produce by determining the value of a cell on which the formula depends. Gridlines: The horizontal and vertical lines on the worksheet. IF function: A function that tests the content of the cell, performs a calculation, and displays a value or text based on whether the test is true or false. Label: Row title or column title. Legend: A box containing the name of each data series in a chart. MAX function: Displays the highest value in a range. MIN function: Displays the lowest value in a range. NOW function: Used to enter the system date in a cell in the worksheet. PivotChart: An interactive chart that provides the user with ways to graphically analyze data by varying the fields and categories to present different views. PivotTable: An interactive worksheet table that summarizes data using a selected format and calculations. It is called a pivot table because you can rearrange the table structure around the data.
  • 130. COMPUTER OPERATIONS PACKAGES Protected cells: Cells that you cannot change. rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 129 Range: Series of two or more adjacent cells in a column or row or a rectangular group of cells. Reference: A cell address used in a formula. Relative cell reference: In formulas, a reference to the address of another cell in relation to a cell that contains a formula. Template: Special workbook or worksheet you can create and then use as a pattern to create new, similar workbooks or worksheets. Unprotected cells: Cells whose values you can change at any time. Worksheet: A set of rows, columns, and cells in which you store and manipulate data. Several worksheets can appear in one workbook, and you can switch among them easily by clicking their tabs with the mouse. X-axis: A line, usually horizontal, along the bottom of a chart. The x-axis shows the labels for the data series. Also called the horizontal axis. Y-axis: A line, usually vertical, along the left side of a chart. The y-axis shows the values for the data series. Part A i. Worksheet an electronic spreadsheet containing 256 columns by 16 384 rows. A single spreadsheet that contains rows and columns of data . A set of rows, columns and cells in which you store and manipulate data ii. Cell address usually the intersection of a row and a column. Is the location of a cell on a worksheet and is defined by the column letter and the row number. E.g. cell A1 is where column A and Row 1 intersect. iii. Formula a set of instruction that you enter in a cell to perform numeric calculations = A1+B1 iv. Cell Pointer (cursor) A highlighted rectangle around a cell that indicates the active cell. v. Cell an intersection of a row and column, the smallest element in which you can enter data. Part B i. Footer text that appears at the bottom of every page in a document ii. Text that appears at the top of every page of a document when it is printed. iii. Spell Checker F1 word processing function which searches for and correct misspellings by comparing a document’s words with those in built-in spelling dictionary. iv. Font is a style and size of type e.g Times New Roman, 12 point is a set of all the characters available in one typeface and size, including uppercase and lowercase letters, punctuation, and numerals. v. Alignment the position of lines in a paragraph in relation to the document’s left and right margins i.e. whether they are left-aligned, centered, right-aligned or justified.
  • 131. COMPUTER OPERATIONS PACKAGES a) State the functions of the Control Unit Arithmetic Logic Unit. [5]. Control unit functions Manages input-output to from the main memory Interprets instructions in sequence Issue commands to all elements of the computer Directs sequence of Directs traffic in the computer [make decisions] Interprets coded instructions Initiates proper commands to other parts of the computer. Performs the functions of fetch, decode, execute, and store. Three types of Data Transmission: 1. SIMPLEX Data in a Simplex transmission is always one way. Simplex transmission are not often used because it is not possible to send back error or control It's like a one-way street. An example of simplex is 2. HALF DUPLEX A half-duplex transmission can send and receive in one direction, but not at the same time. It's like a one-lane bridge where two-way traffic must give way in order to cross. Only one end transmits at a time, the other end receives. In addition, it is possible to perform error detection and request the sender to retransmit information that arrived corrupted. In some aspects, you surfing as being half-duplex, as a user issues a request for a web document, then that document is downloaded and displayed before the user issues another request. Another example of half-duplex is talkback radio, and CB Radio (Citiz movies where a truck driver (drivers of very big trucks) communicates to each other, and when they want the other person to speak they say over. This is because only one person can talk at a time rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm A.L.U functions Performs arithmetic operations Performs logical operations Performs computations on data. operations Is where binary data is acted upon? Stores intermediate and final results of arithmetic operations forms signals to the transmit end. television, or Radio. can think of Internet Citizens Band). You might have seen 130 ens
  • 132. COMPUTER OPERATIONS PACKAGES 3. FULL DUPLEX Data can travel in both directions simultaneously. There is no need to switch from transmit to receive mode like in half duplex. It like a two lane bridge on a two two-lane highway. Have you ever watched these television talk shows where the host has a number of peopl at once. Well, that's full duplex! Of course, in the world of data communications, full duplex allows both way communications simultaneously. An example can be a consumer, which uses a cable connection not only, rece channels, but also the same cable to support their phone and Internet surfing. All these activities can occur simultaneously. Practical QUESTION a. Name any 2 word processing packages b. What is page break in word processing and why is it used c. How do you save a file on a floppy disk using the word processor you have d. How do you underline a block of previously typed text using the word processor you have studied? e. Explain the difference between i. SAVE SAVE AS rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm people on the show, and they all try to talk packages. used/ studied? 131 e receives TV
  • 133. COMPUTER OPERATIONS PACKAGES ii. COPY CUT iii. DELETE BACK SPACE iv. PORTRAIT LANDSCAPE v. TOGGLE CASE UPPERCASE f. Briefly outline the procedures for performing the following functions in a windows environment. i. Creating a folder ii. Opening a folder iii. Searching folders or files iv. Renaming a file or folder v. Creating a shortcut for a file or rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 132 folder vi. Copy file from one folder to another vii. Move a file from one folder to another viii. Deleting a file or folder ix. Arrange icons on the desktop x. Change screen saver xi. Click xii. Right click xiii. Double click xiv. Drag xv. Loading windows xvi. Shutting down a computer xvii. Emptying recycle bin xviii. g. Briefly outline the procedures for performing the following functions using a spreadsheet of your choice i. Expanding a cell ii. Adding a list of figures in the range A10 to D10 iii. Insert a full border around a document iv. Adding and Renaming Worksheets v. Resizing Rows and Columns
  • 134. COMPUTER OPERATIONS PACKAGES h.Briefly outline the procedures for performing the following functions using a word processor of your choice rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 133 1. Opening a Microsoft word program for typing 2. Saving a document 3. Retrieving a document 4. Setting landscape or portrait orientation 5. Print preview 6. Formatting text into italics 7. Setting left and right margins 8. Inserting a header or a footer 9. Open a document which has been saved before 10. Insert a picture 11. Insert a table 12. Printing a word document 13. Exit MS Word 14. Save a document 15. Copy a document or a word 16. Double line spacing 17. Insert a header 18. Insert page number 19. Save a document onto a floppy disk 20. Mail merge 21. JUSTIFYING TEXT 22. Inserting bullets 23. Indenting text 24. Moving a block of text 25. Copying a block of text 26. Creating a table 27. Adding rows to a table 28. Adding columns to a table 29. Deleting rows of a table 30. Deleting columns of a table 31. Shading a table 32. Merging cells of a table 33. Splitting cells 34. Changing text direction 35. Inserting drop caps 36. Having 2 columns on a word document 37. Bordering and shading a paragraph 38. Change case of a word 39. Locking a word file with a password Question 26 (a) Discuss any 4 possible uses of spreadsheets in a business organization. [8 marks] (b) Explain the following terms as used in spreadsheets I. Cell II. Range. [2 marks each] (c) Explain the following terms as used in a word processing I. Soft return II. Hard return III. Thesaurus IV. Widow V. Orphan. [2 marks each] Question 24 (a) Define an electronic spreadsheet. [3 marks] (b) List 5 facilities provided by a spreadsheet. [5 marks] (c) What is word processing? [2 marks] (d) Explain the following word processing terms I. Justification II. Hard return III. Soft return IV. Header V. Orientation. [2 marks each] Question 15 Briefly explain the following terms as used in a spreadsheet (a) Active cell (b) Cell (c) Legend (d) What if analysis (e) Label (f) FUNCTION (g) GRAPH (h) Formula (i) Cell address (j) Worksheet (k) Cell reference (l) Relative cell reference (m) Cell pointer (n) Absolute cell reference (o) Mixed cell reference (p) Work book (q) Goal seek (r) Range (s) Protected cells (t) Freeze panes
  • 135. COMPUTER OPERATIONS PACKAGES (u) Embedded chart (v) Row column rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 134 [1 mark each] Question 16 Briefly explain the following terms as used in a Word processing (a) Orphan (b) Header (c) Footer (d) TEMPLATE (e) Spellchecker (f) FONT (g) TAB STOPS (h) Mail merge (i) Font type (j) Justification (k) Word wrap (l) Bold (m) Borders (n) Bullets (o) Hard return (p) STATUS BAR (q) Indentation (r) Soft return (s) Widow/Orphan Control (t) Widow (u) Thesaurus (v) Format bar (w) Standard bar (x) Center alignment [1 mark each] Question 6 (a) Define a word processor give an example [2 marks] (b) List down at least 5 facilities provided by a word processor [5 marks] (c) Give a suitable term/ phrase that best describes the following statements in word processing. i) The automatic movement of typed text to the new line, without pressing the enter key. ii) Different “handwritings” in a computer. iii) Line spacing. [1 mark each] (d) Define a spreadsheet and give an example [2 marks] (e) Give the difference between a spreadsheet a worksheet [2 marks] (f) Give a suitable word/ phrase that best describes the following spreadsheet terms I. Cell [2 marks] II. Hard copy [2 marks] III. Creating a permanent copy of a worksheet on a computer. [2 marks] QUESTION 31 (a) Define the term Operating System. [3 marks] (b) State any 4 functions of an operating system. [4 marks] (c) State any 3 examples of an Operating system (exclude the Windows family). [3 marks] (d) Define the following Windows Operating Systems based terms: I. Desktop II. Icon III. Taskbar IV. Window V. Cascade window [2marks each] Question 6 Expand the following abbreviations. a) GIGO b) WYSIWYG c) LED d) LCD e) MS DOS f) OCR g) MICR h) CD ROM i) ASCII j) COM k) WIMP l) GUI m) WIMP n) CRT o) DBMS p) POP 3 q) HTML r) URL s) TCP-IP t) CAD u) RAM v) ROM w) DSS x) LAN y) 4GL z) UPS aa) PABX bb) DRAM cc) SRAM dd) EFT ee) WAN ff) PC
  • 136. COMPUTER OPERATIONS PACKAGES rrmmmmaakkaahhaa@@ggmmaaiill..ccoomm 135 gg) MIS hh) EBCDIC ii) MHz jj) OMR kk) SDLC ll) HTTP mm) C PU nn) DBA oo) EPROM pp) VDU qq) ALU rr) DOS ss) FORTRAN tt) COBOL uu) ISP vv) CPU ww) W WW xx) DVD yy) VOIP zz) ISDN aaa) U RL bbb) P ROM[20 marks] Question 7 Explain the following terms in detail, giving examples where applicable. a) Computer peripherals b) Program c) BLUETOOTH d) Computer e) Hardware f) Software g) Operating system h) Application software i) Utility software j) Machine language. k) Random access memory. [20 marks] Question 8 Explain the following terms as used in word processing or spreadsheet a) Menu b) Footer c) Soft return d) Edit e) Cell f) Label g) Chart h) Mail merge i) Print preview j) Work sheet. [2 marks each] Questions (a) Discuss any 4 possible uses of spreadsheets in a business organization. [8 marks] (b) Explain the following terms as used in spreadsheets I. Cell o The intersection of a row and a column on a spreadsheet in which data can be entered. II. Range. o Series of two or more adjacent cells in a column or row or a rectangular group of cells. III. [2 marks each] (c) Explain the following terms as used in a word processing VI. Soft return o A soft return is entered automatically by a word processor's word wrap feature when the text reaches the end of the line. It is contrasted with a hard return which is used primarily to begin a new paragraph. A little known feature of Microsoft Word and OpenOffice. ... VII. Hard return o Made by pressing the return or enter key on the keyboard. A hard return, or carriage return, creates a line break and identifies the end of a paragraph. VIII. Thesaurus
  • 137. COMPUTER OPERATIONS PACKAGES 136 o Provides a listing of words and their synonym/related words. o Guide to use of terms, showing relationships between them, for the purpose of providing standardized, controlled vocabulary for information storage and retrieval IX. Widow o In typesetting, a widow occurs when the majority of a paragraph appears on one page with the last line of that paragraph flowing to the top of the following page. ... o The last line of a paragraph at the top of a page of text. X. Orphan. o In typesetting, an orphan is the first line of a paragraph appearing on its own at the bottom of a page with the remaining portion of the paragraph appearing on the following page. The first line of the paragraph was left behind by the remaining portion of text. ... o Line of type on its own at the bottom of a page. [2 marks each] Question 24 (a) Define an electronic spreadsheet. [3 marks] (b) List 5 facilities provided by a spreadsheet. [5 marks] (c) What is word processing? [2 marks] (d) Explain the following word processing terms VI. Justification a. In typesetting, justification (can also be referred to as 'full justification') is the typographic alignment setting of text or images within a column or measure to align along both the left and right margin. Text set this way is said to be justified. b. The alignment of text in a paragraph so that the margins are all straight on the right side, or the left side, or both. E.g. this text is left justified. VII. Hard return VIII. Soft return IX. Header o Text that appears at the top of every page of a document when it is printed. X. Orientation. o Whether page is vertically or horizontally aligned. For example we have portrait and landscape orientation. o Portrait orientation. The mode in which content is viewed where the width is shorter than the height. Portrait orientation mimics the way most reading material is printed, eg, letters, newspapers, books. ... o Landscape orientation. The mode in which content is viewed where the width is longer than the height. Landscape is the traditional orientation for computer viewing and is appropriate when viewing spreadsheets, video games, and movies. [2 marks each] Question 15 Briefly explain the following terms as used in a spreadsheet (a) Active cell (b) Cell (c) Legend (d) What if analysis (e) Label (f) FUNCTION (g) GRAPH (h) Formula (i) Cell address (j) Worksheet (k) Cell reference (l) Relative cell reference (m) Cell pointer (n) Absolute cell reference (o) Mixed cell reference (p) Work book (q) Goal seek (r) Range (s) Protected cells (t) Freeze panes (u) Embedded chart (v) Row column [1 mark each]
  • 138. COMPUTER OPERATIONS PACKAGES 137 Question 16 Briefly explain the following terms as used in a Word processing (a) Orphan (b) Header (c) Footer (d) TEMPLATE (e) Spellchecker (f) FONT (g) TAB STOPS (h) Mail merge (i) Font type (j) Justification (k) Word wrap (l) Bold (m) Borders (n) Bullets (o) Hard return (p) STATUS BAR (q) Indentation (r) Soft return (s) Widow/Orphan Control (t) Widow (u) Thesaurus (v) Format bar (w) Standard bar (x) Center alignment (y) Hyphenation – is used to eliminate gaps in justified text or to maintain even line lengths in narrow columns. You can hyphenate manually or automatically. [1 mark each] Question 6 (g) Define a word processor give an example [2 marks] (h) List down at least 5 facilities provided by a word processor [5 marks] (i) Give a suitable term/ phrase that best describes the following statements in word processing. i) The automatic movement of typed text to the new line, without pressing the enter key. ii) Different “handwritings” in a computer. iii) Line spacing. [1 mark each] (j) Define a spreadsheet and give an example [2 marks] (k) Give the difference between a spreadsheet a worksheet [2 marks] (l) Give a suitable word/ phrase that best describes the following spreadsheet terms IV. Cell [2 marks] V. Hard copy [2 marks] VI. Creating a permanent copy of a worksheet on a computer. [2 marks] QUESTION 31 (e) Define the term Operating System. [3 marks] (f) State any 4 functions of an operating system. [4 marks] (g) State any 3 examples of an Operating system (exclude the Windows family). [3 marks] (h) Define the following Windows Operating Systems based terms: I. Desktop o The main workspace in a graphical user interface such as Windows or Macintosh Systems. Users open and work with files and programs on the desktop, and can store files and shortcuts there as well. The user can also customize the look of the desktop with images or wallpaper and custom icons. o Is the background screen on the computer? It consists of pictures, called icons that show cabinets, files, folders, and various types of documents. II. Icon o A picture or graphical representation of an object on a display screen to which a user can point to with a device, such as a mouse, to select a particular operation or perform a certain action. III. Taskbar o The bar usually found at the bottom of a Windows screen. The taskbar shows which software programs are open. It also contains the Start button. o A windows 95/98 screen elements, displayed on the desktops which includes
  • 139. COMPUTER OPERATIONS PACKAGES 138 the start button and lists the programs currently running on the computer. IV. FOLDER o Folder, a virtual container within a digital file system, in which groups of files and other folders can be kept and organized. V. WIMP o WIMP (Windows Interface Manipulation Program, also refers to Windows, Icons, Menus and Pointing device - the prehistorical GUI of the 1970's) is a program for creating full-screen visual animations synchronized with sound in real time. As the only visual input WIMP utilizes graphical user interface (GUI) of Windows operation system. Whatever applications windows, icons, images, texts, etc. you have open on your desktop - they become an inspiration source for WIMP and you. Animations are generated by simple 2- and 3-D effects and filters and their superimpositions. As such WIMP can be used as a VJ tool, a screensaver, a cool grafix generator or as a piece of conceptual art. VI. RECYCLE BIN o In the Microsoft Windowsoperating systems, the Recycle Bin is a holding area for files and folders that are held before final deletion from a storage device. VII. GUI o A graphical user interface (GUI) is a type of user interface item that allows people to interact with programs in more ways than typing such as computers; hand-held devices such as MP3 Players, Portable Media Players or Gaming devices; household appliances and office equipment with images rather than text commands. A GUI offers graphical icons, and visual indicators, as opposed to text-based interfaces, typed command labels or text navigation to fully represent the information and actions available to a user. The actions are usually performed through direct manipulation of the graphical elements.[1] VIII. Window o In computing, a window is a visual area, usually rectangular in shape, containing some kind of user interface, displaying the output of and allowing input for one of a number of simultaneously running computer processes. ... IX. Cascade window o An arrangement of Windows so each window is neatly stacked with only the title bar of each window is showing. o Arrange (open windows) on a computer desktop so that they overlap each other, with the title bars visible [2marks each] Question 7 Explain the following terms in detail, giving examples where applicable. a) Computer peripherals b) Program c) BLUETOOTH a. Bluetooth® is the codename for a technology specification for low-cost, short-range radio links between mobile PCs, mobile phones and other portable devices, and connectivity to the Internet. ... b. Bluetooth is the name given to a radio technology making transmission of signals over short distances between telephones, computers and other devices, like household appliances, without the use of wires. d) Computer e) Hardware f) Software g) Operating system h) Application software i) Utility software j) Machine language. k) Random access memory. [20 marks] Question 8
  • 140. COMPUTER OPERATIONS PACKAGES 139 Explain the following terms as used in word processing or spreadsheet k) Menu a. A list of options, each of which performs a desired action such as choosing a command or applying a particular format to a part of a document. Menus are commonly used in graphical interfaces. l) Footer m) Soft return n) Edit o To review a piece of writing, marking and correcting grammatical, spelling, and factual errors. The editing process also often includes shortening or lengthening articles to fit available space, writing headlines and subheads. o) Cell p) Label q) Chart r) Mail merge s) Print preview t) Work sheet. [2 marks each]
  • 141. COMPUTER OPERATIONS PACKAGES rmmakaha@gmail.com 140 ABBREVIATIONS 1) ALU Arithmetic Logic Unit 2) ARC net Attached Resource Computer Network 3) ASCII American Standard Code for Information Interchange 4) B2B Business-To-Business 5) BCD Binary Coded Decimal 6) BIOS Basic Input/Output System 7) BIS Business Information System 8) BIT Binary Digit 9) BLOG Web Log 10) BSYNC Binary Synchronous Communications (protocol) 11) C C Programming Language 12) CAD Computer Aided Design 13) CAL Computer Aided Learning 14) CASE Computer Aided Software Engineering 15) CDMA Code Division Multiple Access 16) CD-R Compact Disk - Recordable 17) CD-ROM Compact Disk - Read Only Memory 18) CD-RW Compact Disk - Rewritable 19) COBOL Common Business-oriented Language (See HLL) 20) CODEC Coder/Decoder + Compression/Decompression 21) COE Common Operating Environment 22) CPU Central Processing Unit 23) CRC Cyclic Redundancy Check 24) CRT Cathode Ray Tube 25) CSMA/CA Carrier Sense Multiple Access/with Collision Avoidance 26) CSMA/CD Carrier Sense Multiple Access/with Collision Detection 27) CSMS Customer Support Management System 28) DSS Decision Support System 29) DTE Data Terminal Equipment + Dumb Terminal Emulator 30) DVD Digital Video Disk 31) DVD-A Digital Video Disk-Audio 32) DVD-AR Digital Video Disk-Audio Recording 33) DVD-R Digital Video Disk-Recordable 34) DVD-RAM Digital Versatile Disc-RAM 35) DVD-ROM Digital Versatile Disc-ROM 36) DVD-SR Digital Video Disk-Stream Recording 37) DVD-VR Digital Video Disk-Video Recording 38) DVR Digital Video/Voice Recorder 39) EBCDIC Extended Binary Coded Decimal Interchange Code [IBM] 40) EEPROM Electrically Erasable Programmable Read-Only Memory 41) EFTS Electronic Funds Transfer System 42) E-MAIL Electronic Mail 43) EPROM Electrically Programmable Read Only Memory + i. Erasable Programmable Read Only Memory 44) FTP File Transfer Protocol [Internet] 45) FDDI Fiber Digital Device Interface + i. Fiber Distributed Data Interface 46) FDISK Fixed Disk 47) FDM Frequency Division Multiplexing 48) FDMA Frequency Division Multiple Access 49) FDX Full Duplex 50) FEC Forward Error Correction 51) FM Frequency Modulation 52) FORTRAN Formula Translator (Programming Language)(See HLL) 53) FTP File Transfer Protocol 54) GHZ Gigahertz
  • 142. COMPUTER OPERATIONS PACKAGES 55) GIGO Garbage In, Garbage Out 56) GIS Geographic Information System 57) GSM Global System for Mobile-Communications (network) 58) GUI Graphical User Interface 59) HDD Hard Disk Drive 60) HDLC High-Level Data Link Control 61) HLL HIGH LEVEL LANGUAGE 62) HDTV High Definition Television 63) HTML HyperText Markup Language 64) HTTP HyperText Transfer Protocol 65) Hz Hertz 66) IP Internet Protocol 67) IQL Interactive Query Language 68) ISDN Integrated Services Digital Network 69) IT Information Technology 70) LAN Local Area Network 71) LCD Liquid Crystal Display 72) LED Light Emitting Diode 73) LPT Line Printer Terminal 74) LPT1FirstParallelPrinterPort 75) LPT2SecondParallelPrinterPort 76) LPT3 ThirdParallelPrinterPort 77) MBps Megabytes Per Second 78) Mbps Megabits Per Second 79) MBR Master Boot Record 80) MHz Megahertz 81) MICR Magnetic Ink Character Recognition 82) MIDI Musical Instrument Digital Interface 83) MIS Management Information System 84) MODEM Modulator/Demodulator 85) MP3 MPEG Audio Layer 3 86) MSAV Microsoft Anti Virus [Microsoft] 87) MS-DOS Microsoft - Disk Operating System [Microsoft] 88) PDF Package Definition File + Portable Document Format + i. Portable Document File + Processor Defined Function + ii. Program Development Facility 89) .PDF Printer Description (file name extension)[Borland, Lotus] 90) P2P Peer To Peer + People To People 91) USB Universal Serial Bus 92) WYSBYGI What You See Before You Get It 93) WYSIWYG What You See Is What You Get rmmakaha@gmail.com 141
  • 143. COMPUTER OPERATIONS PACKAGES Basic Computer Terminology Computer has turned from being just a technological gadget to personal PC to a super technological personal gadget. There is nothing in the world that does not depend on computers. You need to understand the basic computer terms and meanings in order to stay up-to-date with the world. If you do not know the basic computer terms and definition, you look like a lost soul in the most happening world of technology. You need to book a movie ticket, so you need Internet access. You have to submit a presentation for your company's project, you need a computer to bail you out. Its out of date to use a video cassette for your recordings. Cassettes are like an ancient relic, its CD's and DVDs that are in vogue today. And to top it all, USB flash drives have created a niche in the minds of tech-savvy people. So before you float your mind in the floating point numbers or scratch your head when learning the queries in databases, let us begin with some simple basic computer terms for beginners. Basic Computer Terms and Definitions Computer A computer is a computing device that is similar to an automated abacus that can execute a program, that is, a sequence of automatic instructions. Program A program is a is an executable software that runs on a computer. It contains compiled codes that run directly from the computer's operating system. Operating System The operating system (OS) is the software that communicates with the computer hardware on the primary level. No software can be run on the computer without the operating system. It serves as a user interface and helps allocating memory, processes tasks, accesses disks and peripheral. Command A command is a series of step by step instructions that helps the computer perform a specific action. CPU The central processing unit or CPU, also known as the microprocessor or processor is the brain of the computer. It helps execute instructions in a software program and helps retrieve instructions form the computer's memory, comprehending and executing instructions and helping direct the input and output of the computer. Desktop The computer monitor or the screen of the computer against which, the operating system and access application programs, files and documents are displayed is called the desktop. File The file is a unit for information storage that includes word-processor, spreadsheet, pictures, music, etc. Each file is differentiated with the help of a unique file name. Folder The folder is a unique system that helps in organizing the files, topics, programs and projects on the computer. The similar applications in a folder will be grouped together when an application rmmakaha@gmail.com 142
  • 144. COMPUTER OPERATIONS PACKAGES program is loaded. It is similar to organizing files on a shelf in your cabinet. Hard Drive The hard drive is the region where the information is stored and helps the computer to permanently retain and store the data. Hardware The computer system that comprises of a computer, that is, monitor, keyboard, mouse, printer, computer unit, scanner, etc. is known as the hardware. When the CPU is opened, the components that make a CPU are also the hardware. You can read and learn more on computer hardware basic information. Hyperlink An hyperlink is a program that helps one move from one web page to another. The text is underlined and the cursor that moves over this text document, takes the shape of a hand. This means there is a hyperlink added to the text and you can click on it to move over to another page or document. Internet The Internet is a world wide network that helps connect millions of users around the world to share and exchange data, information, opinions, etc. The Internet is not similar to World Wide Web (WWW). The WWW is a service that is provided on the Internet for the users. Monitor The computer monitor is defined as the computer screen or display unit. The monitor helps in displaying the user interface and programs. It is a way for the user to interact with the computer, using the keyboard and mouse. Mouse Do not be baffled, a computer mouse is a hand held device that helps the user move across the flat surface and help control the pointer on the screen. It is a very accessible device, as it helps one move faster across the screen and perform many tasks quickly. Keyboard The computer keyboard is the peripheral unit of the computer that helps in typing in the words and numbers along with the symbols and thus communicate with computer. In other words, it is the way, how you can feed in information that needs to processed into your computer. You can read more on computer keyboard shortcuts. RAM Random Access Memory or RAM is the temporary storage space in the computer that helps place information so that is can execute the program and instructions given. Once a program is closed, the data is removed from RAM. The amount of RAM helps in determining the number of programs that can be run. Browser The web browser is an application that helps render the source code of World Wide Web or web pages that can be used by the user. The information is rendered in understandable form for the user by the browser. The Microsoft Internet Explorer is an example of the browser. Peripherals The peripherals are the input devices that are connected to the machines. The keyboard, mouse and printer are computer peripherals. Some peripherals are important for the working of the machine and some are added components, without which one can work on the computer. Networks The network is a physical or logical construction that connects different computers together and helps them communicate. The computer networking is carried out through cabling or through rmmakaha@gmail.com 143
  • 145. COMPUTER OPERATIONS PACKAGES wireless networking. The best example is the Internet that helps sites to connect on different computers. Software The instructions that are provided to the computer with step-by-step actions that help executing a specific task is a software. A computer cannot function without a software. These were a few basic computer terms for kids that can be helpful for a beginner to understand the computer parts list. Computers have become a part and parcel of our daily lives, without which we cannot function. Man has become so dependent on the computer that a minor computer glitch can send life into a tizzy. One needs to learn using a computer, as much as he needs to learn how to read and write. Today, people breath software and eat hardware (hypothetically speaking). You do not want to be left out in this rat race of technically sound world. So begin by learning and teaching your kids these basic computer terms for beginners. rmmakaha@gmail.com 144 QUIZ A B C D 1 You have completed the document and want to make certain that you have not made spelling or grammar errors. Which button do you select? 2 Text is selected and you want to remove the selection from the active document and place it on the clipboard. Which button do you select? 3 You have made a change to the active document and want to make certain that those changes are saved. Which button do you select? 4 A phrase will appear several times in the document. To save time you have selected the phrase and want to copy it. Which button do you select? 5 The document had been checked for spelling errors, it has been saved, and now you are ready to print. Which button do you select? 6 A document which has been saved into a folder on your computer is to be opened so changes can be made. Which button do you select? 7 The document had been checked for spelling and has been saved. Before sending it to the printer you want to see how it will look. Which button do you select?
  • 146. COMPUTER OPERATIONS PACKAGES A B C D rmmakaha@gmail.com 145 1 Instead of striking the underline key fifteen times, you plan to draw a single line by clicking and dragging. Which button do you select? 2 You have drawn a line, and now want to change the color of the selected line. Which button do you select? 3 The last line you drew had an arrowhead at the wrong end. You want to change the arrowhead to the other end of the line. Which button do you select? 4 You created an object in a document and you want to tilt it at an angle. Which button do you select? 5 You have drawn a rectangle around a section of a flyer and want to change it to a dashed line. Which button do you select? 6 The heading of a flyer is just plain text and you would rather create special effects with text. Which button do you select? 7 You are going to draw a perfect circle on your document by holding down the shift key, clicking and dragging. Which button do you select? A B C D 1 You wish to call attention to a statement in your document by making the text bold. Which button do you select? 2 A flyer is to be prepared inviting parents to a performance. You want the headline to be centered on the page. Which button do you select? 3 You want to make sure that your instructions are clear and plan to place them in a
  • 147. COMPUTER OPERATIONS PACKAGES bulleted list. Which button do you select? rmmakaha@gmail.com 146 4 To call attention to a block of text, you want place a block of color behind the text to highlight it. Which button do you select? 5 Another way to call attention to a block of text is to place a border around it. Which button do you select? 6 A quoted block of text has been indented. You wish to continue the document but you need to undo the indent. Which button do you select? 7 You have made a birthday certificate and you want the student's name to be displayed in color. Which button do you select?