Introduction to computer office 2003

A KCSE Computer Studies Presentation
TOPIC:
INTRODUCTION TO COMPUTER
PREPARED BY: Maurice Atika Nyamoti 1
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INTRODUCTION TO COMPUTER
Definition of a computer
Common terminologies used in computer
Parts of a computer
Examples of peripheral devices
Development of Computers
Classification of computers
Areas where computers are used
The computer laboratory
Hands-on-Skills
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Definition of a computer
Just like other machines, computers make work easier.
Majority of people refer a PC (personal computer) as
the real computer, however a mobile phone, calculator,
weighing machine, watch, washing machines etc are
also computers as such.
You can define a computer according to what it does,
thus a computer can be described as a device that
processes data into information
A computer can also be described as an electronic
device that saves, transmits and processes data into
information.
Example: a calculator is able to add 1+1 to get 2. thus 1+1
represents data and 2 represents information.

Common terminologies used in computer
 Data- it simply refers to a collection of
numbers, characters which have no much
meaning to the user.
 Information-is a sequence of numbers and
characters which can be interpreted as
having meaning. Information can also be
described as processed data
 A computer Program- is a sequence of
instructions written to perform a specified
task with a computer.
 Input stage- this stage involves entering
data into the computer using input devices
i.e. keyboard
 Processing- this stage involves processing
of data using processing devices i.e. the
CPU
 Output stage- this stage involves the
processing outcome that will be displayed
by output devices i.e. the screen
INPUT
PROCESSING
OUTPUT
STORAGE
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Parts of a computer
A Computer has so many
parts that work together to
process data. However
there are four major parts
that make up a computer
and these include: System
unit, Screen, Keyboard and
mouse
Other parts include:
scanners, drives, cards,
modems, speakers, printers
etc.
Anything attached to the
system unit is referred to as
a peripheral device
System unit Screen Mouse
Keyboard Drive
Modem printer Card

Examples of peripheral devices
A computer can have as many peripheral devices as it can hold. They range from
the screen, mouse, keyboard, webcam, camcorder, printer, modem, scanner,
joystick, trackball, projector, digital camera, speakers, microphone, stylus etc

Development of Computers
Abacus, believed to exist before Christ, was used by Asian merchants
to calculate complex mathematical calculations.
In 1830s Charles Babbage designed an analytical engine which is
believed to be the mother of all modern computers.
In 1939, Howard Aiken of Harvard University designed a fully
automatic calculator called Mark 1.
From 1939-1946, at the Univ. of Pennsylvania introduced ENIAC
(electronic numeric integrator and calculator). It is believed to be the
first all-purpose electronic digital computer that used thousands of
vacuum tubes and produced a lot of heat.
In 1951,UNIVAC (UNIVersal Automatic Computer) became the first
computer to handle both numeric and alphabetic data with equal
facility; this was the first commercially available computer.
1957 to date, smaller but more powerful computers were discovered
which were more capable of transmitting, processing and saving data
of large amounts. Had higher speed, produced less heat and processed
on microprocessors. These computers are today referred to as third
and fourth generation computers

Development of Computers
The table below shows a summary of development of computers
Age Name Advancements Use
Before
Christ
Abacus It was made of wood and
beads.
Used by Asian merchants to count wealth
1614-1620 Log tables Paper and pen Used to calculate complex mathematical expressions
1647 Mechanical
calculator
calculator To solve complex mathematical expressions
1792-1871 Analytical
engine
Computer Combine arithmetic process with decision based on
its own computer
1946-1956 First
generation
computers
Computer (used thermionic
valves and vacuum tubes to
process data)
Store and Process Data
1957-1963 Second
generation
computers
Computer (used
transistors to process
data)
Store and Process Data
1964-1979 Third
generation
computers
Computer (used integrated
circuits (ICs) to process
data)
Store, transmit and Process data with better
storage and increased speed of processing
1979-1989 Fourth
generation
computers
Computer (used VLSI-very
large scale integrated
circuits to process data)
storage and increased speed of processing than 3G
computers
1990-
present
Fifth
generation
computers
Computer (use advanced
VLSI in the name of
microprocessor to process
data)
storage and increased speed of processing, small in
size and emit less heat and consumes less power.
Faster than 4G computers and also portable.

Computers can be classified according to physical size, functionality
and purpose as shown in the organizational chart below
Classification of computersClassification of computers
1. Physical size1. Physical size 3. Purpose3. Purpose
2. Functionality2. Functionality
1. Classification according to physical size
Physical sizePhysical size
• Super computers• Super computers
• Main frames• Main frames • Mini computers• Mini computers • Micro computers• Micro computers
Classification of computers

1. Description of computers according to physical size
Size Characteristics Uses
super computers Largest, fastest, powerful and most
expensive. they also generate a lot of
heat
Used for advanced
scientific research such
as nuclear physics.
Main frames Less powerful and less expensive than
super computers. They also have a
large storage capacity
Used to handle all kinds of problems
whether scientific or commercial. I.e.
performing complex mathematical
calculations. they are mostly found in
banks, hospitals, airports etc.
Mini computers Smaller and less powerful than the
main frame
Used in scientific laboratories, research
institutions, engineering plants and
places where processing automation is
required.
Micro computers Smallest, cheapest and relatively least
powerful. Uses a micro processor to
process data. Examples: desktop,
laptop and personal digital assistant
(PDA)
Used to perform a variety of tasks
including research, communication,
banking, learning institutions, libraries
etc.

2. Classification according to functionality
Classification according to functionalityClassification according to functionality
AnalogueAnalogue DigitalDigital HybridHybrid
Computer Characteristics Uses
Analogue Process data that is
discrete in nature
Used by PCs, home appliances, TVs,
Microwaves, wall clocks etc
Digital Process data that is
continuous in nature
Used in manufacturing process control
like monitoring temperatures, pressures,
density etc
Hybrid Designed to process both
analogue and digital data
Used on manufacturing process control.
And returns a digital value. Examples
are:- a digital weighing machine, digital
thermometer etc

3. Classification according to purpose
Classification according to purposeClassification according to purpose
General purposeGeneral purpose Dedicated computersDedicated computers
Special purposeSpecial purpose
Computer Uses Examples
General purpose Designed to perform a
variety of tasks
PCs, cell phones, notebooks
etc.
Special purpose Designed specifically for
one task
Calculators, robots, cell
phones, thermometers etc
Dedicated computers Designed as a general
purpose but dedicated to
perform a specific task
PCs used for learning
environment, banking,
communication etc.

Functions of a computer:
The main functions of a
computer are:
•
Saving data
•
Processing data
•
Transmitting data
•
Detecting events
Purpose of a computer
The main purpose of a
computer is to help the user
accomplish a specific
computational task i.e.
calculating mathematical
and logical expressions,
transmitting data signals
and saving data for future
reference.

Areas where computers are used
Just like all other machines, computers are used in a day-to-day life to make work easier and more efficient. Some
important application areas of a computer are given below.
Area Uses
Industry and
Commerce
Saving records, security, real-time response, automating records, communication, process
control, detection, manufacturing, accounting etc
Health Care Save records, diagnose patients, scanning of body parts, security, management of records,
communication, research, consultations, preserving bodies etc
Government
Institutions
To save and manage records of people, vehicles, activities etc, plan government calendars,
security, forecasting and drawing of budgets, communication, research activities, traffic control
etc
Education and
Research
Learning aids, research tools, keeping research records, budgeting, accounting, security,
forecasting, communications, consultations etc
Communication
Industry
Prepare programs on TV/Radio, broadcasting, producing music, tracking activities, automating
communication processes, relay of telephone signals etc
Police and Defense Tracking criminals, keeping records, used in forensic labs to filter DNA and fingerprints,
controlling traffic, communication, automating armory, military vehicles and tanks, controlling
CCTV cameras, keep track of temperatures in nuclear stations etc.
Home and Leisure Entertainment, used as TV, Radio, DVD player etc, communication, security, keeping home
records and budgeting family finances, can be used as a diary, notebook or an address book, etc
Transport and
tourism
Hotel booking system, marketing, air travel, booking and control system, communication and
research, traffic light system, shipping and sea navigation, security etc.
Agriculture Keeping inventory record, controlling farm machinery, keeping track of plants and livestock,
research and consultations, diagnosing farm diseases and pests, tracking livestock movements,
breeding and health records, irrigation etc.

The computer laboratory
A computer lab is a room set aside for installation and use of computers.
Safety precautions and practices in the computer lab
Computer systems are expensive to acquire and maintain, and should therefore handled with care.
Causes of computer damage and measures to avoid them
1. Dust and Smoke
- dust and smoke damage the surface of the hard disk and other moving parts. To avoid them:
•Avoid smoking in the computer lab
•Cover computers with dust covers
•Put curtains along the windows
•Avoid entering the lab with muddy shoes
•Use the dust blower to blow off dust from the computers more often
2. Water and Humidity
- humidity is the amount of water vapor in the air. Water and humidity can cause rusting and if
water spills on sensitive computer parts, it can cause short circuiting thus damaging the
components. To avoid this kind of scenario:
•Avoid entering the computer lab with drinks and beverage.
•Install the computer lab with humidifiers and dehumidifiers to keep humidity at bay.
•Don’t put a water based fire extinguisher in the computer lab
•Avoid splashing water when washing the computer lab. Though, vacuum cleaning is
recommended.

•Temperature
initially computers are installed with a heat sink and a fan to cool down the CPU when it’s processing.
Too much heat can break down the CPU or cause delay in processing. Therefore the computer lab must
be kept with cool temperatures in the following ways:
•Avoid overcrowding of computers and users
•The computer lab should be well ventilated
•Consider installing air conditioning system
•Uncover computers when using them
•Power Fault
-Electricity is the most precious need in any computer lab. It is also the most dangerous if not properly
used. Power surge and brownouts are responsible for damaging computers. To avoid this:
• Avoid unnecessary movements in the computer lab to avoid hitting power cables
• Keep water off the power sockets
• Switch off the computer and the monitor immediately incase power fault has been detected
• Avoid children/pets in the computer lab
• Consider installing AVS switches (automatic voltage switches) to stabilize power
• Use UPS (uninterruptible power supply) to regulate power before entering into the computer. They can
also be used to alert the user when power goes off.
• Electric lines should always be insulated to avoid electrical shocks. They should pass in trunks along
the edges of the wall into the strategically positioned sockets.

Data security and burglar proofing
-data theft and stealing of computers should be kept into consideration when building
the computer lab. To avoid this:
• Install security alarms
• Shut down the computer using the right procedure
• Put metallic grills at the doors and windows, strong roof and CCTV (closed circuit
television) cameras
• Usually use passwords and encrypt confidential data. A password is a secret code
the user must provide before accessing computer resources. Data encryption is the
process of encrypting/encoding data in way that only the sender and the receiver can
understand. For one to read this data, an encryption key (like a password) is required.
• Consider hiring security personnel
• Do not welcome strangers into the computer lab.
Fire
- fire can physically damage computers. To avoid fire:
• Do not smoke in the computer lab
• Install a gaseous fire extinguishers
• All electrical cables should be laid properly.

Measures to protect the user
• All cables should be insulate and laid away from busy
paths
• Provide standard furniture i.e. the seat should have a
straight backrest and the table should be strong enough
to support computers and their peripheral devices
• Avoid overcrowding
• Provide anti radiation (anti-glare) screens to filter light.
as shown in the diagram below:
• The room should be properly lit and ventilated
Anti-radiation/glare screen

Hands-on-Skills
STARTING A COMPUTER
•Starting a computer is easy for the user since it involves pressing the
power button of the monitor then that of the system unit. WHY? While
the system unit is switched on, it checks whether all components
(hardware) attached to it are functioning in a process called POST (power-
on-self-test). Therefore the screen should be switched on first in order to
enable POST to take place. Power button is denoted by the following
symbol:
• The process of starting up a computer is referred to as booting
•There are two types of booting, namely,
1. Cold booting- a process of starting a computer that was initially
off.
2. Warm booting- a process of re-starting a computer/starting a
computer that is already on.

HOW A COMPUTER STARTS STEP -BY –STEP
STEP 1: when you press the power button, the computer sends a signal to the power
supply to convert AC (alternating current) into DC (direct current). In order to
supply the computer with proper electric current and voltage.
STEP 2: once power has been received by every component and no error is reported,
a signal is sent to the motherboard by the CPU that the computer is ready to
processes instructions contained in the (BIOS) basic input/output system.
STEP3: once the computer looks at the BIOS, it begins the POST process. This
ensures that all peripheral devices are present and functioning properly. If one
device fails the test, booting process halts.
STEP 4: NEXT the computer looks at the memory located at the complimentary
metal oxide semiconductor(CMOS) chip. Which is kept alive by the internal battery.
CMOS keeps manufacturer’s settings and system date and time. That is why the
CMOS must always be on even though the computer is switched off, thanks to the
internal battery.
STEP5: The computer will then start comparing system settings of your CMOS with
the operating system (i.e. Windows XP) installed in your computer. If no errors
occur, the post will start to load basic drivers for your hardware and interrupt
handlers such as the mouse, keyboard, network adapters etc this enables programs
to communicate with devices and allow booting process to carry on.

HOW A COMPUTER STARTS STEP -BY –STEP
STEP6: the POST will check the real-time clock (RTC) or system timer and the computer system
bus to make sure both of these are properly working on the computer. Finally, you'll get a picture
on your display after the POST has loaded the memory contained on the display adapter and has
made it part of the overall system BIOS
STEP7: Next, the BIOS will check to see if it's currently performing a cold boot or warm boot
(reboot) by looking at the memory address 0000:0472, if it sees 1234h the BIOS knows that this is
a reboot and will skip the remainder of the POST steps.
If 1234h is not seen, the BIOS know that this is a cold boot and will continue running additional
POST steps. Next, it tests the computer memory (RAM) installed in the computer by writing to
each chip. With many computers, you'll know it's performing this step if you see the computer
counting the total installed memory as its booting.
STEP8: the POST will send signals to the computer floppy, optical, and hard drive to test these
drives. If all drives pass the test, the POST is complete and instructs the computer to start the
process of loading the operating system.
STEP9: After the computer has passed the POST, the computer will start the boot process. This
process is what loads the operating system and all of it’s associated files. . Because Microsoft
Windows is the most commonly used operating system, this section will cover the process of
loading Microsoft Windows.
STEP10: After the computer has loaded the operating system, hardware attached to the
computer must be able to communicate with the CPU. Once the operating system has finished
loading, a log in display window is displayed for the user to access the computer resources.

•Shutting down a computer is a procedural
process just like starting up a computer.
Instant shutdown can damage computer
programs and components thus making a
system to malfunction.
•Before shutting down a computer, make
sure that all active programs are closed and
important documents are saved to avoid loss
of unsaved data. Then proceed as follows:
1.From the taskbar, click the start button.
2.From the sidekick menu that appears,
select turn off computer
3.Then click turn off from the dialog window
that appears.
4.Wait until the system shuts down by itself
then press the power button of the monitor
to shut it off.
5.Finally, switch off the power source.
SHUTTING DOWN A COMPUTER
Task bar
Turn off window
Start menu

KEYBOARD SKILLS
How to use actual/physical keyboard effectively
1. Sit upright and maintain an alert posture
2. Place the material to be typed in a position you can read without straining
3. Put feet flat on the floor
4. Arch your wrist
5. Keep a good eye line
6. Position hands on home row (left hands: a, s, d, f, right hand: j, k, l,;,)
7. Use your left index finger to hit the g, t, r, v, b, 5, and 6 keys.
8. Use your left middle finger to hit the e, c, and the 3 keys
9. Use your left ring finger to hit the w, x, and 2 keys
10. Use your left ring finger to hit the w, x, and 2 keys
11. Use your left pinky to hit the q, z, and the 1 key.
12. Use your right index finger to hit the y, u, h, n, m, 6, 7, and 8 keys.
13. Use your right middle finger to hit the u, <, and 9 keys.
14. Use your right ring finger to hit the o, ., and the 0 keys.
15. Use your thumbs to strike the space bar.
16. Use your right hand on the num pad. Place your index finger on the 4. Your middle finger on the 5.
Your ring finger on the 6, and your pinky on the enter key. Place your thumb on the 0. Strike the 7 and 1
with your index finger. Strike the 8 and 2 with your middle finger. Strike the 9 and 3 with your ring finger.
Strike the - and + with your pinky.

Get a typing tutor installed in your computer. You can get this from us at a reasonable fee.

MOUSE SKILLS
Just like a keyboard, a mouse is used to input data into the computer. As the mouse
moves, it moves the pointer on the screen into a position defined by the user. Pressing
on the mouse button is referred to as clicking. Clicking performs a number of functions
but the most important is to enable the user to execute a command in the computer
comparable to pressing the enter key on the keyboard.
Mouse Terminologies
Clicking:
pressing the left mouse button once
Double clicking:
pressing the left mouse button twice in quick succession to open a file/folder
Drag and Drop:
placing the pointer on a file/folder/graphic, then press the left button and hold.
Move the pointer to the designated place and let go the left button. Used to move
objects from one location to another.
Right clicking:
pressing the right mouse button once. Provides a dropdown list for the user to
choose from. comparable to pressing the menu key on the keyboard.
Scrolling:
rolling the scroll wheel at the top of the mouse to view hidden data across
windows

Conclusion
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 Maurice Atika Nyamoti studied computer engineering at Maseno university /99
has taught various computer colleges, St Mary’s Girls Thigio and attended
various workshops of computer studies and computer and society. He is now the
Director of manyamfranchise.com a firm that deals with computers and
computer learning materials. He is also the author and publisher of KCSE
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http://www.facebook.com/andus.a.nyamoti

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