Introduction to Computer, Basis of ICT in Detail

Introduction To Computer
• For all academic departments affiliated with University of Malakand.
• BS Botany (3rd semester)
• BS Chemistry (3rd semester)
• BS Computer Science (1st semester)
• BS Economics (1st semester)
• BS English (2nd semester)
• BS Islamic Studies (3rd semester)
• BS Mathematics (1st semester)
• BS Pashto (3rd semester)
• BS Physics (3rd semester)
• BS Political Science (3rd semester)
• BS Sociology (1st semester)
• BS Urdu (3rd semester)
• BS Zoology (3rd semester)
Written by: Syed Pir Zada
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ICT
Information and Communication
Technologies
(According to New Course contents)
Written By: Syed Pir Zada
Lecturer in Computer Science.

Computer
• A computer is an electronic device which
accepts input data with the help of input
devices, processes that data, stores that data
till needed and produce output with the help
of output devices.
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Structure of computer
INPUT
Central Processing
Unit (CPU)
Memory
Output
All Computers Perform four basic operations.
1. Input operation: It is the process of accepting data or information from the
user using input devices.
2. Processing operation: It is the transformation process of converting the
input into output. CPU performs processing operation.
3. Storage operation: It is the process of storing data either temporarily or
permanently using storage devices.
4. Output operation: It is the process of displaying information to the user
with the help of output devices.
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Control Unit
Arithmetic and logic Unit
Secondary memory
Primary memory
Input Output
CPU
Memory / Storage
Detailed Structure of Computer
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Data and information
• Data
– Data is the collection of raw facts and figures.
– Data is a collection of unorganized facts & figures
and does not provide any further information
regarding patterns, context, etc. Hence data
means "unstructured facts and figures".
• Information:
– Processed form of data is called information.
Information is a structured data i.e. organized
meaningful and processed data.
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Types of data
• Alphabetic data/textual data
• Numeric data
• Alphanumeric data
• Audio data
• Video data
• Graphical data
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Information communication
technologies
• Information and communication technologies
(ICT) is defined as a set of technological tools and
resources used to create, store, share or
exchange information.
• These technological tools and resources include
computers, the Internet (websites, blogs and
emails), live broadcasting technologies (radio and
television), telephony (fixed or mobile, satellite,
video-conferencing, etc.).
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Applications of computer
• Computers play an important role in every field of
life. Here are the list of uses or applications of
computer.
1. Home
2. Medical field (Health)
3. Entertainment
4. Education
5. Government
6. Banking
7. Business
8. Science and engineering
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• Home
– Computers are used at homes for several
purposes like online bill payment, watching
movies, home tutoring, social media access,
playing games, internet access, etc.
– They help to avail work from home facility for
employees.
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• Medical Field.
– Computers are used in hospitals to maintain a
database of patients’ history, diagnosis, X-rays,
live monitoring of patients, etc.
– Surgeons nowadays use robotic surgical devices
to perform operations, and conduct surgeries
remotely.
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• Entertainment
– Computers help to watch movies, playing games,
listening to music etc.
– Different types of entertainment fields such as
multimedia, film making with animation, graphics,
audio and visual design are done with the help of
computer.
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• Education:
– Computers are used in education sector through
online classes, online examinations, online
tutoring, etc.
– Computer-based training (CBT) and Computer
Aided Design (CAD) is used to train their to train
students and employees, to save money and
improve performance.
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• Government:
– In government sectors, computers are used in
data processing, maintaining a database of citizens
and supporting a paperless environment.
– The country’s defense organizations have greatly
benefitted from computers in their use for missile
development, satellites, rocket launches, etc.
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• Banking:
– In the banking sector, computers are used to store
details of customers and conduct transactions,
such as withdrawal and deposit of money through
ATMs.
• Business:
– Computers are used in businesses. The main
objective of business is transaction processing of
suppliers, employees and customers. Computers
can make these transactions easy and accurate.
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• Science and Engineering:
– Computers are used in the field of research and
development. Scientists use computers to plot
and analyze data to have a better understanding.
– In engineering, the construction layouts are
designed beautifully on system using different
tools and softwares.
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Types of computer
computer
Digital
computer
Analog
computer
Hybrid
computer
There are three main types of computers
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1. Digital computers
• Digital computer operates on digital data and
provides output in digital form. It uses binary
number system in which there are only two digits
0 and 1. Each one is called a bit.
• Digital computers process data in the form of
digits. All operations take place at high speed and
produce accurate and precise results.
• It works on discrete values (not continuous)
• All modern computers like laptops, desktops
including smartphones that we use at home or
office are digital computers.
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2. Analog computers
• This computer accepts an analog input and
convert these information into another form to
produce output.
• Analog Computers work on continuous range of
values. An analog computer is generally used for
measurement.
• It generally deals with physical variables such as
distance, length, height, temperature, speed, etc.
• Mostly used in engineering and science fields.
• Example are automobile speedometer, weight
machine, thermometer,
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3. Hybrid computers
• A hybrid computer combines the best features
of both analog and digital computers to solve
a problem. Hybrid computers have the speed
of analog computers and accuracy of digital
computers.
• Its input can be analog as well as digital.
• These computers are used in specialized
applications like flight radar system, national
defense, digital petrol pumps etc.
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Hybrid computer
Blood pressure and ECG Machine
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Input devices
• Following are some of the important input devices which are used
in a computer.
– Keyboard
– Mouse/mice
– Joy Stick
– Light pen
– Track Ball
– Scanner
– Microphone
– Digital cameras
– Magnetic Ink Card Reader(MICR)
– Optical Character Reader(OCR)
– Bar Code Reader
– Optical Mark Reader(OMR)
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Keyboard
• Keyboard is the most common
and very popular input device
which helps to input data to
the computer.
• The layout of the keyboard is
like that of traditional
typewriter, although there are
some additional keys provided
for performing additional
functions.
• Keyboards are of two sizes 84
keys or 101/102 keys, but now
keyboards with 104 keys or
108 keys are also available for
Windows and Internet.
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Keyboard keys
• Typing Keys
• These keys include the letter keys (A-Z) and digit keys (0-9) which generally give
the same layout as that of typewriters.
• Numeric Keypad
• It is used to enter the numeric data or cursor movement.
• Function Keys
• The twelve function keys are present on the keyboard which are arranged in a row
at the top of the keyboard. Each function key has a unique meaning and is used for
some specific purpose for example F1, F2, … , F12
• Control keys
• These keys provide cursor and screen control. It includes four directional arrow
keys. Control keys also include Home, End, Insert, Delete, Page Up, Page Down,
Control(Ctrl), Alternate(Alt), Escape(Esc).
• Special Purpose Keys
• Keyboard also contains some special purpose keys such as Enter, Shift, Caps Lock,
Num Lock, Space bar, Tab, and Print Screen.
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Mouse/Mice
• Mouse is the most popular pointing
device. It is a very famous cursor-
control device having a small palm
size box with a round ball at its base
(laser light nowadays), which senses
the movement of the mouse and
sends corresponding signals to the
CPU when the mouse buttons are
pressed.
• Generally, it has two buttons called
the left and the right button and a
wheel is present between the
buttons (optional).
– Easy to use
– Not very expensive
– Moves the cursor faster than the arrow
keys of the keyboard.
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Joystick
• Joystick is also a pointing
device, which is used to move
the cursor position on a
monitor screen. It is a stick
having a spherical ball at its
both lower and upper ends.
The lower spherical ball moves
in a socket. The joystick can be
moved in all four directions.
• The function of the joystick is
similar to that of a mouse. It is
mainly used in Computer
Aided Designing (CAD) and
playing computer games.
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Light Pen
• Light pen is a pointing device
similar to a pen. It is used to
select a displayed menu item
or draw pictures on the
monitor screen.
• It consists of a photocell and
an optical system placed in a
small tube.
• When the tip of a light pen is
moved over the monitor
screen and the pen button is
pressed, its photocell sensing
element detects the screen
location and sends the
corresponding signal to the
CPU.
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Scanner
• Scanner is an input device,
which works more like a
photocopy machine. It is used
when some information is
available on paper and it is to
be transferred to the hard disk
of the computer for further
manipulation.
• Scanner captures images from
the source which are then
converted into a digital form
that can be stored on the disk.
These images can be edited
before they are printed.
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Microphone
• Microphone is an input
device to input sound
that is then stored in a
digital form.
• The microphone is used
for various applications
such as adding sound to
a multimedia
presentation.
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Digital cameras
• Digital cameras are also
computer input devices.
They range from high-
end DSLR(digital single
lens reflex) cameras to
digital video cameras to
inexpensive webcams.
Cameras are a fast way
to get a lot of graphic
information into a
computer at one time.
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Magnetic Ink Card Reader (MICR)
• MICR input device is generally
used in banks as there are
large number of cheques to be
processed every day. The
bank's code number and
cheque number are printed on
the cheques with a special
type of ink that contains
particles of magnetic material
that are machine readable.
• This reading process is called
Magnetic Ink Character
Recognition (MICR). The main
advantages of MICR is that it is
fast and less error prone.
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Optical Character Reader (OCR)
• OCR is an input device
used to read a printed
text.
• OCR scans the text
optically, character by
character, converts
them into a machine
readable code, and
stores the text on the
system memory.
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Bar Code Readers
• Bar Code Reader is a device
used for reading bar coded
data (data in the form of light
and dark lines). Bar coded data
is generally used in labeling
goods, numbering the books,
etc. It may be a handheld
scanner or may be embedded
in a stationary scanner.
• Bar Code Reader scans a bar
code image, converts it into an
alphanumeric value, which is
then fed to the computer that
the bar code reader is
connected to.
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Optical Mark Reader (OMR)
• OMR is a special type of
optical scanner used to
recognize the type of
mark made by pen or
pencil. It is used where
one out of a few
alternatives is to be
selected and marked.
• It is specially used for
checking the answer
sheets of examinations
having multiple choice
questions.
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Output devices
• An output device is a piece of computer
hardware which is used to produce the
output either in soft form or hard form.
• An output device is any peripheral device that
receives data from a computer and produce
output.
• Following are some of the important output
devices used in a computer.
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Monitors
• Monitors, commonly called as Visual Display
Unit (VDU), are the main output device of a
computer. It forms images from tiny dots, called
pixels that are arranged in a rectangular form.
The sharpness of the image depends upon the
number of pixels.
• There are two kinds of viewing screen used for
monitors.
• Cathode-Ray Tube (CRT)
• Flat-Panel Display
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Cathode ray tube
• The CRT display is made
up of small picture
elements called pixels.
The smaller the pixels, the
better the image clarity or
resolution. It takes more
than one illuminated pixel
to form a whole
character, such as the
letter ‘e’ in the word help.
• disadvantages of CRT:
– Large in Size
– High power consumption
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Flat-Panel Display Monitor
• The flat-panel display
refers to a class of video
devices that have
reduced volume, weight
and power requirement
in comparison to the
CRT. You can hang them
on walls.
• Advantages:
– Small in size
– Less power required
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Printers
• A printer is an external hardware output
device that takes the electronic data stored on
a computer or other device and generates
a hard copy.
• Printers are one of the most popular
computer peripherals and are commonly used
to print text and photos.
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Printers
• There are different types of printers
• Character printers
– Print one character at a time.
• dot matrix printer
• Daisy wheel printer
• Line printers
– Print one line at a time
• Drum printer
• Chain printer
• Page printers
– Print one page at a time
• Laser printers
• Inkjet printers
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Laser Printers
• These are non-impact page
printers.
• When a document is sent to
the printer, a laser beam
"draws" the document on a
drum using electrical
charges. After the drum is
charged, it is rolled in toner,
a dry powder type of ink.
The toner sticks to the
charged image on the drum.
The toner is transferred
onto a piece of paper.
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• Advantages
– Very high speed
– Very high quality output
– Good graphics quality
– Supports many fonts and different character size
• Disadvantages
– Expensive
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Inkjet Printers
• Inkjet printers are non-impact character printers
based on a relatively new technology. They print
characters by spraying small drops of ink onto
paper. Inkjet printers produce high quality output
with presentable features.
• They make less noise because no hammering is
done and these have many styles of printing
modes available. Color printing is also possible.
Some models of Inkjet printers can produce
multiple copies of printing also.
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• Advantages
– High quality printing
– More reliable
• Disadvantages
– Expensive as the cost per
page is high
– Slow as compared to
laser printer
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Plotters
• A plotter is a special output device used to
produce hard copies of large graphs and
designs on paper, such as construction maps,
engineering drawings, architectural plans and
business charts.
• The plotter is either a peripheral component
that you add to your computer system or a
standalone device with its own internal
processor.
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Speakers
• Speakers – are attached
to computers for the
output of sound. Sound
cards are required in
the computer for
speakers to
function. Speakers
range from simple, two-
speaker output devices
to surround-sound
multi-channel units.
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Headset
• Headset is a
combination of
speakers and
microphone. It is
mostly used by gamers
and is also great tool for
communicating with
family and friends over
the internet.
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Projector
• Projector – is a
display device that
projects a computer-
created image.
The computer transmits
the image data to
its video card, which then
sends the video image to
the projector. It is usually
used for presentations or
for viewing videos.
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Memory
• Computer memory is any physical device
capable of storing information temporarily or
permanently.
• A memory is just like a human brain. It is used
to store data and instructions. Computer
memory is the storage space in the computer,
where data is stored.
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Units of memory
• The smallest unit of memory is bit
• 4 bits= 1 nibble
• 8 bits= 1 byte
• 1 kilo byte (KB)=1024 bytes
• 1 mega byte (MB)=1024 KB
• 1 giga byte (GB) = 1024 MB
• 1 tera byte (TB)=1024 GB
• 1 peta byte (PB)=1024 TB
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Types of memory
Memory
Primary
memory
RAM ROM
Secondary
Memory
Magnetic
disks
Hard disk
Floppy
disk
Optical
Disks
CD DVD
Magnetic
tapes
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Primary memory
• Also called main memory and volatile memory
• Primary memory holds only those data and
instructions on which the computer is
currently working. It has a limited capacity
and data is lost when power is switched off
that’s why it is called volatile memory. It is
generally made up of semiconductor device.
• There are two types of primary memory
• RAM and ROM
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i. Random Access Memory (RAM)
• A type of computer memory that can be accessed
randomly, that is, any byte of memory can be
accessed directly by the processor.
• The data stored in this part can be read, changed
and erased completely.
• RAM needs power to retain its data, when the
power is switched off data is washed out.
• When computer is power on, programs and data
are loaded into RAM.
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ii. Read Only Memory (ROM)
• The data stored in ROM is permanent and is not
lost due to light failure or switching off the
computer.
• Data stored in ROM cannot be changed or
removed or written to it. Thus referred to as non
volatile memory.
• Most personal computers contain a small amount
of ROM that stores critical programs such as the
program that boots the computer.
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Secondary memory
• Also known as auxiliary storage, external storage,
backup storage, long term storage, permanent storage.
• A secondary storage is a device in which data is stored
for long time. Data can also be erased. The purpose of
using this storage is:
– To provide long term storage for data which are not being
executed currently.
– To give additional memory space to computer.
– To speed up the accessing of data which is not possible in
the case of only using RAM.
– To provide permanent storage so that the electricity failure
or switching off the computer does not harm the data.
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Secondary storage devices
• Floppy disk:
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i. Floppy disk
• It is a flat circular plate, coated with a
magnetic material and then enclosed in a
plastic jacket.
• It is used as a storage device.
• These are of two types: one is 51/2 inch disk
capable of storing 1.2 MB of data and the
other is 31/2 inch disk capable of storing 1.44
MB data.
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Hard disk
• Also called disk drive, hard drive, or hard disk drive.
• It is a circular metallic plate which is thick in size
• It is permanently enclosed in air tight jacket to exclude
dust.
• It can store large amount of data and has faster access
speed than floppy disks.
• The circular disk is divided into circular tracks.
• Tracks are divided into sectors.
• A read/write head is used to read data from hard disk
and to write / store data into hard disk.
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iii. compact disc (CD)
• A compact disc is a portable storage medium that can
be used to record, store and play audio, video and
other data in digital form.
• A standard compact disc measures 4.7 inches, or 120
millimeters (mm), 1.2 mm thick, weighs between
15 grams and 20 grams, and has a capacity of 80
minutes of audio, or 650 megabytes (MB) to 700 MB of
data.
• A CD works by focusing a laser onto a single track of
the disc. As the disc rotates, the laser beam measures
differences in the way light is reflected off converting it
to sound.
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iv. DVD
• Short for digital versatile disc or digital video
disc, a DVD or DVD-ROM is a disc capable of
storing a significant amount more data than a
standard compact disc. DVDs are widely used
for storing and viewing movies and other data.
• Its working mechanism is same as that of CD.
• To read and play DVDs on a computer, you
must have a DVD-ROM drive and DVD player
software.
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iv. Magnetic tapes
• Magnetic tape is a long and
narrow strip of plastic that
thin magnetic material is
coated on. Nearly all
recording tape is of this
type, whether used for
recording audio or video or
computer data storage.
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Magnetic tapes
• Devices that record and playback audio and
video using magnetic tape are generally
called tape recorders.
• A device that stores computer data on
magnetic tape can be called a tape drive.
• It is a sequential access memory.
• Used for back up and archives.
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Cache Memory
• Cache memory is high-speed static random
access memory (SRAM) that a processor can
access more quickly than it can access regular
random access memory (RAM).
• Cache memory is placed between main memory
and processor to speed up processing.
• Those instructions/data are stored in cache
memory which are used repeatedly by the CPU.
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Levels of cache memory
• Level 1 (L1) cache (primary cache), is extremely
fast but relatively small in size and is usually
placed in the processor chip as CPU cache.
• Level 2 (L2) cache (secondary cache), is often
large in size than L1 but slower than L1. it is
placed at some distance from the CPU.
• Level 3 (L3) cache is specialized memory
developed to improve the performance of L1 and
L2. L1 or L2 can be significantly faster than L3,
though L3 is usually double the speed of RAM.
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Flash memory
• Flash memory is a non-
volatile memory chip
used for storage and for
transferring data between
a personal computer (PC)
and digital devices. It has
the ability to be
electronically
reprogrammed and
erased. It is often found in
USB flash drives, MP3
players, digital cameras
and mobile phones.
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Computer system
• There are two main components/elements of
a computer system.
Computer
Software Hardware
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Hardware
• Computer hardware are the physical parts or
components of a computer which can be
touched.
• Tangible components such as the monitor,
keyboard, mouse, CPU, Memory etc.
• Hardware is directed by the software to
execute any command or instruction. A
combination of hardware and software forms
a usable computing system.
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Software
• Software is a collection of instructions that
enable the user to interact with a computer,
its hardware, or perform specific tasks.
• without software, most computers would be
useless. For example, without your
Internet browser software, you could not surf
the Internet and without an operating system,
the browser could not run on your computer.
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• It can be a single program or may refer to a
number of programs collectively. These
instructions are defined in proper step by step
manner.
• A software acts as an interface between user
and hardware.
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Types of software
• The computer software is broadly divided into
two types.
• System software
• Application software
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System software
• System software are set of programs that
operate and control the computer system.
• System software is a type of
computer program that is designed to run a
computer’s hardware and application
programs.
• Examples are operating system (OS), device drivers
BIOS etc.
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System software
• System software does the following jobs.
– Support the development of other software.
– Support the execution of other software.
– Monitors the efficient use of various hardware
resources.
– Communicate with and controls the operations of
peripheral devices.
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Application software
• Application software is a type of software that
can be used for a variety of tasks.
• Application software is a program or group of
programs designed for end users according to
their needs such as creating documents,
spreadsheets, databases, doing online
research, sending email, creating graphics,
playing games etc.
• Examples are MS word, Excel, PowerPoint, Paint,
CorelDraw, browser, media players etc.
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Components of computer system
• The computer system can be divided into four components
as follows.
1. Hardware: the physical components which can be touch
and see like memory, CPU, storage, input and output
devices etc.
2. Operating system: OS controls and coordinates the use of
hardware among various application programs for users.
3. Application programs: those softwares which are used by
users for variety of tasks like MS word, excel, paint,
browser etc.
4. Users: those people who uses the computer are called
users.
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Operating system
• An operating system is a program (system
software) that manages and operates
computer hardware.
• An operating system (OS) is the program that,
after being initially loaded into the computer,
manages all the other programs in a
computer.
• It acts as an interface between user and the
hardware.
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Operating system
• The application programs make use of the
operating system by making requests for
services through a defined application
program interface (API).
• Users can interact directly with the operating
system through a user interface such as a
command line or a graphical user interface
(GUI).
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Objectives/importance of OS
• Convenience:
– The primary objective of an OS is convenience for users. It
executes users programs and make it easy to solve users
problems. It also make computer system convenient to
use.
• Efficiency:
– Efficient operation of computer system is the responsibility
of OS. It is important for large, shared multi user system.
OS provides the facility to use the hardware in an efficient
manner.
• Ability to evolve (grow)
– OS provides development and introduction of new system
functions and development of new softwares.
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Functions of OS
• An operating system is the main controller of a
computer system, therefore it provides a
variety of functions to the computer and its
users.
– Process management
– Memory management
– File management
– I/O system management
– Secondary storage management
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1. Process management
• A program under execution is called process.
• Process management is that function of OS in
which it deals with running multiple processes
on a single processor.
• If there are more processes to run on a single
processor then the OS decides which process
should be assigned to the CPU for how much
time.
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2. Memory management
• Computer memory should be properly
managed.
• Memory is grouped into registers, cache
memory, RAM, secondary memory.
• Memory manager is responsible for the
coordination of these types of memories.
• Which memory is available, which memory is
to be allocated or de allocated and how to
move data among them.
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3. File management
• The data is stored in
computer memory in
files which are further
arranged in sub
directories and root
directory resulting in a
hierarchal file system.
• File manager keep track
of all these files and the
whole process is called
file management.
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4. I/O management
• Every computer has I/O system such as
monitor, keyboard, mouse, printer etc. all
these devices need proper management.
• I/O manager or device manager and the
process is called I/O system management.
• For using audio and video hardware device
drivers need to be installed.
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5. Secondary storage management
• Those devices which store data permanently
are called secondary storage devices like HDD,
CD, USB etc.
• OS manages secondary storage devices and
handle proper flow of data among primary
and secondary storage devices.
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Network
Elements of network
Types of network
Internet
WWW
Email

Network
• When we connect two or more computers for
sharing data and resources, is called a
network.
98

Network
• A computer network is a series of points or nodes,
interconnected by communication paths for the
purpose of transmitting, receiving and exchanging
data.
• Network devices including switches and routers are
used to exchange information and to transport data
to endpoints.
• Every endpoint in a network has a unique identifier
called IP address that is used to indicate the source or
destination of the transmission. Endpoints can include
servers, personal computers, phones and many types
of network hardware.
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Elements of a network
• Basic elements of a computer network
include:
– Network devices
– Software
– Protocols
– Connection medium
– Client devices
• The interrelationship of these basic elements
constitutes the infrastructure of the network.
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Elements of Computer Network
• Network devices:
– The backbone of any network is the hardware that
runs it. Network hardware includes network cards,
routers, switches, modems, repeaters etc.
• Software:
– software that instructs network devices how to
connect to the network and how to interact with one
another.
• Protocols:
– Set of rules that governs data communication from
one device to another.
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Elements of a network
• Connection medium:
– The medium used to connect the network devices.
Wired networks will often use network cables
while wireless networks make direct connections
between devices using radio signals as the
medium.
• Client devices:
– Client devices are the computers and mobile
devices connected to the network.
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Types of network
• Local Area Network (LAN):
– The computers are geographically close together
(that is, in the same building).
• Metropolitan Area Network MAN):
– A data network designed for a town or city.
• Wide Area Networks (WAN):
– The computers are farther apart and are
connected by telephone lines or radio waves.
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LAN
• Local area network is a group of computers connected with each
other in a small places such as school, hospital, apartment etc.
• LAN is secure because there is no outside connection with the local
area network thus the data which is shared is safe on the local area
network and can’t be accessed outside.
• LAN due to their small size are considerably faster, their speed can
range anywhere from 100 to 100Mbps.
• LANs are not limited to wire connection, there is a new evolution to
the LANs that allows local area network to work on a wireless
connection.
104

MAN
• MAN network covers larger area by connecting
LANs to a larger network of computers.
• In Metropolitan area network various Local area
networks are connected with each other through
telephone lines.
• The size of the Metropolitan area network is
larger than LANs and smaller than WANs(wide
area networks), a MANs covers the larger area of
a city or town.
105

WAN
• Wide area network provides long distance
transmission of data. The size of the WAN is
larger than LAN and MAN.
• A WAN can cover country, continent or even a
whole world. Internet connection is an example
of WAN.
• Other examples of WAN are mobile broadband
connections such as 3G, 4G etc.
106

Network Topology
• The layout pattern using
which devices are
interconnected is called
as network topology.
Such as Bus, Star, Mesh,
Ring.
107

Introduction to internet
• The Internet is a global system of
interconnected computer networks. It is
a network of networks that consists of millions
of private, public, academic, business, and
government networks.
108

Internet
• The Internet is named for interconnection of
computer networks. It is a massive hardware
combination of millions of personal, business,
and governmental computers, all connected
like roads and highways.
109

History of internet
• The Internet started in the 1960's under the
original name ARPAnet. ARPAnet was
originally an experiment in how the US
military could maintain communications in
case of a possible nuclear strike. With time,
ARPAnet became a civilian experiment,
connecting university mainframe computers
for academic purposes.
110

History of internet
• As personal computers became more famous
in the 1980's and 1990's, the Internet grew
exponentially as more users plugged their
computers into the massive network. Today,
the Internet has grown into a public
spiderweb of millions of computers, all
connected by cables and by wireless signals.
111

Who owns the internet?
• No single person owns the Internet. No single
government has authority over its operations.
Some technical rules and hardware/software
standards enforce how people plug into the
Internet, but for the most part, the Internet is
a free and open broadcast medium of
hardware networking.
112

World wide web (www)
• The World Wide Web also known as the web,
WWW or W3 refers to all the public websites or
pages that users can access on their local
computers and other devices through
the internet. With a web browser, one can
view web pages that may contain text, images,
videos, and other multimedia.
• The Web is viewed by using free software called
web browsers.
• There are billions of web-pages on the web.
113

What is URL?
• Web sites are found by their addresses on the
World Wide Web. These addresses are known as
URLs or Uniform Resource Locators. Every web
site has a URL assigned to it, so both searchers
and Web servers can find them quickly and easily.
• Example
• http://www.google.com
• http://www.facebook.com
• http://www.yahoo.com
114

What are Applications of Internet?
• Communication
• Job Search
• Online Shopping
• Web Browsing
• Research
• E-Commerce
• Online Payments
• Social Networking
• Education
• Entertainment
115

1. Communication
• Internet is used for
communication purposes.
• Some popular internet
Communication
applications are:
– Email
– Skype
– Google Meet
– Zoom
– WhatsApp
– Facebook Messenger
116

2. JOB search
• In today's digital world it is
very easy to find the job of
your choice.
• Today you can easily find
jobs related to your skills
through the internet and
give a direct interview
online.
– Naukri.com
– Monster.com
– Freshersworld.com
– Indeed.com
– Glassdoor
– ZipRecruiter
117

3. Online shopping
• Today the whole world is
doing online shopping
through the internet, sitting
at home and you can also
shop online from home
through the internet.
– Amazon
– FlipKart
– Paytm Mall
– ShopClues
– Myntra
– Snapdeal
– Meesho
118

4. Web Browsing
• Searching the internet
with the help of a web
browser is called web
browsing or web
searching.
• Some famous web
browsers are:
– Internet Explorer.
– Google Chrome.
– Mozilla Firefox.
– Safari.
– Opera.
119

5. Research
• Internet helps
researchers to make
their work easy. They
can search about topics
online about their
research.
• They can access
thousands of research
papers with the help of
internet.
120

6. E-Commerce
• E-commerce means putting
your shop online and selling
any of your items online. By
doing this, your business
becomes local to global,
that is, you can sell your
goods to the people of
other cities as well.
– Amazon
– Flipkart
– Meesho
– Shopify
– Paytm Mall
– Dukaan
121

7. Online Payment
• In today's digital age,
now everyone is paying
any bill online instead
of giving cash.
• You can pay any bill
through an online
payment.
– Easypaisa
– Jazzcash
– Paypall
– Google pay etc
122

8. Social networking
• Social networking is also a
good platform, through which
you talk to people. Today
millions of people around the
world are using social
networking sites. Through
social networking sites, you
can make connections with
friends, family, classmates,
customers, and clients.
– Facebook
– Instagram
– Twitter
– LinkedIn
– YouTube
123

9. Education/E-learning
• Today is the era of e-
learning in the present
time, e-learning means
electronic learning which
means you can now study
from anywhere through
e-learning.
– Byjus
– Topper
– Vedantu
– Unacademy
– Quick Learn Computer
124

10. Entertainment
• Today there are many
such internet
applications that can
entertain you. You can
watch anything on
these entertainment
applications. Like -
Movies, Web series,
Cartoons, Serials,
Cricket, News, Comedy,
etc.
125

Email
• Short for electronic mail.
• e-mail or email is information stored on a
computer that is exchanged between two
users over telecommunications.
• More simply e-mail is a message that may
contain text, files, images, or other
attachments sent through a network to a
person or group of persons
126

Email address
• An email address is a unique identifier for an
email account. It is used to both send and
receive email messages over the Internet.
Similar to physical mail, an email message
requires an address for both the sender and
recipient in order to be sent successfully.
127

Email address
• Every email address has two main parts: a
username and domain name. The username
comes first, followed by an at (@) symbol,
followed by the domain name. In the example
below, "mail" is the username and
"techterms.com" is the domain name.
alibaba@gmail.com
128

Email providers
• Gmail
• Yahoo mail
• Hotmail
• Ymail
• Outlook etc.
129

Computer security threats
• Computer Security Threats are possible
dangers that can affect the smooth
functioning of your PC.
• These may be a small piece of adware or a
harmful Trojan malware.
• In the present age, computer security threats
are constantly increasing as the world is going
digital.
130

Types of Threats
• There are two types of computer threats
– Physical threats
• Internal
• External
• human
– Non physical threats
• Malware
• Virus
• Spyware
• Worms
• Trojan
• DoS attacks
• Phishing
• Key-loggers
131

Physical Threats
• A physical danger to computer systems can be an
event that could result in data loss or physical
damage. It can be classified as:
– Internal: Short circuit, fire, non-stable supply of
power, hardware failure due to excess humidity, etc.
cause it.
– External: Disasters such as floods, earthquakes,
landscapes, etc. cause it.
– Human: Destroying of infrastructure, hardware, thefts
and unintentional/intentional errors are among the
threats.
132

Non-physical threats
• A non-physical threat is a possible source of an
incident that could result in:
– Slow down the business operations that depend on
computer systems.
– Sensitive – data or information loss
– Keeping track of other’s computer system activities
illegally.
– Hacking id & passwords of the users, etc.
• The non-physical threads can be commonly
caused by:
133

Non-physical threats
• Malware:
– Malware, short for “malicious software,” refers
to any intrusive software to steal data and
damage or destroy computers and computer
systems. You may notice that your system is
processing at a slower rate than usual.
– Examples of common malware include viruses,
worms, Trojan viruses, spyware, adware, and
ransomware.
134

• Virus:
– It is a program that replicates itself and infects
your computer’s files and programs and make
them inoperable.
– It is a type of malware that spreads by inserting a
copy of itself and become a part of another
program.
– It spreads with the help of software or
documents.
135

• Worms:
– Computer worms are similar to viruses in that
they replicate themselves and can inflict similar
damage.
– Worms do not require a host program or human
assistance to spread.
– Worms don’t change programs they replicate
themselves over and over.
– They just eat resources to make the system down.
136

• Spyware:
– Spyware is a type of computer program that
tracks, records, and reports a user’s activity
(offline and online) without their permission for
the purpose of profit or data theft.
– Sources: websites, email, chat
– Example: adware
137

• Trojan:
– A Trojan horse is malicious software that is
disguised (masked) as a useful host program.
When the host program is run, the Trojan
performs a harmful/unwanted action
– It appears to be legal yet has the ability to take
control of your computer.
– It is designed to disrupt, steal or harm your data
or network.
138

• Denial Of Service Attacks:
– A Denial of Service attack is one in which an
attacker tries to prohibit (stop) legal users from
obtaining information or services.
– An attacker tries to make a system or network
resource unavailable to its users.
– The web servers of large organizations such as
banking, commerce, trading organizations, etc. are
the victims.
139

• Phishing:
– Phishing is a type of attack that is frequently used
to obtain sensitive information from users, such as
login credentials and credit card details by sending
spam, malicious Web sites, email messages, and
instant chats.
140

• Key-Loggers:
– Keyloggers can monitor a user’s computer activity
in real-time. Keylogger is a program that runs in
the background and records every keystroke made
by a user, then sends the data to a hacker with the
intent of stealing passwords and financial
information.
141

How to make your system secure?
• Always keep a backup of your data.
• Install firewall software and keep it updated every
time.
• Make use of strong and difficult to crack passwords
• Install antivirus and keep it updated every time.
• Timely scan your complete system.
• Before installing any program, check whether it is safe
to install it.
• Take extra caution when reading emails that contain
attachments.
• Always keep your system updated.
142

Database
• A database is a shared collection of
logically related data designed to meet
the requirements of different users of an
organization.
143

Database Approach
144
Registration
Examination
Library
Applications
Library
Examination
Applications
Registration
Applications
University
Students
Database
Database Management System

Characteristics of Relational Database
• Information is stored in the form of tables.
• A table contains rows and columns.
• Primary keys are used for unique identification
of rows.
• Foreign keys are used to link tables.
• SQL is used for data access.
145

Number system
• A number system is a term used for a set of
different symbols or digits which represents a
numerical value.
• Following are four commonly used number
systems.
– Decimal number system
– Binary number system
– Octal number system
– Hexadecimal number system
146

Decimal number system
• The most popular and commonly used
number system is the decimal number system.
Also called natural number system because it
is used by humans.
• It is composed of ten symbols or digits and
hence it is called decimal system.
• It is also called base-10 number system.
• 0 1 2 3 4 5 6 7 8 9
• 0 is the smallest and 9 is the largest value.
147

Decimal number system
• (345)10 means 3x102 +4x101 + 5x100
• 300+40+5=345
• 3 is the most significant digit
• 5 is the least significant digit.
148

Binary number system
• Binary number system comprising of two digits as binary
means two.
• In binary number system there are only two values 0 and 1.
• The base of binary number system is 2, base-2
• It is a natural number system for hardware.
• 0 represents the off and 1 represents the on state of the
circuit.
• The leftmost binary digit is the most significant bit (MSB)
while the rightmost digit is the least significant bit (LSB).
• 10001101
149

Octal number system.
• Octal means eight
• So octal number system consists of 8 digits 0-7
• 0 1 2 3 4 5 6 7
• The base of this system is 8, base-8
• Each digit or symbol determines its value in
the power of 8.
150

Hexadecimal number system
• Hexa means 16.
• Hexadecimal number system consist of 16
digits.
• 0 1 2 3 4 5 6 7 8 9 A B C D E F
• Consist of numbers from 0-9 and alphabets
from A-F.
151

• Inter-conversion of number system is not
included in these notes
153

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