FUNDAMENTALS OF INFORMATION

TECHNOLOGY

UNIT I
What is a Computer?

Definition1: Computer is an Electronic Device which performs the Arithmetic

and Logical operations.

(or)

Definition2: Computer is an Electronic Device which accepts the input from

the user , processing it and produce the output to the user.

Characteristics of a Computer
1.Speed: – As you know computer can work very fast. It takes only few
seconds for

calculations that we take hours to complete. computer can perform millions

(1,000,000)

of instructions per second. Therefore, we determine the speed of computer in

terms of milliseconds, microseconds, nanoseconds and pico seconds.

2. Accuracy: – The degree of accuracy of computer is very high and every

calculation is

performed with the same accuracy. The errors in computer are due to human
technological weaknesses.

3. Diligence: – A computer is free from tiredness, lack of concentration etc. It

can work
for hours without creating any error. If millions of calculations are to be
performed, a

computer will perform every calculation with the same accuracy.

4. Versatility: – It means the capacity to perform completely different types

of work. You

may use your computer to prepare payroll slips. Next moment you may use it
for

inventory management or to prepare electric bills.

5. Power of Remembering: – Computer has the power of storing any

amount of information . Any information can be stored and recalled as long as
you require it, for

any numbers of years. It depends entirely upon you how much data you want
to store in

a computer and when to lose or retrieve these data.

6. No IQ: – Computer is an electronic machine and it cannot do any work

without

instruction from the user. It performs the instructions at tremendous speed

and with

accuracy which is given by the user. So a computer cannot take its own
decisions as you

can.

7. No Feeling: – It does not have feelings or emotion, taste, knowledge and

experience.

Thus it does not get tired even after long hours of work.

Limitations of a Computer
Following are some of the limitations of a computer.

 Lack of common-sense
 No IQ
 No Feeling
 Computers can’t Decide
 Computers can’t Express their Ideas
 Computers can’t Implement
 Computers can’t Think
 Depend on the user input.
 No Learning Power
 An expert user can work on a computer

Applications of a Computer
Computers play a role in every field of life. They are used in homes,
business, educational institutions, research organizations, medical field,
government offices, entertainment, etc.

Home

Computers are used at homes for several purposes like online bill payment,
watching movies or shows at home, home tutoring, social media access,
playing games, internet access, etc. They provide communication through
electronic mail. They help to avail work from home facility for corporate
employees.

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 delicate operations, and conduct surgeries
remotely. It also helps to monitor the fetus inside the mother’s womb.

Entertainment

Computers help to watch movies online, play games online; act as a virtual
entertainer in playing games, listening to music, etc. MIDI instruments greatly
help people in the entertainment industry in recording music. Videos can be
fed from computers to full screen televisions. Photo editors are available with
fabulous features.

Industry

Computers are used to perform several tasks in industries like managing

inventory, designing purpose, creating virtual sample products, interior
designing, video conferencing, etc. Online marketing has seen a great
revolution in its ability to sell various

products to inaccessible corners like interior or rural areas. Stock markets

have seen phenomenal participation from different levels of people through
the use of computers.

Education

Computers are used in education sector through online classes, online

examinations, referring e-books, online tutoring, etc. They help in increased
use of audio-visual aids in the education field.

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 benefited from computers in their use for
missile development, satellites, rocket launches, etc.

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.
Banks have reduced manual errors and expenses to a great extent through
extensive use of computers.

Business

Nowadays, computers are totally integrated into business. The main objective
of business is transaction processing, which involves transactions with
suppliers, employees or customers. Computers can make these transactions
easy and accurate. People can analyze investments, sales, expenses, markets
and other aspects of business using computers.

Training

Many organizations use computer-based training to train their employees, to

save money and improve performance. Video conferencing through computers
allows saving of time and travelling costs by being able to connect people in
various locations.

Arts

Computers are extensively used in dance, photography, arts and culture. The
fluid movement of dance can be shown live via animation. Photos can be
digitized using computers.

Science and Engineering

Computers with high performance are used to stimulate dynamic process in

Science and Engineering. Super computers have numerous applications in
area of Research and Development (R&D). Scientists use computers to plot
and analyze data to have a better understanding of earthquakes.

Block Diagram of a Computer

A block diagram of a computer displays a structural representation of a
computer system.

A computer system is a combination of three components.

 Input Unit
 CPU(Central Processing Unit)
 Output Unit

Input Unit

All the data received by the computer goes through the input unit. The
input unit comprises different devices. Like a mouse, keyboard, scanner,
etc. In other words, each of these devices acts as a mediator between the
users and the computer.
The data that is to be processed is put through the input unit. The
computer accepts the raw data in binary form. It then processes the data,
and produces the desired output.

CPU(Central Processing Unit)

Central Processing Unit or CPU, is the brain of the computer. It works

the same way a human brain works. As the brain controls all human
activities, the CPU too controls all tasks.

Now the CPU comprises of three units, namely – ALU (Arithmetic Logic
Unit), CU (Control Unit) and MU (Memory Unit)

ALU(Arithmetic Logic Unit)

The Arithmetic Logic Unit is made of two terms, arithmetic and logic.
There are two major functions that this unit performs.

1. Data inserted through the input unit into the primary memory. Then It
sends the data into the ALU. It Performs the basic arithmetical
operation on it. Like addition, subtraction, multiplication, and division.
It performs all sorts of calculations required on the data. Then sends
back data to the memory.
2. The unit is also responsible for performing logical operations like, AND,
OR, Equal to, Less than, etc.

CU(Control Unit)

The control unit as the name suggests is the controller of all the
activities/tasks and operations. All this is performed inside the
computer.
It also controls all devices such as memory, input/output devices
connected to the CPU.

MU(Memory Unit)
Memory Unit is an essential part of computer system which is used
to store data and instructions before and after processing. The Memory
Unit transmits the information to other units of computer system
whenever required.

There are Two types of Memory Units.

1) Primary Memory
2) Secondary Memory

1) Primary Memory
The Primary Memory cannot store a vast amount of data. The data
stored in the Primary Memory is temporary. The data will be lost when the
power is not supplied. The Primary Memory is also known as Main
Memory or Temporary Memory. Random Access Memory(RAM) is
an example of Primary Memory.

2) Secondary Memory

The use of Primary Memory is not possible to store the data

permanently for future access. Therefore, there are some other options to
store the data permanently for future use, which is known as Secondary
Memory or Auxiliary Memory or Permanent Memory.

Output Unit
 All the information sent to the computer once processed is received
by the user through the output unit. Devices like printers, monitors,
projector, etc. all come under the output unit.

The output unit displays the data either in the form of a soft copy or
hard copy.

I / O devices

Input Devices

Following are some of the important input devices which are used
in a computer −

 Keyboard
 Mouse
 Joy Stick
 Light pen
 Track Ball
 Scanner
 Microphone
 Magnetic Ink Card Reader(MICR)
 Optical Character Recognition(OCR)
 Bar Code Reader

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.

The keys on the keyboard are as follows −

S.N Keys & Description

o

Alphanumeric Keys
1
These keys include the letter keys (A-Z) and digit keys (0-
9)

Function Keys

The Twelve function keys are present on the keyboard

2
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.

Control keys

These keys provide cursor and screen control. It

4
includes four directional arrow keys. Control keys also
include Home, End, Insert, Delete, Page Up, Page
Down, Control(Ctrl), Alternate(Alt), Escape(Esc).

5 Special Purpose Keys

 Keyboard also contains some special purpose keys such
as Enter, Shift, Caps Lock, Num Lock, Space bar,
Tab, and Print Screen.

Mouse

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,
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. A mouse can be used to control
the position of the cursor on the screen, but it cannot be used to enter
text into the computer.

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.

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.

Track Ball

Track ball is an input device that is mostly used in notebook or laptop

computer, instead of a mouse. This is a ball which is half inserted and by
moving fingers on the ball, the pointer can be moved.
Since the whole device is not moved, a track ball requires less space than
a mouse. A track ball comes in various shapes like a ball, a button, or a
square.

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.

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 or for mixing music.

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.

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.

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
labelling 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.

Output Devices

Following are some of the important output devices used in a computer.

 Monitors
 Graphic Plotter
 Printer
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
Cathode-Ray Tube (CRT) Monitor

The CRT display is made up of small picture elements called pixels. The
smaller the pixels, the better the image clarity or resolution.

A finite number of characters can be displayed on a screen at once. The

screen can be divided into a series of character boxes - fixed location on
the screen where a standard character can be placed. Most screens are
capable of displaying 80 characters of data.

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 or wear them on your wrists. Current uses of flat-panel
displays include calculators, video games, monitors, laptop computer, and
graphics display.

Printers

Printer is an output device, which is used to print information on paper.

There are two types of printers −

 Impact Printers
 Non-Impact Printers

Impact Printers

Impact printers print the characters by striking them on the ribbon, which
is then pressed on the paper.

These printers are of two types −

 Character printers
 Line printers
Character Printers
Character printers are the printers which print one character at a time.
These are further divided into two types:
 Dot Matrix Printer(DMP)
 Daisy Wheel
Line Printers
Line printers are the printers which print one line at a time.

These are of two types −

 Drum Printer
 Chain Printer
Non-impact Printers

Non-impact printers print the characters without using the ribbon. These
printers print a complete page at a time, thus they are also called as Page
Printers.

These printers are of two types −

 Laser Printers
 Inkjet Printers

Plotters

Plotters are a special type of output device.

It is suitable for applications:

1. Architectural plan of the building.

2. CAD applications like the design of mechanical components of
aircraft.
3. Many engineering applications.

Speakers:

 Speakers are used to connect to a computer to generate

sound, which are one of the most common output devices.
 Some speakers are designed to connect with any kind of sound
system, while some can be hooked up only with computers.
 With the computer speaker, the computer's sound card creates a
signal that is used to produce sound.
 The primary objective of speakers is to offer audio output for the
listener.

Generations of a Computer
Generation in computer terminology is a change in technology a computer
is/was being used.

S.N Generation & Description

o
1 First Generation
The period of first generation: 1946-1959. Vacuum tube based.
2 Second Generation
The period of second generation: 1959-1965. Transistor based.
3 Third Generation
The period of third generation: 1965-1971. Integrated Circuit
based.
4 Fourth Generation
The period of fourth generation: 1971-1980. VLSI microprocessor
based.
5 Fifth Generation
The period of fifth generation: 1980-onwards. ULSI
microprocessor based.

First Generation(1946-1959)

The period of first generation was from 1946-1959. The computers

of first generation used vacuum tubes as the basic components for
memory. These tubes, like electric bulbs, produced a lot of heat.
Therefore, they were very expensive and only large organizations were
able to afford it.

In this generation, mainly batch processing operating system was

used. Punch cards, paper tape, and magnetic tape was used as input and
output devices. The computers in this generation used machine code as
the programming language.