INTRODUCTION TO
COMPUTER
COMPUTER
The word computer comes from the “compute”, which
means, “ to Calculate”
oThereby, computer is an electric device that accepts data
from user, process the data and generates the output result.
Computer performs both simple and complex task with speed
and accuracy.
CHARACTERISTICS OF COMPUTERS
Speed: Computer can perform data processing jobs very fast, usually
measured in microseconds, nanoseconds and picoseconds.
Accuracy: Accuracy of a computer is very high. The degree of its
accuracy depends upon its design. Computers errors caused due to
incorrect input data or incorrect programs.
Diligence: Computer is free from monotony, tiredness. It can
continuously work for hours without creating any error.
Power of Remembering: computers can store and recall any amount of
information because of its storage capability.
No I. Q: A computer does only what it is programmed to do. It cannot
takes its own decision in this regard.
THE DIFFERENT PARTS OF A COMPUTER
SYSTEM
A complete computer system consists of four parts:
Hardware
Software
Data
Users
THE DIFFERENT PARTS OF A COMPUTER
SYSTEM
Hardware: It consists of the mechanical parts that make up the compute as a
machine. The hardware consists of physical devices of the computer. Some
hardware devices are keyboard, monitor, hard disk drive, printer, processor and
motherboard etc.
Software: It is a set of instructions that tells the computer about the task to be
performed and how the task is to be performed. Software is also called program.
Program is a set of instructions, written in a language understood by the computer.
The hardware of the computer system can not perform any task on its own.
Software is the life of hardware. Software instructs the computer about the task to
be performed. Different software can be used on the same hardware to performed
different kinds of task.
Data: data are raw facts which by themselves may not
make much sense to a person. Computers process data in
various ways. Computers converting data into
information.
Users: users are people who write computer programs or
interact with the computer. They are also known as
liveware, humanware or peopleware. Programmers, data
entry operators, system analyst and computer hardware
engineers fall into this category.
APPLICATIONS OF COMPUTERS
Computers are used in various areas of our life.
Education, entertainment, sports, advertising, medicine,
science and engineering, government, office and home
are some of the application areas of the computers.
Education: computers are extensively used as a tool for
imparting education. Educators use computers to
prepare their lectures. Computers are used to provide
distance education using the e-learning software and to
conduct online examinations. Researchers use computers
to get access to the research materials.
Entertainment: computers have had a major impact on
the entertainment industry. The user can download and
view movies, play games, book tickets for cinema. The
user can also listen music, share and create music by
using computers.
Sports: a computer can be used to watch a game, view
the scores and play games such as Chess etc.
Business: today’s companies perform basic functions by
using computers such as daily accounting activities,
payroll, inventory management etc. Today’s banks can
not exist without computer technology.
Health care: Computers are making health care more
efficient and accurate. The medical history of patients is
stored in the computers. Computers are also an essential
part of various kinds of sophisticated medical equipments
such as ultrasound machine, MRI machine etc.
Government: the government use computers to mange its
own operations and for e- governance. The websites of
different government departments provide information to
the citizens.
Home: computers have now an essential part of home
equipment. At home, people use computers to
communicate, to play games, to operate small home based
business and so on.
THE INPUT-PROCESS-OUTPUT
CONCEPT
A computer is an electronic device that
(1) accepts data,
(2) processes data,
(3) generates output,
(4) stores data.
This is also referred to as input-process-output concept.
The input-process-output concept of the computer is
explained as follows—
Input :The computer accepts input data from the user via an
input device like keyboard. The input data can be
characters, word, text, sound, images, document, etc.
Process: The computer processes the input data. For this, it
performs some actions on the data by using the instructions
or program given by the user of the data. The action could
be an arithmetic or logic calculation, editing, modifying a
document, etc.
Output: The output is the result generated after the
processing of data. The output may be in the form of
text, sound, image, document, etc. The computer may
display the output on a monitor, send output to the
printer for printing etc.
Storage The input data, instructions and output are stored
permanently in the secondary storage devices like disk.
COMPONENTS OF COMPUTER
HARDWARE
The computer system hardware consists of three main
components:
Input/output Unit
Central processing unit
Memory unit
Input/ output Unit: the user interact with the computers via
I/O unit. The input unit accepts data from the users and the
output unit provides information to the users. The input unit
converts data into a form that is understandable by the
computer. Similarly, output unit provides the output in a form
that is understandable by the user. The input is provided to
the computer by using input devices such a keyboard, mouse
etc. the most popular output devices are monitor and printer.
Central Processing Unit: CPU controls, coordinates
and supervises the operations of the computer. It is
responsible for processing of the input data. CPU
consists of Arithmetic Logic Unit (ALU) and Control
Unit (CU).
ALU performs all the arithmetic and logic operations on the
input data.
CU controls the overall operations of the computer.
Memory Unit: Memory unit stores the data,
instructions/program, intermediate results and output,
temporarily, during the processing of data. This memory
is also called the main memory or primary memory of
the computer.
Another kind of storage unit is also referred to as the
secondary memory of the computer. The data, the
programs and the output are stored permanently in the
storage unit of the computer. Magnetic disks, optical
disks and magnetic tapes are examples of secondary
memory.
CLASSIFICATION OF COMPUTER
The digital computers that are available nowadays vary
in their sizes and types. The computers are broadly
classified into four categories based on their size and
type—
(1)Microcomputers,
(2) Minicomputers,
(3) Mainframe computers, and
(4) Supercomputer.
Microcomputers:
Microcomputers are small, low-
cost and single-user digital
computer. They consist of CPU,
input unit, output unit, storage
unit and the software.
Microcomputers include desktop
computers, notebook computers
or laptop, tablet computer,
handheld computer, smart phones
and netbook.
Minicomputers: Minicomputers are digital computers,
generally used in multi-user systems. They have high
processing speed and high storage capacity than the
microcomputers. Minicomputers can support 4–200
users simultaneously. The users can access the
minicomputer through their PCs or terminal. Usually
used in industries, research centers, etc.
Mainframe computers: Mainframe computers are multi-user,
and high performance computers. They operate at a very high
speed, have very large storage capacity and can handle the
workload of many users.
The user accesses the mainframe computer via a terminal that
may be a dumb terminal, an intelligent terminal or a PC.
A dumb terminal cannot store data or do processing of
its own. It has the input and output device only.
An intelligent terminal has the input and output device,
can do some processing, but, cannot store data of its
own.
The dumb and the intelligent terminal use the processing
power and the storage facility of the mainframe
computer. Mainframe computers are used in
organizations like banks or companies.
Supercomputers: Supercomputers are the fastest and
the most expensive machines. They have high processing
speed compared to other computers. Some of the faster
supercomputers can perform trillions of calculations per
second. Supercomputers are used for highly calculation-
intensive tasks, such as, weather forecasting, climate
research (global warming), biological research, nuclear
research and aircraft design.
