This document provides an introduction to computers, including how they work and their key characteristics. It defines a computer as an electronic device that accepts input, processes data, stores data, and produces output. It then describes the main components of a computer and how data is processed. The document outlines the main characteristics of computers as being fast, accurate, having large memory and storage, being diligent and versatile. It also categorizes the different types of computers as analog, digital, and hybrid and provides examples of each type. Finally, it classifies computers as microcomputers, minicomputers, mainframes, and supercomputers and describes the defining features of each.

1. Introduction To
Computer
By:
Prabesh Shrestha

2. Introduction
¤ Its an electronic device which accepts
input, processes data, stores data,
and produces output
¤ Input refer to whatever is sent to a
Computer system
¤ Data refer to the symbols that
represent facts, objects, and ideas
¤ A computer processes data in a device
called the central processing unit
(CPU)

3. How Computer Works

4. Definition
• Computer can be defined as “An electronic
and electromechanical device”
• It intakes raw data, manipulates it and
gives accurate output in the form of
information.

5. Characteristics of Computer
Main characteristics of the computer can be
summarized as:
1. Speed: Computer is very fast and accurate
device. It can process millions and millions of
instructions within seconds.
2. Accuracy: Computer results are highly accurate.
3. Memory: Computers have a large amount of
memory to hold a very large amount of data or
information.

6. 4. Diligence: Computer is free from
problems like lack of concentration,
and confusions & tiredness.
5. Versatility: We can perform
different types of tasks on computer.
It is therefore versatile in nature.
6. Power of Remembrance: Unlike
humans, computer can store things
for unlimited period of time.

7. Types of Computer
There are two basic kinds of computers:
• Analog Computer
• Digital Computer
• Hybrid computer

8. Analog computers
 Analog computers are analog devices.
That is, they have continuous states
rather than discrete numbered
states.
 An analog computer can represent
fractional values exactly, with no
round off.
 They handle or process information,
which is of physical nature.
 Examples: Computers in Chemical
plants monitoring temperatures,
pressures, voltage, etc.
Now these days, we rarely came across of analog
computers in routine life.

9. Digital Computer
 A digital computer uses discrete
states.
 A binary digital computer uses
digits and process data, which is
essentially in a binary state.
 Example: Personal Computers,
scientific calculators, etc.

10. Hybrid Computer
 It refers to computer that contain
both digital and analog circuit.
 For Example: A digital
thermometer converts the
temperature (analog signals) and
gives the output of measurement in
digits (digital signal)

11. Classification of Computer
• Micro Computer
• Mini Computer
• Mainframe Computer
• Super Computer

12. Micro Computer
 Micro computer is general purpose
computer, it is also called Personal
Computer (PC).
 It uses microprocessor, CPU for
manipulating data.
 It is smaller than Mini Computer,
Mainframe Computer and Super
computer.
 It has storage capacity up to Terabytes
(TB)
 It is used in general purpose.
 Example: IBM PC, Apple Macintosh,
Sony VAIO, etc.

13. Mini Computer
• Mini computer is smaller than
Mainframe and Large than micro
computers.
• It is cheap than mainframe
computers.
• It has storage capacity less than
micro computers.
• Examples: Data General, Wang
Laboratories, Apollo Computer,
and Prime Computer.

14. Mainframe Computers
 Mainframe Computers are very
powerful large-scale general-
purpose computers.
 It’s memory capacity is in
megabytes (MB) and storage
capacity is in terabytes (TB).
 They are used where large amount
of data are to be processed.
 Examples are: IBM 4300 series, IBM
Enterprise, System/9000 series

15. Super computer
 A supercomputer is a computer
which has high processing
capacity – particularly speed of
calculation.
 It has high storage capacity in
Petabyte (PB).
 It has number of CPUs to make
more speed.
 Example: IBM roadrunner, Cray
Jaguar, Cray Titan, IBM Sequoia,
etc.

16. Advantages & Disadvantages of Computer
Advantages
• It makes our work easier,
faster and accurate.
• It saves our cost and time
while collecting,
manipulating and storing
large amount of data
• It helps in worldwide
communication.
Disadvantages
• It is harmful to health, it
affects eyesight and
backbones if we work too
long.
• It creates unemployment.
• It makes people dumb and
dull.

17. The
End