01 Introduction to Pc

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Revision no.: PPT/2K403/02Revision no.: PPT/2K605/03

Introduction to PC


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Revision no.: PPT/2K605/03

CMS INSTITUTE, 2006. All rights reserved. No part of this material may be reproduced, stored or emailed without the prior permission of Programme Director, CMS Institute

General Concepts of Computers

A computer is a device that automatically performs arithmetic or

logical operations on information input to it and provides an output

according to the performed set of instructions stored within it. Hardware, Software and Firmware together make up a computer

system.

Hardware describes all the physical components used in theassembly of the computer.

Software constitutes the instructions on which the computer acts

which thus makes the computer usable.

Firmware are programs that are permanently written and stored in

computer memory.


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Terminologies of Computers

Computers understand only binary number system, which has

only two digits i.e. zero (0) and one (1).

A single binary digit is called BIT; the smallest unit ofrepresenting data in a computer.

A set of binary patterns include the letters (A - Z), decimal

digits (0 - 9), and certain special characters such aspunctuation marks are known as alphanumeric character set.

A group of 8 bits is called as one byte.

A group of 1024 bytes is called as one kilobyte(KB). A group of 1024 KB is called as one Megabyte(MB).


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Terminologies of Computers (contd.)

A group of 1024 MB is called as one Gigabyte(GB).

A computer's WORD is a group of bits, the length of which

varies from machine to machine.The word may be as long as64 bits or as short as 4 bits.


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Computers Architecture


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Functional Units

The basic structure of a computer is divided into 4

fundamental units.

CPU(Central Processing Unit)

Control Unit

Arithmetic Logic Unit (ALU)

Input Devices

Egs. Keyboard, Mouse etc.

Output Devices

Egs. Visual Display Unit(VDU), Printers, Plotters etc.

Storage Unit

Internal or Primary Storage

Egs. RAM and ROM

External or Secondary Storage

Egs. Floppy disks, Hard disks, Optical disks etc.


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Functional Working


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Software Basics

Computers work with instructions

which is the input given by humans

and this organized body of

instructions is called Software.

Software is needed to instruct

fundamental startup procedures like

data processing, word processing andimage processing.

Computers can understand only one

language called Machine Languagewhich includes a set of instruction

codes written as a string of bits.Also

known as 1st Generation Language.


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Software Basics (contd.)

The difficulties posed by the Machine Language led to the

development of the Assembly Language, also referred as 2nd

Generation Language.

Assembly Language is a direct translation of the machine

language code to understandable English type words however

it has to be translated back by the Assembler.

Due to the cryptic nature of Assembly Language, High-Level

Languages were developed such as C, BASIC, etc.

Next generation languages were result oriented and included

Database query languages which have to be compiled orinterpreted.

Fifth generation languages are intended to enable users to

communicate with computers using Natural Language.


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Classification of Software

Classified into two distinct groups

System Software

Application Software

System Software instruct the computer to control and manage

its internal functions, like initializing on start-up, controlling

external devices, organising the memory during operations

and many other activities. Eg. Windows 98

Application Software consists of programs which carry out the

specific processing required for user's application such as

Word Processor, Spread Sheets, and Financial Accounting ora computer-aided package.

Eg. MS Office, Tally, A-CAD etc.

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01 Introduction to Pc