Introduction to PC

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 the assembly 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.

What is Data?

Row Facts are known as Data. 

E.g. 77

What is Information?

Data which convey the meaning is called Information.

E.g. 77 Rs.

We all know that computer is an electronic device etc. But each alphabet has meaning, and what about the creator of the computer? who invent it ? when computer was invented ? what is the purpose to invent computer?

COMPUTER:

C = Commonly

O = Operated 

M = Machine 

P = Particularly 

U = Used

T = Trade

E = Education 

R = Research

Charles Babbage invented the first mechanical computer in the early 19th century, and the first personal computer was invented by Steve Wozniak ( partner of Steve Jobs ) invented the Apple I computer.

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 of

representing data in a computer.

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

digits (0 – 9), and certain special characters such as punctuation 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).

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 as 64 bits or as short as 4 

bits.

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

E.g. RAM and ROM

External or Secondary Storage

Eg. Floppy disks, Hard disks, Optical disks etc.

Software Basics

Computer work with instructions which is the input given by humans and this Software is needed to instruct fundamental startup procedures like data processing, word processing, and image processing.

Computer’s can understand only one language called Machine Language which includes a set of instruction codes written as a string of bits.Also known as 1st Generation Language

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 or interpreted.

Fifth generation languages are intended to enable users to communicate with computers using Natural Language.

Generation of Computer 

1st Generation : (1946 – 55 ) Vacuum Tubes

2nd Generation : ( 1956- 65 ) Transistor 

3rd Generation : ( 1966 – 75 ) IC’s ( Integrated Circuit )

4th Generation : ( 1976 -80 ) Microprocessor

5th Generation : ( 1980—– ) Advance Microprocessor 

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, organizing 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 or   a computer-aided package.

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