Online Services





A computer is an electronic device which can accept, store data and instructions (programs) and process data as directed by the given instructions and output the information (processed data) in the desired form at a great speed.

A computer consists the following:

I) Hardware II) Software III) Human ware

I) Hardware: The physical components which actually process data and produce output.

Hardware consists of the following components:

A) Input device b) CPU c) Output Device

A) Input Device: The device which is required to input data & instructions into the computer.


Keyboards, Mouse, Trackball And Space ball, Joysticks, Data Glove, Digitizers, Image Scanners, Touch Panels, Light Pens, Voice Systems, Etc

B) Central Processing Unit (CPU):A CPU Consists The Following:

Main Memory, Arithmetic & Logic Unit, Control Unit, Secondary Storage Device and Processor(S) On Motherboard and Also Its Communication Connections.

Main Memory: memory is a part in computer which holds data and instructions.

Arithmetic & Logic Unit (A.L.U):Computer should have a mechanism to make arithmetic calculations and logical comparisons of the given data.

Control Unit:A part which ensures that the instructions given are followed in the required sequence and also controls the other parts of the computer system such as A.L.U., memory, input and output devices.

Secondary Storage Device: these devices are used to storing data or information (text), instructions (programs), other kind of files(photos, audio, video, etc), etc for future use and help in their repeated use. These devices help in avoiding repeated operation of inputting data & instructions (programs) relating to the same problem.

C) Output Device: The device which is required to obtain the processed data and pass it to the user in required form.


Monitors (Screens), Printers, Sound Output Devices, Scanner (Act As Input As Well As Output), Web cam, Etc.

Memory, Arithmetic & Logic Unit And Control Unit Are Contained In One Unit Which Is Called "Central Processing Unit (C.P.U)".

The remaining devices such as input devices & output devices are called peripherals.

Hardware also consists of other kind of devices called secondary storage device.

II) Software:(without software hardware part of a computer is useless)

Hardware consists of only physical parts. Hardware parts of a computer cannot do anything on their own. They must be instructed to do work or solve a problem. Any work or a problem consists of data. Such data has be changed into required an useful form. Data required to solve a problem is called input. The method of converting the data into useful form is called processing. The result produced by processing the input is called output.

If we want to know or want to become expert in the computer field, then the words input, processing and output are basic terms used in understanding the subject of computers.

In order to make hardware part of a computer to solve a given problem, input data and the instructions to process such input data to produce a desired output should be given computer.

Instructions given to computer to make it ready for operation and to make use of the computer to solve problems are called software. Without software hardware part of a computer is useless.

Let assume, if we purchased a computer then that computer has only hardware parts no software. Hardware parts are Keyboard and Mouse (Input Devices), Monitor (Output Device) and CPU (Memory, Storage Devices (Hard Disk, Floppy Drive, CD-Rom Drive, etc)). Here this computer can’t be used because there is no software.

If we want to use this computer then we must have software on this computer system. Or we have to install software on this computer system.

But, Now-a-days Laptops/Desktop Systems are coming with in-built Operating System 

For that we must know about software.

What is Software:

Set of instructions (programs) given to computer to make it ready for operation and to make use of the computer to solve domains (problems) is called software.

Software consists of the programs of instructions and data that define for the hardware the algorithms for solving problems. Operating systems and other systems software are ordinarily supplied by hardware vendors. The vast majority of application software is supplied by independent software vendors (ISVS).

                       -Harvey M.Deitel (Boston College)
If we want to make the computer ready for use. Then we have to install operating system

What is an Operating System:

An operating system is a set of instructions (programs) which enable the computer to accept, process and output the information and control and coordinate the operations of all other devices connected to it are called operating system.

An operating system is a program that manages the computer hardware. It also provides a basis for application programs and acts as an intermediary between a user of a computer and the Computer Hardware.

-Peter b. Galvin

Mainframe operating systems are designed primarily to optimize utilization of hardware.

Personal Computer (PC) Operating Systems Support Complex Games, Business Applications and everything in between.

Handheld Computer Operating Systems are designed to provide an environment in which a user can easily interface with the computer to execute programs

The main purpose of an operating system is to provide an environment in which the user can execute programs.

Goals of operating system:

There are two goals. They are

I) Primary Goal: The Primary Goal of Operating System is to make the computer convenient to use.

II)Secondary Goal: The Secondary Goal is to use the Computer Hardware in an efficient manner.

After installing an operating system

High level language:

If we want to solve a problem then we must have special computer languages which enable the users (programmers or we(those who have basic knowledge of programming)) to prepare instructions to make use of computers for solving domains (problems) are called as high level languages.


C++, Java, COBOL, FORTRAN, Pascal, Small Talk, Ruby, Etc

Translator programs:

These are the instructions (programs) which are used to convert instructions in the high level languages to machine language which computers understand.


Assembler, Compiler, Interpretor, Linkers, Etc

Packages or Special Utility Programs:

These are special programs have been developed in High Level Languages which contain instructions (programs) for doing a particular type of processing by accepting data or other or etc. These kinds of programs are called as special utility programs or packages.


Ms-office, etc

III) Human ware :

Hardware and software are used by human beings (or we) who are specially trained in using them. Experts trained to different levels of technical skill of using computers are called Human ware.

A) System Analysts: The experts who can set up a whole system of computers and develop necessary software to fulfill a particular need of organizations (not only organizations, etc) are called systems analysts.

B) Programmers: The persons who assist systems analysts to develop programs required by a system and also develop programs independently to make use of computers are known as programmers.

C) Data Entry Personnel: The persons who just feed data and readymade programs to computers are data entry personnel.