What Is Computer?

What Is Computer?

What Is Computer? – A Computer is an electronic machine that accepts data from the user, processes the data by performing, calculations and operations on it and genrates the desired output as a result.

The term computer is derived from the Latin word ‘computare’ which means to ‘to compute

Generally, computer is the combination of Hardware and Software which converts data into information. Computer operates on set of instruction only, they cannot think as human being. Computer has an ability to store and execute set of instructions called program which makes it extremely distingushable and versatile than calculators. Computer makes people’s lives easier and more comfortable.

Function Of Computer

Computer Performs Four Basic Functions which are as follows:-

  1. Input – Information or data is entered into a computer called Input. Its sends data to the Central Processing Unit (CPU).
  2. Processing – It is the sequence of actions taken on data to convert it into information which is meaningful to the user. it can be calculations, comparisons or decisions taken by the computer.
  3. Output – It makes processed data available to the user. It is mainly used to display the desired result to the user as per input instructions.
  4. Storage – It stores data and programs permanently. It is used to store information during the time of program execution and possible to get any type of information from it.

Features Of Computer

The key features of computer are as follows:-

  1. Speed – The computer can process data very fast at the rate of millions of instructions per second.
  2. Accuracy – Computer provide are capable to store huge amount of data which depends on the capacity of hard disk.
  3. Storage Capacity – Computers are capable to store huge amount of data which depends on the capacity of hard disk.
  4. Versatile – Computers can do different types of work simultaneously. they can perform multiple tasks at a same time.
  5. Automatic – Once the instruction to do any work is given to the computer, the computer does its work automatically by itself.
  6. Diligency – Unlike human beings, a computer is free from monotony, tiredness, lack of concentrations, etc. and can work for hours without creating any errors.
  7. Secrecy – Leakage of information is reduced by creating login system with password protections.
  8. Reliability – Computer are more reliable than human beings. Computer always produce exact results. The possibility of errors occur only if the input is wrong. i.e computers never make mistakes of their own record.
  9. Plug and Play – Computers have the ability to automatically configure a new hardware and software component.

Terms Related To Computer

  1. Hardware – It is the collection of physical elements that constitute a computer system. It is a comprehensive term for all the physical parts of a computer e.g display screens, disks, keyboards etc.
  2. Software – It is a set of programs and proceducers. Software tells the hardware what to do and how to accomplish a task. eg. Web Browsers, Word processors. etc.
  3. Data – Unprocessed raw facts and figures, like numbers, text on pieces of paper, are knwon as data.
  4. Information – When data is processed, organized, structure or presented in a given context so as to be useful, then it is called information.
  5. Instruction – It is a command given to a computer in the computer language by the user.
  6. Program – It is a set of instructions given to a computer in order to performs some task.

History Of Computer

Computer is not the creation of one day, rather it took a long period for the development of modern computer. History of computer is described in this table.

Abacus – 1602ChinaFirst Mechanical Calculating Device
A horizontal rod represents the one, tens, hundread, etc.
Used for additions and substraction operations
Calculations of square roots can also be performed.
Napier’s Bones – 1617John NapierThree Dimensional Structure
Holding numbers from 0 to 9 only.
Represent graphical structure of calculating result.
Performs multiplication on numbers
Technology used for calculations called Rabdologia
Pascaline – 1642Blaise PascalFirst mechanical adding machine.
It was structured like rectangular box, with eight line disc (represent number of units)
Performs additions and substraction of two numbers.
Mainly designed with regard to the pressure of liquid.
Jacquard’s Loom – 1801Joseph Marie JacquardMainly weaved a silk based pattern.
Used punched card for the sequence of operations
Simplified the process of textiles
Analytical Engine – 1837Charles Babbage (Father of Computer)First general-purpose compute.
Stored program in the form of ‘pegs’ also called barels
it was a decimal machine used sign and magnitude for representation of a number.
Tabulating Machine – 1880Herman HollerithIt used punched cards with round holes.
It was the first electromechanical machine. designed to process the data for census in 1890.
Read one card at a time.
Mark -1 1944Howard AikenConsists of interlocking panels of small glass, counters, switches and control circuits
Data can be entered manually
Mainly used in the war effort during World War-II
Magnetic drums are used for storage
ENIAC – 1946JP Eckert and JW MauchlyIt is a combination of twenty accumalators.
First electronic digital computer
Used for weather prediction, atomic energy calculations and other scientific uses.
EDSAC 1949John Von Morris WilcusIt was first computer which provided storage capacity.
First computer program was run on machine
Capable of storing instructions and data in memory.
Used mercury delay lines for memory, vaccum tubes for logic.
UNIVAC – 1951Eckert John MauchlyFirst general-purpose electronic computer with large amount of input and output.Used magnetic tapes as input and output.
IBM-650 Computer 1954IBM CompanyProvided input/output units converting alphabetical and special characters to two-digit decimal codePayroll processing
Oil refinery design
Market research analysis

Generations Of Computer

A generations refers to the state of improvement in the development of system. Computers are built are electromechanical, before generations. Each generations of computer is characterised by a major technological development that fundamentally changed the way, computer operates.

GenerationsSwitching DeviceStorage DeviceSpeedOperating SystemLanguageCharacterticsApplications
First (1940-56)Vaccum TubesMagnetic Drums333 micro secondsBatch Operating SystemMachine Language (Binary number 0’s and 1’s)Fastest computing device
Generate large amount of heat.
Used for scientific purpose
e.g ENIAC, UNIV AC, MARK-1, etc.
Second (1956-63)Transistors (Made up of semiconductor)Magnetic Core Technology10 micro secondsTime sharing system, Multitasking OSAssembly language, high level languageMore reliable and less prone to hardware failure
Portable and generate less amount of heat.
Used for commercial production.
e.g PDP-8, IBM-1401, etc.
Third (1964-71)Integrated Circuits (ICs) (Made up of silicon)Magnetic Core as primary storage medium100 nano secondsReal-Time systemHigh Level Language
(Fortran, Cobol,Algol)
Consumed less power.
Highly sophisticated technology required
Database Management System
e.g NCR-395, B6500, etc.
Fourth (1971-Present)Large Scale Integrated (LSI)
circuit microprocessor
Semi Conductor memory, winchester disk300 nano secondsTime Sharing, GUI Interface.PASCAL, ADA, COBOL-74 FORTRON IVMore reliable and portable
This generations leads to better communication and resource sharing
Distributed system, e.g Intel 4004 chip, Macintosh.
(Present and Beyond)
Super Large Scale Integrated (SLSI) chipsOptical Disk—-Knowledge Information Processing System—–Parallel processing
Intel core microprocessor is implemented
Enables mega chips.
Artificial Intelligence e.g Robotics.


Siddhartha was the first computer developed in india.

Alan Turing is known as the father of modern computer.

John Von Neumann Was Introduced first architecture of computer in the year 1948.

Classications of Computer

Computers are mainly classified as three types as follows:

Based On Size

  • Microprocessor
  • Mainframe Computer
  • Minicomputer
  • Supercomputer

Based On Work

  • Analog Computer
  • Digital Computer
  • Hybrid Computer

Based On Purpose

  • General Purpose Computer
  • Special Purpose Computer

Based on Size

On the basis of size, computers are categorised as follows:


Microcomputers are the least powerful, yet the most widely used and fastest growing type of computers and are also called portable computers. Microcomputer consists of three basic categories of physical equipment, i.e system unit input/output unit and memory unit.

Some types of microcomputer are as follows:

(A) Desktop Computer or Personal Computer (PCs) – These are small, relatively inexpensive computers. These are based on the microprocessor technology (Integrated Circuit, IC). In 1958, Jack Kilby and Robert Noyce invented the first IC.

(B) Laptop – These computers are also known as Ultra Book or Notebook. These are portable, lightweight and fit into most briefcases. They include rechargabel battery, so these can work anywhere.

(C) HandHeld Computer – These are the smallest and are designed to fit into the palm. So these are also known as Palmtop. They are practical for certain functions such as phone books and calendars. They use the pen for input instead of computer.

(D) Tablet Computer – They have key features of the notebook computer, but these can accept input from a pen instead of the keyboard or mouse.

(E) Personal Digital Assistant – It is also knwon as a handheld PC, or personal data assistant, is a mobile device that functions as a personal information manager.


Minicomputers are smaller in size, faster, cost lower than mainframe computers. Initially, the minicomputers was designed to carry out some specific tasks, like engineering and Computer Aided Design (CAD) calculations. But Now, they are being used as central computer which is known as Server.

Minicomputers are IBM-17, DEC PDP-11, HP-9000, etc.

Mainframe Computer

Mainframe computers are those having large internal memory storage and comprehensive range of software. Mainframe computers serves as a backbone for the entire business world. It is considered as the heart of a network of computers or terminals that allows a large number of people to work at the same time. Mainframe computers are IBM-370, IBM-S/390, UNIAC-1110, etc.


Supercomputers are the fastest and most expensive machines. They have high processing speed compared to other computers. The speed of supercomputers are measured in FLOPS (Floating Point Operations Per Second).

Supercomputers are used for highly calculations intensive tasks, such as weather forecasting, nuclear research, military agencies and scientific research laboratories. Supercomputers are most powerful, large in size and memory, compared to all other computers.


CRAY-1 – It was the world’s first supercomputer introduced by Seymour R CRAY in 1976

PARAM – It Was first supercomputer developed in India in 1990

PARAM Kanchenjunga – It is the latest machine in the series of PARAM made by NIT (National Institute Of Technology) Sikkim 17th April 2016.

Tianhe-2 – It is the world’s fastest supercomputer launched by China at NUDT university in 2013. It Is based on Rylin Linux Operating System With 33.86 petaflops.

Based On Work

On the basis of work, computers are categorized as follows

Analog Computer

Analog computers are the job-oriented computers. They carry out arithmetic and logical operations by manipulating and processing of data. e.g speedometers, seismograph, etc. Analog computer can perform several mathematical operations simultaneoulsy. It uses continuous variables for mathematical operations and utilises mechanical or electrical energy.

Digital Computer

Digital computers work by calculating the binary digits. A digital computers, not only performs mathematical calculations. but also combines the bytes to produce desired graphics, sounds. e.g desktop (PC).

Hybrid Computer

Hybrid computers are the combinations of analog and digital computers. machines used in hospitals like BCG and DIALYSIS are the commonly used hybrid Computers.

Based on Purpose

On the basis of purpose, computers are categorized as follows

General Purpose Computer

General Purpose Computers are those computers, which are used to solve variety of problems by changing the program or instructions. e.g to make small database, calculations, accounting,etc.

Special Purpose Computer

Special Purpose computers are those computers which are used to solve a single and dedicated type of problem. eg. automatic aircraft landing, multimedia computers, etc.

Quantum Computers was first introduced by Richard Feynman. It uses quantum mechanical phenomena. It is the fastest computers imiating brain working.

Applications Of Computer

Now a days computers have been employed in almost all the aspects of professional and personal life. Some of the areas where computers are being used are as follows:

  1. Education – Computers have proved to be excellent teachers. educational institutes are using computers in may ways like tele-education, virtual classroom, online classes, etc.
  2. Science and Engineering – Scientists have been long users of it. A new adventure among scientists is the idea of a collaboratory, an Internet based collaborative laboratory, in which reasearches all over the world can work easily togethar even at a distance.
  3. Industry – Computers are used here to control manufacturing system and continous running of the machinery, Parameters like temperature, pressure, volume are monitored and controlled by computers, Robotics developed with the help of computers, plays a very crucial role here.
  4. Administration – Various departments of the government use computers for their planning, control and law enforcement activities.
  5. Health – Computers plays a very crucial role in this area. Activities like scanning, X-ray, tele-medicine, patient monitoring, patient records, diagnosis, etc. are performed with the help of computers.
  6. Multimedia – It isthe field concerned with the computers controlled integration of text, graphics, drawings, animation, audio and any other media where each type of information can be represented, stored, transmitted and processed digitally.
  7. Recreation – our entertainment and pleasure time have also been affected by computerisation.
  8. Banks – Computers can be used in the banks to keep the records of customer’s accounts.
  9. Military Personnel – They also make use of computers for their crucial tasks like determining the weather, computing the trajectories of missiles,etc.
  10. Business – Using a wide range of business software a company’s marketing division can produce sales forecasts and device new.
  11. Commerce – it is the activities of buying and selling of goods and services especially on a large scale.
  12. Publication – Computers have made publication process an easy one. Without computers, the different parts of a publication-text. illustrations and graphics-must be created individually, then cut out and pasted down to form a page layout.

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