What is Computer? | Computer kya hai?

The premier invention of this century is the Computer, most people are aware that a computer is an electronic device that can perform arithmetic (+ or - ... so on and logical (>< on) operation. Computer can perform certain tasks faster than human being.
So, you will get all the basis fundamentals of Computer. Whats is Computer? or Computer kya hai? and details about computer.

Let's start the main topic.

1.Definition of Computer
2.Elements of Computer
3.Function of Computer
4.How to work Computer
   A)Input Unit
   B)Output Unit
   C)Storage Unit (Primary Storage or Main Storage and Secondary Storage)
   D)Central Processing Unit (A.L.U & C.U)
  5.History of Computer
   A)First generation (1951-1958)
   B)Second generation (1959-1964)
   C)Third generation (1965-1971)
   D)Fourth generation (1971-PRESENT)
   F)Fifth generation
6.Types of Computer
   A)Digital Computer (Microcomputer, Minicomputer,Mainframe Computer & Super Computer)
   B)Analog Computers
   C)Hybrid Computer
7.Who Invented  Computer ?
8.Advantages of Computer
   B)Memory Capacity


What is computer or  Computer kya hai?

Computer definition is "A computer is an electronic device which store and process information or data to give meaningful result."

Elements of Computer

The five basic operations are performed by a computer system like Input, Output, Storage, Processing & Controlling.

o Input: The process by which data and instruction are entered into a computer system.

o Output: The process by which useful information generated inside a computer system is output.

o Storage: The process by which data and instruction are saved inside a computer system.

o Processing: The process by which logical and arithmetic operation processed according to the set of instruction.

  o Controlling: The process by which all the above operation are performed in proper sequence and timing.


Function of computer

Computer all the functions can be divided into the following four categories like;
  • Acceptation data: A computer can be programmed to accept data.
  • Processing: The accepted data can then be processed through a command or a series of commands forming a program to perform the mathematical and logical operations.
  • Storing data: The computer also offer the facility of storage by which your programs and data can both be stored for future reference and use.
  • Retrieving data: The stored data and programs can be retrieved from the memory whenever required.


How to work a Computer

 A block diagram of basic computer organization is as follows;

In Terms of Full Form:
Full form of A.L.U: Arithmetic Logic Units
Full form of C.U: Control Unit
Full form of C.P.U: Control Processing Unit

what is computer system & uses of computer

Input Unit

In order to perform any processing , data and instructions have to enter the computer, Input unit performs this task and links the computer with the external world. Input device can be of different types, like - Keyboard, Punch Card etc. The primary storage  (memory) of the computer is designed to accept data in binary codes. Input  devices required transforming data into binary codes. This transformation is accomplished by units called input interfaces. The functions performed by an input unit are; 

  • It takes instructions and data from the external world
  • It transforms the instructions and data into a form (binary code)acceptable to the computer.
  • It transfers the converted instruction and data to other elements of the computer systems for processing.


Output Unit

The output units supplies the results of computer processing to the outside world. The computers work with binary codes. So, the results are also in binary form. Before supplying the results to human users, the form has to be converted to one that is acceptable to human users. This conversation is done by units called output interfaces. The functions performed by output units are;

  • It takes the results produced by the computer in coded form.
  • It transforms these coded results into to form readable by the computer
  • It displays or prints the results for human users.


Storage Unit

Data and instructions received from input units are to be stored inside the computer system before actual processing is done. also, the results produced by the computer system are to be stored inside the computer for the further processing. So storage unit is required for instructions received from external world.
There are two types of storage units.

o Primary Storage or Main Storage:
The term of Primary Storage refers to the main memory of a computer, where both data and instructions are stored for immediate access and use by the computer's central processing units during processing. Primary storage is considered a volatile  form of storage, meaning that data and instructions are lost when the computer is turned off.

o Secondary Storage or Auxiliary Storage:

Secondary storage or Auxiliary storage is any storage device designed to retain data and instructions in a more permanent form. Secondary storage is nonvolatile, meaning that the data and instructions remain intact when the computer is turned off.

Central Processing Unit

The Central Processing Unit (C.P.U) comprises of the Control Unit and Arithmetic Logic Unit. If we compared to the human body, CPU is the brain of computer system. C.P.U activates and control the operations of others units of a computer system. The parts of the C.P.U are usually connected by an electronic component called a bus. The bus acts as an electronic highway between them.  To temporarily store data and instructions, the C.P.U  has storage devices called registers.

o Arithmetic Logic Unit:

During processing operations, all calculations and logical decisions (comparisons) are made in the Arithmetic Logic Unit (ALU), No processing takes place in the primary storage unit. The data and instructions stored in the primary storage unit , are transferred as and when required to the ALU where processing takes place. Intermediate results after processing are stored in primary storage unit and shifted to and from ALU  as many times as required. After the final processing , the results are stored in primary storage before release to external user. ALU perform the four arithmetic functions "add, subtract, multiply, divide and logic operations" or comparison such as less than (<), equal to (=), greater than (>)."

o Control Unit:

This unit does not do any processing, but directs and manage the entire computer system, It does not execute instructions itself, it tells other parts of the computer system what to do. It determines the movement of electronic signals between the main memory and the arithmetic /logic unit, as well as the control signals between the C.P.U and input/output devices.

History of Computer

Computer evolution or Computer history means the generation of computer. A computer system is combination of hardware and software so, the generation covers both hardware and software. The development of computer took places in five distinct phases know as Generation. These generations are categorized by their technology as follows;

First generation (1951-1958)

The first generation of computer was marked by the use of "vacuum tubes and wired circuitry" for the electronic components. This generation lasted until the end 1950s.

generation of computer 1st to 5th

Merits of First Generation of Computer:
  • Electronic digital computer
  • Quit Large in size
  • Heating issue 
  • Require special housing 

Demerits of First Generation of Computer:
  • Bulky size
  • Poor Reliability 
  • The computer were not portable

Computer Series first generation:
ENIAC: [Electronic Numerical Integrator and Calculator] is the first electronic computer develops in 1946.

EDVAC: [Electronic discrete Variable Automatic Computer]
EDSAC: [Electronic Delay Static Automatic Computer] was started in the early 1947

Second generation (1959-1964)

The second generation of computer marked by either Magnetic drum or magnetic core storage and later use of transistor in place of vacuum tubes. Second generation lasted until the first half 1960's

second generation of computer

Merits of Second Generation of Computer:
  • Smaller in size
  • Reliability is increased 
  • More Portable 
Demerits of Second Generation of Computer:
  • Maintenance requirement is still high 
  • Very Costly 
Computer Series second generation:
  • ICT (ICL) 1300
  • IBM 1401  


Third generation (1965-1971)

The third generation of computer replaced transistor with Integrated Circuits (ICs). This ICs are very small in size , also known as silicon chip. A single chip contained thousands of transistor.
third generation of computers

Merits of Third Generation of Computer:
  • Very Small in size
  • Much more Reliability
  • Easy Portable 
  • Power requirement become less
 Demerits of Third Generation of Computer:
  • Maintenance of IC requirement sophisticated technology
Computer Series third generation:
  • IBM-360 Series, ICL-1900, ICL-2903, PDP-11/45
New Terms:
  • Hardware / What is Hardware: Physical component of a computer.
  • Software / What is Software : Set of program is known as software.
  • Vacuum tubes: Electronic Device.
  • ICs: Integrated Circuits.

Fourth generation (1971-PRESENT)

The forth generation of computer replaced LSI chip with Integrated Circuits (ICs). A single chip contained thousand of transistor . Semiconductor memories replaced magnetic core memories.

4th generation of computer

 Merits of Fourth Generation of Computer:
  • Compact in size.
  • High Reliability.
  • Easily Portable.
  • Computation is much faster.
  • The cost and production is very less.
Demerits of Fourth Generation of Computer:Manufacture of LSI chips required sophisticated technology.

Fifth generation

The fifth generation computer is yet to arrive. these computer are based on VVLSI (Very Very Large Scale Integration) technology with sophisticated operating system interface capability. These computers will be based on advances in silicon technology. These computers are supposed to have thinking power, i.e they will have artificial intelligence.

fifth generation of computer


Types of Computer

There are three types of computer like; Digital Computer, Analog Computer & Hybrid Computer.

Digital Computer

A distinctive feature of a digital computer is that it computes by counting and adding operations. Digital computers are much faster than analog computer. The various classes of digital computer are;

A microcomputer is a small, low cost computer with a processor based on a single silicon chip . A microcomputer is also called a personal computer or PC.
This  machine is another advancement over the PC -AT . Here you can have a maximum of a few hundreds of dump terminals attached to the same CPU. Processing speed is also many times faster. One example is the IBM 9375. Microprocessor used in Intel 80286 or 80386.

Mainframe Computer: 
Mainframe computers  are faster and more sufficient than Minis and have a much larger storage capacity. Example are the IBM System /370 and IBM 4300 Series.

Super Computer:
Super Computers are most powerful and most efficient too, Super Computers are designed to process complex scientific applications. Super computer have the computing capacity of approximately 40,000,000 IBM PCs. Some examples are CARY-2,ETA-10, CARY X-MP.

Analog Computers

An Analog computer computes by measuring changes in a continuous physical phenomenon such as electric voltage, length, current, temperature, etc. The devices that measure such quantities are analog. The advantages of analog computer is that all the calculation take place in parallel and hence these are faster but their accuracy is poor.

Hybrid Computer

The hybrid computer uses both the analog and digital components.Hybrid computers use digital memory for the storage and analog devices for computational purpose.

Who invented the Computer?

Who made the computer or Who invented the computer there are lots of argument on computer filed. But Charles Babbage invented the computer there are no doubt on it, As   A.L.U - Arithmetic Logic Units, Basic flow control and integrated memory was implemented in first computer and these are all major contribution by British mathematician Charles Babbage between 1833 and 1871. 
So,  that is why Charles Babbage called Father of Computer also.
charles babbage father of computer

 Advantages of Computer

As you can see, computer are being used almost everywhere. The areas where computers are used Banking sector, Railway,Airway,Electricity departments, Billing, School, Colleges & Industries etc.  Some of the advantages that made these people to use computers are;


Computers are much faster as compared to human beings. A modern computer can execute millions of instructions in one second. The operations of personal computers are measured in thousands of a second or a millisecond.

Memory Capacity

Computers can store a large amount of information in a very small space. Computer can store billions of characters and perhaps thousands of image on disk that can be available for future use.


Computers can perform all calculations accurately provided the hardware does not malfunction.


Computers are immune to tiredness and boredom of fatigue.Thus computers are more reliable than human being.


Computers can perform repetitive jobs efficiently. Computers can solve labor problem or do hazardous jobs in a hostile environment. Computers even can work in the areas where the human brain can err, for instance,observing,the motion of very fast-moving articles. Also,computers can work with different types of data and information like graphics, audio-visual characters etc.

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