What is Computer

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In today’s world, the computer is becoming a household gadget, which combines a TV, a telephone, an answering machine, a fax, a CD player and  internet connection all in one.

Every day, people use computers in new ways. Computer has become part of our day to day life.

We used computer in every fields like education, business, science, in the field of medicine, for domestic purpose, for entertainment etc, list is endless.

So it is very essential for every people to know – what is computer, how to use computer, what are the components of computer and how it works as computer science will be root of future opportunities, challenges and competition.   


The word “Computer” is derived from the word “Compute” in 1631. The word Compute means “Calculate”, “to count” “to sum up” or “work out” a figure or amount.

The word “Compute” origin from the Latin word “Computare“. Word computare is combination of two words Com + putare. Com means together and putare means to settle an account.

origin of computer


Computer is an electronic device or machine which capable to accept data from user, store digitized data, perform & process the operation in accordance with a set of instruction and give us the desired results as output.

Basic functions of computer:

A computer generally performs the following basic functions.

Step-1: Received data from user

Computer received instructions or data in the form of computer program (or high level language) through an input device like Keyboard, mouse, CD-ROM, Pen drive, scanner etc and placed it into memory. 

Step-2: Process, execute & store the data

Once the data received the CPU perform the operations with the help of other components, 1) Control Unit fetch the data, 2) decode the data, 3) Arithmetic logic unit execute the data and 4) Store the data to memory.  


Central Processing Unit

Step-3: Give output and result to worlds

Once the data is ready, computer sent back the data/ information through output device like monitor, printer, projector etc.

History of computers

In earlier, computer was a job title or given the name to those human beings whose job was to perform the repetitive calculations required to compute such things as navigational tables, tide charts, and planetary positions for  astronomical almanacs.

Scientists and inventors were searching for hundreds of years to find a mechanism that can perform calculations task quickly and accurately then human. Which basically begins the history of computer from gear driven calculating machine to today’s world i.e. Artificial Intelligence.

In 1822, English mathematician Charles Babbage’s designed Difference Engine to calculate the entries of a table automatically and transfer them via steel punches to an engineer’s plate from which the tables could be printed. Because of this invention, he is called father of computer.

Babbage’s Difference Engine was the first machine and an automatic mechanical calculator that could calculate and print mathematical tables.  But, difference engine was can only do one mathematical operation i.e. addition.

In 1834, by improving the concepts, Charles Babbage came up with a more powerful and ambitious machine i.e. Analytical Engine. This machine was designed to be a general purpose device that is capable of performing any mathematical operation automatically. This machine can do the four basic mathematical operation i.e. addition, subtraction, multiplication, division.

The history of computer is considered in terms of generation of computes. Computer generations refers to the specific improvements in computer technology with time. Each new generation, witnessed some changes in the size and functionality of the computer as a result computer became smaller and more advanced than the previous generation.

Generation of computers:

There  are five prominent generations of the computers which are discussed below.

First Generation of Computer (Vacuum Tubes):

  • The computers of first generation were made up of vacuum tubes and magnetic drums.
  • Vacuum tubes were used in computers during the year from 1940 through 1956.
  • Vacuum tubes were used for circuitry and magnetic drums used for memory.
  • Punched card were used to feed the information.
  • Magnetic tapes were used as external storage devices.
  • This generation of computer generated a lot of heat.
  • Vacuum tubes were larger components and as a result first generation of computers occupied a large amount of space in a room.
  • Example of first generation of computers are- UNIVAC, ENIAC, EDSAC, IBM-650, IBM-701 computers.

Second Generation of Computers(Transistors):

  • The computers of second generation were made up of transistors.
  • Transistors were used in computers during the period from 1956 through 1963.
  • Magnetic cores were used for primary memory and magnetic disc & tapes were used for secondary storage.
  • Transistors allowing computers to become smaller, faster, cheaper and more reliable than first generation.
  • Second generation computers still used punched cards for input and outputs.
  • Transistors were small in size so the machines occupied a less amount of space compare to vacuum tubes in first generation.
  • Some popular example of second generation of computers are- CDC 1604, CDC 3600, IBM 7030, IBM 70, IBM 094, Honeywell 400.

Third Generation of Computer (IC):

  • The computers of third generation were made up of IC (Integrated Circuits).
  • IC means incorporation of hundreds of transistors on a single silicon chip.
  • IC were used in computers during the period from 1965 through 1971.
  • User interacted with keyboards and monitors for input and outputs.
  • User interface with an operating system, which allowed the device to run different applications at one time.
  • IC allowing computers to become smaller, faster, cheaper and more reliable than transistors.
  • Less heat generated and occupied less space than transistors.
  • ICs still used in today’s computers.  
  • Some popular example of third generation of computers are- IBM-360/370/168, CDC 6600, Honeywell 6000 series, PDP, TDC-316.

Fourth Generation of Computer (Microprocessors):

  • Fourth generation computers were made up of Microprocessors, more commonly known as a CPU.
  • Computer used Very Large Scale Integrated (VLSI) and Ultra Large Scale Integrated (ULSI) circuits, ensured that millions of transistors and other components fit into a small chip.
  • Microprocessors were used in computers during the period from 1971 through 2010.
  • Reduced the size and price of the computers at the same time increasing power, efficiency and reliability.
  • Microprocessors along with integrated circuits, make it possible to fit easily on a desk.
  • First came the minicomputers, and offered word processors and spreadsheets.
  • In 1981, IBM introduced personal computers for office and home use.
  • Fourth generation went down from Desktop to Laptops to Palmtops. 
  • Macintosh introduced Graphic User Interface in which the users didn’t have to type instructions but could use Mouse for the purpose.
  • It allowed the networking of computers and World Wide Web Internets for the sharing of data. 
  • The programming languages i.e. C, C++, DBASE were also used in fourth generation.
  • Some popular example of fourth generation of computers are- Apple-II, DEC-10, START 1000, VAX-9000, IBM 5100, PDP-11, CRAY-1, CRAY-X-MP.

Fifth Generation of Computer (Microelectronic):

  • Fifth generation computers are the modern and advanced computers based on emerging microelectronic technologies with high computing speeds and parallel processing.
  • Integrated circuits with VLSI and Nano technology is beginning to use of Artificial Intelligence that has many potential applications around the world. 
  • The development of VLSI technology, become computers far more powerful, handy and more reliable than the previous generations.
  • Some popular example of fifth generation of computers are- IBM Watson, Pentium, PARAM, UltraBook, ChromBook.

Components of Computer:

A computer is a combination of multi parts of machine, which includes input devices, output devices and processing unit, which work together to produce results.

Major parts of computer is CPU, Monitor, Keyboard & Mouse .


Central Processing Unit, actually it is the brain/ heart of any computer. It is also known as processor or Microprocessor. The CPU is responsible for handling all instructions. CPU has three main components, 1) Arithmetic and Logic Unit(ALU) for manipulating data, 2) Registers for  storing data, and 3) Control Circuits for fetching and executing instructions.  

Monitor or Video Display Unit:

A monitor is the screen on which words, numbers and graphics can be seen. A computer monitor is an output device that displays information in pictorial form. Monitor connected to the CPU via VGA, DVI, HDMI or other connectors.


A keyboard helps us to enter data into the computer. In normal usage, the keyboard is used as a text entry interface for typing text and numbers into a word processor, text editor or any other program. A keyboard is also used to give commands to the computer.


Generally computer mouse are two types Corded mouse & cordless mouse. A computer mouse is a hand held pointing device that detects two dimensional motion relative to surface, which allows a smooth control of the graphical user interface of a computer. It has three buttons – left, right & scroll wheel buttons. 

Classification of Computer:

Computer are available in different shapes, sizes and weights, because of these different shapes and size, it perform different shorts of jobs. There are five types of computers:

  • Personal Computers
  • Mini Computers
  • Mainframe Computers
  • Super Computers
  • Laptop/ Palmtop Computers

Computer itself is a very big topic, which included number of areas and topics that is:

  • Discrete Mathematics
  • Computer System Architecture
  • Data Structure & Algorithms
  • Programming
  • Database Management System
  • Computer Graphics
  • Computer networking
  • Software Engineering
  • Operating system
  • Artificial Intelligence
  • Other topics

It is not possible to cover all nuts and bolts of computers in one article. All topics have different syllabus, topics, resources and books. So, I will try to cover all topics, one by one in detailed in different articles.

However, in this article, I have tried to give you a general over view about what is computer and hope you get a clear idea about this topic.

If you want to learn about Blogging, SEO, Digital Marketing, Ecommerce & Web Designing, you can read articles directly from following links:

Satyajit Nath

Satyajit is graduate in Information Technology and MS in Computer Science from the Manipal University, is also founder of SatyajitBlogs, Tazahindi and many other online ventures. He loves to writing about tech topics, like computer science, web designing, programming, computer architecture & blogging.

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    1. Satyajit

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