Computer History

The word computer comes from “compute” which means to calculate. But now days computers are also being used for many other purpose else calculating.

Thus the computer can be define as:

            It is an electronic device which accepts instructions in the form of input after processing it gives us information in the form of output.

Brief History of Computer

            The abacus, shows in below, is a calculator; its first recorded use was circa 500 B.C. The Chinese used it to add, subtract, multiply and divide.

1.      In 17^th century BLAISE PASCAL a mathematician and scientist of France developed the first mechanical calculator, which he called the “Pascalins”.

2.      CHARLES BABBAGE a mathematician of UK in 1822 designed a special type of calculator called “difference Engine” and in 1833 he developed a machine called “ANALYTICAL ENGINE”.

3.      Later on  American scientists Working at Howard University developed a computer between 1937 and 1943 called “HOWARD MARK-1”

4.      First electronic computer was developed in 1946 at the University of Pennsylvania USA.

5.      First personal computer (PC) was developed in 1981.

Characteristics of Computers

            Computers are powerful for a verity of reasons. They operate with amazing speed reliability consistency, and accuracy, computer can store huge amount of data and information.

Speed:

            Most computers carry out billions of operations in a single second. The words fastest computer can perform trillions of operations in one second. 

 Generations of Computer

Generation	Technology	Description
1st Generation (1942- 1955)	Vacuum Taube	Vacuum tubes (Fragile glass devices) were the only electronic component available during those days that possible to make electronic digital computer. These computers can calculate data in millisecond; these were very large in size. Example: UNIAC, EDVAC, EDSAC
2nd Generation (1956- 1964)	Transistor	The transistor (Solid State Device) a smaller and more reliable successor to the vacuum tube was invented in 1947. Faster in speed from the previous computers. These computers were able to reduce computational time form milliseconds to microseconds. Examples:  UNIVAC III, SS80, SS90, 1107
3rd Generation (1964 -1975)	Integrated Circuits	Advance Microelectronic technology made it possible to integrate larger number of circuit elements into very small (less then 5mm square) surface of silicon know as chip or Integrated Circuits (IC) Examples: IBM System/ 360 Series.
4th Generation (1975 – Present)	VLSI	Small Scale Integration (SSI) Contains ten to twenty ICs components. Medium Scale Integration (MSI) which has hundreds of integrated components in a single chip. Large scale integration (LSI) possible to integrated 30,000 components into a single chip. Very Large Scale integrations (VLSI) contains one million components integrated on a single chip. Example:  PC (Personal Computer)