Early men used sticks and stones to count cattle. In 450 B.C. china invented Abacus, **the first calculating device**. Abacus was used to add and subtract the numbers.

In 17th century, John Napier invented ‘Napier Bones’, Which was helpful in multiplication and division as well as addition and subtraction.

In 1642, a French mathematician Blais Pascal invented mechanical calculator. It had mechanical parts. This machine was named as ‘pascaline’ and it was used for addition and subtraction.

**Father of computer**

IN 1833, Sir charles Babbage designed first automatic computer, named ‘Analytcal Engine’. It was the base of today’s modern computer, so charles Babbage is Callled as ‘Father of computer.

In 1944, Howard Aiken invented first Electronic computer . It was named as Mark I.

ENIAC is short Form of Electronic Numerical Integarator and calculator. ENIAC is **the first electronic computter**. It was invented in 1946.

After arriving the first electonic computer ENIAC, a revolution come in computer world. The scientist made their best efforts to make the computer smarter, faster, each in use, versatile and more and powerful.

On the base of main electonic component used in computer, they are classified in 5 categories, called **Generations**. In each generation of computer the basic component is the same but there are difference in model and features that differs from computer to computer.