The computer is undoubtedly among mankind’s most important inventions. The ability to compute and store data provides us with the ability to tackle problems that would likely be impossible to handle otherwise. It’s hard to imagine scientists looking for the Higgs-Boson with nothing more than typewriters and legal pads.

The electronic data processing does not go back more than just half a centaury i.e. they are in existence merely from early 1940’s. In early days when our ancestor used to reside in cave the counting was a problem. Still it is stated becoming difficult. When they started using stone to count their animals or the possession they never knew that this day will lead to a computer of today. People today started following a set of procedure to perform calculation with these stones, which later led to creation of a digital counting device, which was the predecessor the first calculating device invented, was know as ABACUS.

**THE ABACUS**

Abacus is known to be the first mechanical calculating device. Which was used to be performed addition and subtraction easily. This device was a first develop Ed by the Egyptians in the 10th centaury B.C, but it was given it final shape in the 12th centaury A.D. by the Chinese educationists. Abacus is made of a wooden frame, metal rods, and wooden beads in which rod where fitted across with rounds beads sliding on the rod. It id dividing into two parts called ‘Heaven’ and ‘Earth’. Heaven was the upper part and Earth was the lower one. Thus any number can be represented by placing the beads at proper place.

**NAPIER’S BONES**

John Napier’s of Scotland invented a calculating device, in 1617 called the Napier Bones.It was a better calculating device. In this device, Napier’s used the bone rods of the counting purpose where some number is printed on these rods. Using this mechine they can do addition, multiplication, subtraction and division in efficent way.