HISTORY OF COMPUTER

arly Development Of Computer:Mechanical Calculating Device
1. Abacus
It is the first counting device, developed by Hindu philosopher, before 2500 years ago.It gives mathematical concepts and their issue, arthematical operations.It is only a memory-helping device rather than a real calculating machine.It is a rectangualr box,divided into two parts by mid bar, upper part is calles heaven, consist of two beads and each bead equal to value 5 and lower part is called earth,consist of five bead and each bead equal to value 1.While calculating beads are brought near to the mid bar.

2.Napier's Bones
Another interesting invention is Napier's bones, a cleaver multiplication tool invented in 1614 by mathematician John Napier(1550-1617), of Scotland. The
bones are a set of vertical rectangular rods, each one divided in 10 squares. The top square contains a digit and the remaining squares contains the first 9 multiples of the digit.Each multiple has its digital separated by a diagonal lines.When a number is constructed by arranging side by side the rod with the corresponding digits on the top, then its multiple can be easily obtained by reading the corresponding row of multiples from left to right while adding the digits found in the parallelograms formed by the diagonal lines. No wonderJohn Napier is also the inventor of the logarithms, a concepts used to change multiplication into addition.

3.Slide Rule
The slide rule is an analog device for performing mathematical computations.The first slide rules was created in 1620 by British mathematician William Oughtred(1574-1660). His device was based on the logarithmic scale created by British astronomer Edmud Gunter(1581-1626) in 1620. Gunter's work,in turn was based in the principle of logarithm set forth by Scottish mathematiclan John Napier(1550-1617) in1614.

4.Pascaline
Blaise Pascal(1623-1662), had a father who was an overworked and harassed tax commissioner.The young pascal devised a mechanical calculator to help him with his work. Pascal started on the project in 1642 when he was 19 and three years later he had a working machine, the Pascaline. In this machine numbers were entered by dialing a series of numbered wheels, and a series of toothed wheels transferred the movements to a result dial.Printed in wheel had the numbers from 0 to 9.It could add and subtract by the movement of wheels. The number of calculating capacity of pascaline was9,99,99,999.It is not used for division and multiplication.

5.Leibnitz Stepped Reckoner
Gottfried Willam Leibnitz(1646-1716) is perhaps best known for his work in thw calculus and his subsequent priority dispute with Newton,but he also condtructed a calculator, the Stepped Reckoner, which employed the stepped gear principle.This principle has been used in many more recent machines. The Stepped Reckiner was much more complex than Pascal's machine and could perform all four of the basic arithmetic functions.It also had a logical design fault in the carry mechanism, which was not discovered until many years later.The stepped gear or Leibnitz Eheel consists of a culinder having 9 gear teeth of varying lengths.

6.Charles Babbage
Charles Babbage(1792-1871)is an English man who is one of the creative thinkers in the field of comuputer science.He is considered to be the father of computer science.He is alsi the mathematician.He built am machine that could perform difficult calculation accurately and quickely.Now a days all computer are cased in his idea.He had the concept of usind binary digit in his machine.

7.Lady Augusta Ada Lovelace
She is the great person in the field of computer science. She is the first person to develop program by using binary system so she is cinsiderd top be the first programmer in computer science.