Punched Card

In 1880s, Herman Hollerith designs a system to record census data . The information is stored as holes in cards, which are interpreted by machines with electrical sensors. Hollerith starts a company named Tabulating Machine company that will eventually become IBM(International Business Machine), which is by far the most popular personal computer manufacturer . Hollerith proposed a mechanized method to count the cencus, which was based on punched cards. The cards were punched by a machine called Punched Card Machine.

Lady Augusts Ada Lovelace

One of the great supporters of Charles Babbage was Lady Augusta Ada (the daughter of famous poet, Lord Byron) . She convinced babbage to use binary concept in his Analytical Engine . She had some programs to use in Analytical Engine and so , She is considered as the First Programmer in history and has to her credit a computer language called ADA named after her.

Analytical Engine (Difference Engine)

In 1823 A.D. an English Mathematician (Professor of Mathematics at cambridge University) invented a machine called Difference Engine with machanical memory to store results. After sometime he design a bigger machine, which could comput up to 20 decimal places called Analytical Engine in 1830s. This machine was made to solve differential equations. Since Charles Babbage contributed to develop actual calculating device, he is considered as the Father of Computer. Using the principles of Charles Babbage , about 100 years later.

Leibniz's Calculating Machine

In 1671 A.D. a German Philosopher Gottfried Von Leibniz creates a more reliable adding machine that adds, subtracts, multiplies, divides and calculates square roots. It was the first calculator that could perform the above mentioned arithmetical calculations automatically.

Pascaline

In 1642 A.D., a french mathematician Blaise Pascal began to design the first mechanical calculating machine. This machine had a capacity of adding or subtracting 8 column numbers. This machine could add and subtract only, it could not carry out multiplication and division.

Slide Rule

After the invention of Logarithms in 1614 A.D. William Outhtred invented the Slide Rule . This device was made on the principle of Logarithms. It consists of two graduate scales, on of the passes over the other. The scales are devised in such a way that suitable alignment of one scale against the other makes it possible to obtain products, quotients or their function by inspection. The Slide Rule was used by the engineers till 1970s. This was replace by pocket calculator.

Napier's Bones

In 1614 A.D., a scottish mathematician John Napier developed the concept of Logarithms. It was very helpful in multiplication of long numbers. In 1617 A.D. Napier constructed a set of rods called Napier Bones for doing mathematical calculation easily. There were 11 rods . By using this device, people can get the result only with the help of a pencil and paper.