Analytical Engine and Difference Engine

One of the creative thinkers of the 19th century was the Englishman Charles Babbage (1792-1871) A.D. He is considered to be the Father of Modern Computer Science. Like Pascal and Leibniz, Babbage was a mathematician. And he too, wanted to build a machine that could perform difficult calculations accurately and quickly.

Babbage was Professor of Mathematics at Cambridge University and started a small model of his "Difference Engine". He demonstrated this machine to the Royal Society in the year 1823. The demonstration won government backing for Babbage who wished to produce a larger machine able to generate reliable astronomical and mathematical tables containing values accurate to 20 decimal places. The machine was never  completed because of mechanical difficulties. However, Babbage's researches led him to develop the concept of an Analytical Engine in the year 1833, essentially a general purpose automatic calculator, which he designed in 1834. This design owed much to Jacquard's invention and incorporated many features present in modern computers. He had a concept of using binary digits (Bits) in this machine.

His idea can be summarized in the following points:

1. Data and program instructions fed in via a device using a suitable medium (punched cards).
2. Storage facilities for data and instructions.
3. A mechanised unit for calculation - a "mill".
4. A suitable output device.

Note: Using his idea about 100 years later in 1937, Mark-I was developed by Howard Aiken.