Charles Babbage FRS (December 26 1791-October 18 1871 was an English mathematician, philosopher, mechanical engineer and (proto-) computer scientist who originated the idea of a programmable computer. Parts of his uncompleted mechanisms are on display in the London Science Museum.In 1991, working from Babbages plans, a difference engine was completed, and functioned perfectly. Built to tolerances achievable in the 19th century, the finished engine would have worked. Nine years later, the Science Museum completed the printer Babbage had designed for the difference engine;it featured astonishing complexity for the 19th century device.

Design of Computers

In recognition of the high error rate in the calculation of mathematical tables, Babbage wanted to find a method by which they could be calculated mechanically, removing human sources of error. Three different factors seem to have influenced him: a dislike of untidiness; his experience working on logarithmic tables; and existing work on calculating machines carried out by Wilhelm Schickard, Blaise Pascal, and Gottfried Leibniz. Babbage's engines were among the first mechanical computers. His engines were not actually completed, largely because of funding problems and personality issues. Babbage realized that a machine could do the work better and more reliably than a human being. Babbage directed the building of some steam-powered machines that more or less did their job, suggesting calculations could be mechanized to an extent. Although Babbage's machines were mechanical monsters, their basic architecture was astonishingly similar to a modern computer. The data and program memory were separated, operation was instruction based, the control unit could make conditional jumps and the machine had a separate I/O unit.