d by 1822 he had built a small working model for demonstration. With financial help from the British government, Babbage started construction of a full-scale difference engine in 1823. It was intended to be steam-powered; fully automatic, even to the printing of the resulting tables; and commanded by a fixed instruction program.The difference engine, although of limited flexibility and applicability, was conceptually a great advance. Babbage continued work on it for 10 years, but in 1833 he lost interest because he had a "better idea" the construction of what today would be described as a general-purpose, fully program-controlled, automatic mechanical digital computer. Babbage called his machine an "analytical engine"; the characteristics aimed at by this design show true prescience, although this could not be fully appreciated until more than a century later. The plans for the analytical engine specified a parallel decimal computer operating on numbers (words) of 50 decimal digits and provided with a storage capacity (memory) of 1,000 such numbers. Built-in operations were to include everything that a modern general-purpose computer would need, even the all-important "conditional control transfer" capability, which would allow instructions to be executed in any order, not just in numerical sequence. The analytical engine was to use punched cards (similar to those used on a Jacquard loom), which were to be read into the machine from any of several reading stations. It was designed to operate automatically, by steam power, with only one attendant.Babbage's computers were never completed. Various reasons are advanced for his failure, most frequently the lack of precision machining techniques at the time. Another conjecture is that Babbage was working on the solution of a problem that few people in 1840 urgently needed to solve.After Babbage there was a temporary loss of interest in automatic digital computers. Between 1850 and 1900 great ...
