A Machine Designed to Eliminate Computation Errors
While checking the then-current navigational and engineering mathematical tables, Babbage found them full of errors introduced by manual computation and transcription, errors that in navigation and the like could directly cause disaster, and he thereby conceived building a mechanical device, the "Difference Engine," that could automatically complete polynomial computation and directly drive printing, seeking to eliminate wholly, at the level of physical mechanism, the errors manual computation and transcription might introduce.
A "Computer" Acknowledged Only a Hundred Years Later
The design blueprint of Babbage’s conceived "Analytical Engine" already contained an independent arithmetic unit, a repeatedly readable and writable memory unit, and a control unit executing operations by program instructions — almost the prototype of the von Neumann architecture of the modern computer a hundred years later; yet limited by the machining precision of the time this machine was never truly built in his life, and only in 1991 did engineers of the Science Museum in London, following his original design drawings, first successfully build a working physical model of the Difference Engine.