
Wilhelm Schickard

Wilhelm Schickard (born 1592 in Herrenberg  died 1635 in Tübingen) built the first automatic calculator in 1623.
Contemporaries called this machine the Calculating Clock. It precedes the less versatile Pascaline of Blaise Pascal and the calculator of Gottfried Leibniz by twenty years. Schickard's letters to Johannes Kepler show how to use the machine for calculating astronomical tables. The machine could add and subtract sixdigit numbers, and indicated an overflow of this capacity by ringing a bell; to aid more complex calculations, a set of Napier's bones were mounted on it. The designs were lost until the twentieth century; a working replica was finally constructed in 1960.
Schickard's machine, however, was not programmable. The first design of a programmable computer came roughly 200 years later (Charles Babbage). And the first working programcontrolled machine was completed more than 300 years later (Konrad Zuse's Z3, 1941).
Resources
Curta Mechanical Calculator
Pascalina Mechanical Calculator
Charles Babbage
History of Computers
Source: http://en.wikipedia.org/wiki/Wilhelm_Schickard
