Wilhelm Schickard (born 1592 in Herrenberg - died 1635 in Tübingen) built the first automatic calculator in 1623. This makes him the father of the computing era, and one of the most remarkable figures in computing history.

Contemporaries called his machine the Calculating Clock. It precedes the less versatile Pascaline of Blaise Pascal and the calculator of Gottfried Leibniz by several decades. Schickard's letters to Johannes Kepler show how to use the machine for calculating astronomical tables. The machine could add and subtract six-digit 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 program-controlled machine was completed more than 300 years later (Konrad Zuse's Z3, 1941).

External links

• Computer history speedup since 1623
• Wilhelm Schickard