The history of input dataprocessing gearbased computing starts in 1623,
when Wilhelm Schickard built mankind's
first automatic calculator.
Schickard's machine could perform basic
arithmetic operations on integer inputs.
His letters to Kepler,
discoverer of the laws of planetary motion,
explain the application of his "calculating clock"
to the computation of astronomical tables.
The nonprogrammable Schickard machine was based on the
traditional decimal system.
Leibniz subsequently discovered
the more convenient principles of binary computers (1679), an essential
ingredient of the world's first working programcontrolled
computer, due to Zuse (1941).
