Seventy years ago today (April 2, 1943), John Mauchly and J. Presper Eckert of the Moore School at the University of Pennsylvania submitted a proposal for building an “electronic calculator” to the U.S. Army’s Ballistics Research Laboratory. The contract was signed on April 9 and the result was the ENIAC, the first electronic general-purpose computer, unveiled on February 14, 1946.

See also This Day In Information: ENIAC Dedicated; This Day In Information: Giant Brains; and When Mauchly Met Atanasoff: Creating the Digital Computer