What Happened on November 12th

ILLIAC IV designer Dan Slotnick is born. The ILLIAC IV, a project of the Department of Defense’s Advanced Research Projects Agency and the University of Illinois, was the first large-scale array computer to use semiconductor RAM memory. When it first operated at NASA’s Ames Research Center in 1972, it could compute 200 million instructions per second. The speed of the parallel-processing computer was achieved by its architecture and the overlapping structure of its 64 processing elements.

Alan Turing’s paper entitled On Computable Numbers with an Application to the Entscheidungs-problem appeared on November 12, 1937, somewhat contemporaneously with Konrad Zuse’s work on the first of the Z machines in Germany, John Vincent Atanasoff ‘s work on the ABC, George Stibitz’s work on the Bell Telephony relay machine, and Howard Aiken’s on the Automatic Sequence Controlled Calculator.

Later renamed the Turing Machine, this abstract engine provided the fundamental concepts of computers that the other inventors would realize independently. So Turing provided the abstraction that would form the basic theory of computability for several decades, while others provided the pragmatic means of computation.