Computer History By teejay Jun 3, 1936 Z1 Computer First freely programmable computer. May 23, 1942 ABC Computer Who was first in the computing biz is not always as easy as ABC. Sep 30, 1944 Harvard Mark I Computer The Harvard Mark 1 computer. Feb 5, 1946 ENIAC 1 Computer 20,000 vacuum tubes later... Aug 2, 1947 The Transistor No, a transistor is not a computer, but this invention greatly affected the history of computers. Jul 12, 1948 Manchester Baby Computer & The Williams Tube Baby and the Williams Tube turn on the memories. Mar 16, 1951 UNIVAC Computer First commercial computer & able to pick presidential winners. Nov 27, 1953 IBM 701 EDPM Computer IBM enters into 'The History of Computers'.