Konrad Zuse, a German engineer (b. 1910) died on this day in 1995. He designed the Z3 computer.
The Z3 was the world’s first working programmable, fully automatic digital computer. It was built with 2,600 relays, implementing a 22-bit word length that operated at a clock frequency of about 4–5 Hz. Program code was stored on punched film. The initial values were entered manually.
The Z3 was completed in Berlin in 1941 but was not considered vital, so it was never put into everyday operation. Based on the work of Hans Georg Küssner’s “Program to Compute a Complex Matrix” it was written and used to solve wing flutter problems.
Zuse asked the German government for funding to replace the relays with fully electronic switches, but funding was denied during World War II since such development was deemed “not war-important”.
The original Z3 was destroyed on 21 December 1943 during an Allied bombardment of Berlin. The Z3 was originally called V3 (Versuchsmodell 3 or Experimental Model 3) but was renamed to not be confused with Germany’s V-weapons.
A fully functioning replica was built in 1961 by Zuse’s company, Zuse KG.
On this day in 1947 a moth lodges in a relay of a Harvard Mark II computer at Harvard University, causing the first case of a computer bug.
The Harvard Mark II, also known as Aiken Relay Calculator, was a computer built under the direction of Howard Aiken and was finished in 1947. It was financed by the United States Navy. Howard Aiken and Grace Hopper worked together to program and build the Mark II.
The IBM Personal Computer, commonly known as the IBM PC was introduced on August 12, 1981. It was created by a team of engineers and designers under the direction of Don Estridge of the IBM Entry Systems Division in Boca Raton, Florida.