Z4 (computer)

The Z4 was an early digital computer designed and built by Konrad Zuse's company, Zuse Apparatebau, on an order placed by Henschel and Son in 1942. It was only partly assembled in Berlin and was finished at Goettingen in April 1945, too late for delivery before the collapse of Nazi Germany. Like the earlier Z2 it combined mechanical memory with electromechanical logic, and it was much like the Z3 but improved: it used 32-bit floating point words, had a unit that punched program tapes, and offered instructions such as square root, minimum, maximum and sine. In 1950 it was delivered to ETH Zurich, where it was the only working digital computer in Central Europe and inspired the ERMETH. It later served at the Franco-German research institute at Saint-Louis until 1959 and is now on display at the Deutsches Museum in Munich. It is arguably the world's first commercial digital computer and is the oldest surviving programmable computer.