Konrad Zuse applied for a patent on his electromagnetic, program-controlled calculator, called the Z1.
Zuse built the machine in the living room of his parents’ apartment in Berlin. It had 30,000 parts.
The Z1 was the first freely programmable, binary-based calculating machine ever built, but it did not function reliably, and it was destroyed in World War II. Zuse's patent application is the only surviving documentation of Zuse's prewar work on computers.
Between 1986 and 1989 Zuse and three associates created a replica of the Z1, which is preserved in the Deutsche Technikmuseum, Berlin.
