The Z1 was a motor-driven mechanical computer designed by German inventor Konrad Zuse from 1936 to 1937, which he built in his parents' home from 1936 to 1938.

[1][2] It was a binary, electrically driven, mechanical calculator, with limited programmability, reading instructions from punched celluloid film.

The “Z1” was the first freely programmable computer in the world that used Boolean logic and binary floating-point numbers; however, it was unreliable in operation.

The Z1 contained almost all the parts of a modern computer, i.e. control unit, memory, micro sequences, floating-point logic, and input-output devices.

The machine was only capable of executing instructions while reading from the punched tape reader, so the program itself was not loaded in its entirety into internal memory in advance.

"[8] "The [data] input device was a keyboard...The Z1's programs (Zuse called them Rechenpläne, computing plans) were stored on punch tapes using an 8-bit code"[8] Construction of the Z1 was privately financed.

'The memory was constructed from thin strips of slotted metal and small pins and proved faster, smaller, and more reliable, than relays.

The Z4 was the first attempt at a commercial computer, reverting to the faster and more economical mechanical slotted metal strip memory, with relay processing, of the Z2, but the war interrupted the Z4 development.

'[9] The Z1 was never very reliable in operation because of poor synchronization caused by internal and external stresses on the mechanical parts.