For the IBM mainframe computer formerly known as "z11", see zEnterprise 196.
The Z11 was a computer, the first serially produced machine of the Zuse KG.
Weighing 800 kg (1,800 lb), in 1955 it was built with relays and stepwise relays. Beginning in 1957 the Z11 could be programmed by punched tapes. It consumed 2 kW of electricity, and operated mechanically at a frequency of 10 to 20 Hz. Both input and output were in decimal numbers, and it used floating point arithmetic.