The Z11 was a computer, the first serially produced machine of the

Zuse KG Konrad Ernst Otto Zuse (; 22 June 1910 – 18 December 1995) was a German civil engineer, pioneering computer scientist, inventor and businessman. His greatest achievement was the world's first programmable computer; the functional program- ...

. Weighing , in 1955 it was built with

relays A relay Electromechanical relay schematic showing a control coil, four pairs of normally open and one pair of normally closed contacts An automotive-style miniature relay with the dust cover taken off A relay is an electrically operated swit ...

and stepwise relays. Beginning in 1957 the Z11 could be programmed by

punched tape Five- and eight-hole punched paper tape Paper tape reader on the Harwell computer with a small piece of five-hole tape connected in a circle – creating a physical program loop Punched tape or perforated paper tape is a form of data storage ...

s. It consumed 2 kW of electricity, and operated mechanically at a

frequency Frequency is the number of occurrences of a repeating event per unit of time. It is also occasionally referred to as ''temporal frequency'' for clarity, and is distinct from '' angular frequency''. Frequency is measured in hertz (Hz) which is ...

of 10 to 20 Hz. Both input and output were in decimal numbers, and it used

floating-point arithmetic In computing, floating-point arithmetic (FP) is arithmetic that represents real numbers approximately, using an integer with a fixed precision, called the significand, scaled by an integer exponent of a fixed base. For example, 12.345 can b ...

. The Z11 was first presented on the

Hannover Messe The Hannover Messe (HM; "Hanover Fair") is one of the world's largest trade fairs, dedicated to the topic of industry development. It is organized by Deutsche Messe AG and held on the Hanover Fairground in Hanover, Germany. Typically, there ...

in 1957. Today the

German Museum of Technology (German Museum of Technology) in Berlin, Germany is a museum of science and technology, and exhibits a large collection of historical technical artifacts. The museum's main emphasis originally was on rail transport, but today it also features e ...

and the Museum of Technology in Vienna exhibit one of the surviving Z11s.

External links

Z11 information
1950s computers Computer-related introductions in 1955 Konrad Zuse Computers designed in Germany {{computer-hardware-stub