Z22 (computer)

The Z22 computer (or simply the or the Z22 ) was a 1955 by the physicist Lawrence Hanewinkel engineered and constructed for the Zuse KG computer. He was the first tube machine from West Germany after the GDR had developed with the D1 in 1950 such. The Z22 was one of the first mass-produced computer world. He is regarded as the most important computing machine for scientific institutions after the Second World War, as it allowed German colleges, universities and other scientific institutions for the first time an electronic data processing.


According to the models Z1, Z2, Z3, Z4, Z5 and Z11 the Z22 was the seventh computer model, which was developed under Konrad Zuse. Although the previous models from the Z4 have been supplied commercially, you can also include the Z22 to the first commercial computers; probably was an hired to Switzerland in 1950 Z4, the first ever commercially traded computer.

The development of the Z22 was about 1957 completed the first of a total of 55 copies were sold at the TU Berlin and Aachen in 1958. Among the first customers was also, for example, the Zeiss company, which henceforth had a computer for their optical calculations. Theodor Fromme, scientific director at Zuse and former employees at Zeiss, was instrumental in the circuit diagrams of the computer.

The Diebold - computer statistics show a total of 48 copies of the Z22 for July 1, 1971.


In the standard version the Z22 was equipped as follows:

  • Register set of 14 words core memory each 38 bit
  • Paper tape reader / puncher - as a mass storage
  • 380 V, 16 A three-phase supply
  • 600 electron tubes, connected as flip-flops.
  • Electric cooling system that requires a separate water connection

The clock frequency of the Z22 was 3 kHz, which corresponded exactly to the speed of the drum store. Data input could be done via the tape reader or via direct input of data to the drum storage unit as well as via push button for direct programming of the core memory.

The relatively rapid output of data could be made through a paper tape punch, a relatively fast reading on an opto - electric tape reader. Some data could be displayed on the built- in control panel glow lamps, the register contents constitute important.

As a combined input -output device Siemens teleprinter T100 were used with a built- in 5-channel paper tape reader and punch. This four " peripherals " in a machine were available: keyboard input, tape input, chart recorder output and punch tape output. Their work rate was ten characters / second and was significantly slower than the special mono devices keypunch and reader.


The Z22 was developed with the aim to be simpler than the programmable computer of the previous generation. It was programmed in machine code; each instruction was divided into 38 bits wide and five fixed-length fields:

  • The first 2 bits were always " 10 "
  • The next 5 bits contained a conditional operator symbol
  • The next 13 bits contain a symbol of operation
  • The next 5 bits contained a core - memory address
  • The last 13 bits contain a drum memory address

To simplify the programming on, was an assembler -like language called "Freiburger Code" developed. Key elements of this code were the Torschaltbits. Each of these bits turned on a goal by or to the issues raised in the address part of the instruction ( drum) memory cell, respectively, to the addressed register via a switching cascade. Each of the bits in the instruction part spoke to one goal - of which there were one each for the evaluation of a condition:

  • Value = 0,
  • Value <0,
  • Value> 0,
  • Value ≤ 0,
  • Value ≥ 0

The surgery doors led to a circuit

  • LLR for a shift by 1 step to the left - more precisely, there was only one gate for 2 steps to the left - in the PP program
  • R is a step to the right,
  • N for zero-setting,
  • A for add,
  • S for subtraction, etc.

The usual in later assembler load command had in Freiburg code encoding:

  • NA set to zero Add
  • RNA meant loading the halved value
  • LLNA demanded the loading of the doubled value.

This language was developed with the aim to simplify the implementation of mathematical algorithms; this goal has been achieved in practice.

Z22 today

The Karlsruhe University has a restored and fully functional copy with the serial number 13, which was built in 1958. This machine has been on permanent loan on 9 March 2005 the Centre for Art and Media Technology ( ZKM). It was taken apart by the two Zuse expert Hans Baumann and Helmut Kammerer and rebuilt at the ZKM. That Z22/13 is the oldest working, faithful tube computers in the world and is a listed building. Another fully functional Z22R stands on the campus of the University of Applied Sciences Suderburg (part of Ostfalia University of Applied Sciences).

The Konrad -Zuse- Computer Museum in Hoyerswerda ( Sachsen) has two - but no longer functioning - copies of the Z22. Another built for Prof. Hubert Cremer at RWTH Aachen copy was located in the former Computer Museum Aachen. Also, this is no longer functional.

In the head building of the University of Linz 10 is also located in front of the lecture halls HS9 & a no longer functioning copy. Another non -functioning Z22 is located in the Museum of Technology in Berlin.

In the Computer Museum of Applied Sciences Kiel is no longer a functioning device that can be viewed during normal opening times of the museum.

A Z22 is located in the computer science department of the Deutsches Museum in Munich.