Z2 (computer)

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Drawing of the Zuse Z2
DeveloperKonrad Zuse
TypeElectromechanical (mechanical and relay-based) digital computer
Release date1940; 83 years ago (1940)
CPU600 electrical relay circuits @ ca. 5 Hz
Memory64 words
Removable storagePunch cards
Power1000 watts
Mass300 kg (660 lb)

The Z2 was an electromechanical (mechanical and relay-based) digital computer that was completed by Konrad Zuse in 1940.[1][2][3] It was an improvement on the Z1 Zuse built in his parents' home, which used the same mechanical memory. In the Z2, he replaced the arithmetic and control logic with 600 electrical relay circuits, weighing over 600 pounds.

The Z2 could read 64 words from punch cards. Photographs and plans for the Z2 were destroyed by the Allied bombing during World War II.[4] In contrast to the Z1, the Z2 used 16-bit fixed-point arithmetic instead of 22-bit floating point.

Zuse presented the Z2 in 1940 to members of the DVL[1][2][3] (today DLR) and member Alfred Teichmann [de], whose support helped fund the successor model Z3.[5]


Frequency Ca. 5 Hertz
Arithmetic Unit Fixed point arithmetic unit with 16 bit word length
Average calculation Speed 0.8 sec for addition operation
Number of Relays 600
Memory 64 words (same as Z1)
Power Consumption 1000 watts
Weight 300 kg (660 lb)


See also[edit]


  1. ^ a b Weiss, Eric A. (Summer 1996). "Konrad Zuse Obituary". IEEE Annals of the History of Computing. 18 (2): 3–4. doi:10.1109/mahc.1996.489747. ISSN 1058-6180.(NB. Z1 and Z2.)
  2. ^ a b Williams, Michael Roy (1985). A history of computing technology. Prentice-Hall. p. 219. ISBN 978-0-13389917-7. Retrieved 2022-07-10. (NB. Also search the book for Luftfahrt - further part.)
  3. ^ a b De Mol, Liesbeth (2007). "Chapter 4.1.3 Zuse's Z1, Z2, Z3, Z4 and Plankalkül". Tracing Unsolvability. A Mathematical, Historical and Philosophical Analysis with a Special Focus on Tag Systems (PDF). p. 212. Archived (PDF) from the original on 2022-03-16. Retrieved 2018-05-12. [1] (xii+679 pages)
  4. ^ Zuse, Horst (2000). "Konrad Zuse's Z1 and Z3 Computers". The Life and Work of Konrad Zuse. EPE Online. Archived from the original on 2008-06-01. Retrieved 2008-06-17.
  5. ^ Hellige, Hans Dieter, ed. (2004). Geschichten der Informatik. Visionen, Paradigmen, Leitmotive (in German). Berlin, Germany: Springer-Verlag. p. 115. ISBN 3-540-00217-0.
  6. ^ Zuse, Horst (2015). "Z2 Data Sheet". Archived from the original on 2022-02-22. Retrieved 2015-02-09.

Further reading[edit]

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