Mechanical computer

From Wikipedia, the free encyclopedia
Hamman Manus R mechanical computer, produced in Germany by the DeTeWe company between 1953 and 1959

A mechanical computer is a computer built from mechanical components such as levers and gears rather than electronic components. The most common examples are adding machines and mechanical counters, which use the turning of gears to increment output displays. More complex examples could carry out multiplication and division—Friden used a moving head which paused at each column—and even differential analysis. One model, the Ascota 170 accounting machine sold in the 1960s, calculated square roots.

Mechanical computers can be either analog, using continuous or smooth mechanisms such as curved plates or slide rules for computations; or discrete, which use mechanisms like pinwheels and gears.[clarify]

Mechanical computers reached their zenith during World War II, when they formed the basis of complex bombsights including the Norden, as well as the similar devices for ship computations such as the US Torpedo Data Computer or British Admiralty Fire Control Table. Noteworthy are mechanical flight instruments for early spacecraft, which provided their computed output not in the form of digits, but through the displacements of indicator surfaces. From Yuri Gagarin's first spaceflight until 2002, every crewed Soviet and Russian spacecraft Vostok, Voskhod and Soyuz was equipped with a Globus instrument showing the apparent movement of the Earth under the spacecraft through the displacement of a miniature terrestrial globe, plus latitude and longitude indicators.

Mechanical computers continued to be used into the 1960s, but had steadily been losing ground to digital computers since their advent. By the mid-1960s dedicated electronic calculators with cathode-ray tube output emerged. The next step in the evolution occurred in the 1970s, with the introduction of inexpensive handheld electronic calculators. The use of mechanical computers declined in the 1970s and was rare by the 1980s.

In 2016, NASA announced that its Automaton Rover for Extreme Environments program would use a mechanical computer to operate in the harsh environmental conditions found on Venus.[1]


Curta Calculator

Punch card data processing[edit]

Starting at the end of the nineteenth century, well before the advent of electronic computers, data processing was performed using electromechanical machines collectively referred to as unit record equipment, electric accounting machines (EAM) or tabulating machines. By 1887 Herman Hollerith had worked out the basis for a mechanical system of recording, compiling and tabulating census facts.[14] "Unit record" data processing equipment uses punchcards to carry information on a one-item-per-card basis.[15][16] Unit record machines came to be as ubiquitous in industry and government in the first two-thirds of the twentieth century as computers became in the last third. They allowed large volume, sophisticated data-processing tasks to be accomplished before electronic computers were invented and while they were still in their infancy. This data processing was accomplished by processing punched cards through various unit record machines in a carefully choreographed progression. Data on the cards could be added, subtracted and compared with other data and, later, multiplied as well.[17] This progression, or flow, from machine to machine was often planned and documented with detailed flowcharts.[18] All but the earliest machines had high-speed mechanical feeders to process cards at rates from around 100 to 2,000 per minute, sensing punched holes with mechanical, electrical, or, later, optical sensors. The operation of many machines was directed by the use of a removable plugboard, control panel, or connection box.

Electro-mechanical computers[edit]

Harwell Dekatron

Early electrically powered computers constructed from switches and relay logic rather than vacuum tubes (thermionic valves) or transistors (from which later electronic computers were constructed) are classified as electro-mechanical computers. These varied greatly in design and capabilities, with some units capable of floating point arithmetic. Some relay-based computers remained in service after the development of vacuum-tube computers, where their slower speed was compensated for by good reliability. Some models were built as duplicate processors to detect errors, or could detect errors and retry the instruction. A few models were sold commercially with multiple units produced, but many designs were experimental one-off productions.

Name Country Year Remarks Reference
Automatic Relay Computer UK 1948 The Booths, experimental [19]
ARRA Netherlands 1952 experimental
BARK Sweden 1952 experimental
FACOM-100 Japan 1954 Fujitsu commercial [20]
FACOM-128 Japan 1956 commercial [21]
Harwell computer UK 1951 later known as WITCH
Harvard Mark I United States 1944 "IBM Automatic Sequence Controlled Calculator"
Harvard Mark II USA 1947 "Aiken Relay Calculator"
Imperial College Computing Engine (ICCE) UK 1951 Electro-mechanical[22] [23][24][25]
Office of Naval Research ONR Relay Computer USA 1949 6-bit, drum storage, but electro-mechanical relay ALU based on Atlas, formerly Navy cryptology computer ABEL [26][27][28][29]
OPREMA East Germany 1955 Commercial use at Zeiss Optical in Jena [30]
RVM-1 Soviet Union 1957 Alexander Kronrod [31]
SAPO Czechoslovakia 1957
Simon USA 1950 Hobbyist logic demonstrator magazine article
Z2 Germany 1940 Konrad Zuse
Z3 Germany 1941 Zuse
Z4 Germany 1945 Zuse
Z5 Germany 1953 Zuse
Z11 Germany 1955 Zuse, commercial
Bell Labs Model I USA 1940 George Stibitz, "Complex Number Calculator", 450 relays and crossbar switches, demonstrated remote access 1940, used until 1948 [32]
Bell Labs Model II USA 1943 "Relay Interpolator", used for wartime work, shut down 1962 [32]
Bell Labs Model III USA 1944 "Ballistic Computer", used until 1949 [32]
Bell Labs Model IV USA 1945 Navy "Mark 22 Error Detector", used until 1961 [32]
Bell Labs Model V USA 1946, 1947 Two units delivered, general-purpose, built in trigonometric functions, floating-point arithmetic [32]
Bell Labs Model VI USA 1949 General purpose, simplified Model V with several enhancements
Unnamed cryptanalysis multiplier UK 1937 Alan Turing [33][34]

See also[edit]


  1. ^ Hall, Loura (2016-04-01). "Automaton Rover for Extreme Environments (AREE)". NASA. Retrieved 2017-08-29.
  2. ^ Needham, Volume 4, Part 2, 445.
  3. ^ Needham, Volume 4, Part 2, 448.
  4. ^ Bodde, 140.
  5. ^ Fry, 10.
  6. ^ "Machines of the East". Ancient Discoveries. Season 3. Episode 10. History Channel. Archived from the original on 2021-12-21. Retrieved 2008-09-07.
  7. ^ Howard R. Turner (1997), Science in Medieval Islam: An Illustrated Introduction, p. 184, University of Texas Press, ISBN 0-292-78149-0
  8. ^ Donald Routledge Hill, "Mechanical Engineering in the Medieval Near East", Scientific American, May 1991, pp. 64–9 (cf. Donald Routledge Hill, Mechanical Engineering Archived 2007-12-25 at the Wayback Machine)
  9. ^ Abrams, Melanie (2018-02-16). "'The Beauty of Time'". The New York Times. ISSN 0362-4331. Retrieved 2022-06-04.
  10. ^ Kovács, Győző (2012), Tatnall, Arthur (ed.), "Hungarian Scientists in Information Technology", Reflections on the History of Computing, IFIP Advances in Information and Communication Technology, vol. 387, Berlin, Heidelberg: Springer Berlin Heidelberg, pp. 292–294, doi:10.1007/978-3-642-33899-1_18, ISBN 978-3-642-33898-4, retrieved 2022-06-23
  11. ^ Weibel, Peter (17 May 2005). Beyond Art: A Third Culture: A Comparative Study in Cultures, Art and Science in 20th Century Austria and Hungary. Springer. pp. 304–305. ISBN 9783211245620.
  12. ^ Hebime (2016-07-05). "Hungarian Gamma-Juhász predictor". WT Live.
  13. ^ "Z3 from FOLDOC". Retrieved 2020-07-02.
  14. ^ General Information Manual: An Introduction to IBM Punched Card Data Processing. IBM. p. 1.
  15. ^ Janda, Kenneth (1965). Data Processing. Northwestern University Press. p. 47.
  16. ^ McGill, Donald A.C. (1962). Punched Cards, Data Processing for Profit Improvement. McGraw-Hill. p. 29.
  17. ^ Machine Functions (PDF). International Business Machines Corp. 1957. 224-8208-3.
  18. ^ Flow Charting and Block Diagramming Techniques (PDF). International Business Machines Corp. 1959. /C20-8008-0.
  19. ^ Lavington, Simon Hugh (1980). Early British Computers: The Story of Vintage Computers and the People who Built Them. Manchester University Press. p. 62. ISBN 9780719008108.
  20. ^ "Fujitsu Facom 100". Retrieved 2017-07-26.
  21. ^ "FACOM 128A and 128B Relay Computers". Retrieved 2017-07-26.
  22. ^ "Profile for Tony Brooker at the University of Essex". Retrieved 2018-05-19.
  23. ^ "From the Arithmometer to Electronic Arithmetic – 1998". Imperial College Video Archive Blog. Cited video fragment. 2016-05-06. From 38:15 to 38:32. Retrieved 2018-05-14. {{cite news}}: External link in |others= (help)CS1 maint: others (link)
  24. ^ "Relay Digital Computer, Imperial College, Univ. of London". Digital Computer Newsletter. 3 (1): 4. April 1951.
  25. ^ Bowden, B. V. (ed.). "11. The Imperial College Computing Engine". Faster Than Thought. pp. 161–164 (103–105).
  26. ^ Boslaugh, David L. (2003). When Computers Went to Sea: The Digitization of the United States Navy. John Wiley & Sons. pp. 95–96. ISBN 9780471472209.
  27. ^ "The ONR Relay Computer". Digital Computer Newsletter. 4 (2): 2. April 1952.
  28. ^ A survey of automatic digital computers. Office of Naval Research, Dept. of the Navy. 1953. p. 75.
  29. ^ Wolf, J. Jay (1952). "The Office of Naval Research Relay Computer". Mathematics of Computation. 6 (40): 207–212. doi:10.1090/S0025-5718-1952-0050393-0. ISSN 0025-5718.
  30. ^ Augustine, Dolores L. (2007). Red Prometheus: Engineering and Dictatorship in East Germany, 1945–1990. MIT Press. p. 134. ISBN 9780262012362.
  31. ^ "Relay Computer RVM-1". Retrieved 2017-07-25.
  32. ^ a b c d e Belzer, Jack; Holzman, Albert G.; Kent, Allen (1976-03-01). Encyclopedia of Computer Science and Technology: Volume 3 – Ballistics Calculations to Box-Jenkins Approach to Time Series Analysis and Forecasting. CRC Press. pp. 197–200. ISBN 9780824722531.
  33. ^ Teuscher, Christof (2004). Alan Turing: Life and Legacy of a Great Thinker. Springer Science & Business Media. p. 46. ISBN 9783540200208.
  34. ^ Hodges, Andrew (2014-11-10). Alan Turing: The Enigma: The Book That Inspired the Film "The Imitation Game". Princeton University Press. pp. 175–177. ISBN 9781400865123.

External links[edit]