Model V

The Model V was among the early^[2] electromechanical^[3] general purpose computers,^[4][5][6] designed by George Stibitz and built by Bell Telephone Laboratories, operational in 1946.

Relay equipment room of the Model V Computer installed at BRL^[1]

Only two machines were built: first one was installed at National Advisory Committee for Aeronautics (NACA, later NASA), the second (1947) at the US Army’s Ballistic Research Laboratory (BRL).^[7][8]

Construction

Design was started in 1944.^[9] The tape-controlled (Harvard architecture)^[4][10] machine had two (design allowed for a total of six) processors ("computers")^[11] that could operate independently,^[5][12][13] an early form of multiprocessing.^[4][14]

The Model V weighed about 10 short tons (9.1 t).^[9][15]

Significance

• Inspired Richard Hamming to investigate the automatic error-correction, which led to invention of Hamming codes^[16][17]
• One of the early^[2] electromechanical^[3] general purpose computers^[4][5][6]
• First American machine^[18] and first George Stibitz design^[19][20] to use floating-point arithmetic^[21]
• Had an early form of multiprocessing^[4][14]
• Had a very primitive form of an operating system, albeit in hardware. A separate hardware control unit existed to direct the sequence of computer operations.^[22]

Model VI

Built and used internally by Bell Telephone Laboratories, operational in 1949.

Simplified version of the Model V (only one processor,^[23] about half the relays) but with several improvements,^[5][24][25] including one of the earliest use of the microcode.^[26][27][28]

Bibliography

• Research, United States Office of Naval (1953). A survey of automatic digital computers. Models V and VI. Office of Naval Research, Dept. of the Navy. pp. 9–10 (in reader: 15–16).
• "The relay computers at Bell Labs : those were the machines, part 2". Datamation. The relay computers at Bell Labs : those were the machines, parts 1 and 2 | 102724647 | Computer History Museum. part 2: pp. 47, 49. May 1967.
• Irvine, M. M. (July 2001). "Early digital computers at Bell Telephone Laboratories". IEEE Annals of the History of Computing. 23 (3): 25–27. doi:10.1109/85.948904. ISSN 1058-6180. pdf
• Kaisler, Stephen H. (2016). "Chapter Three: Stibitz's Relay Computers". Birthing the Computer: From Relays to Vacuum Tubes. Cambridge Scholars Publishing. pp. 35–37. ISBN 9781443896313.
• "Г. – Bell Labs – Model V" [G. – Bell Labs – Model V]. oplib.ru (in Russian). Archived from the original on September 29, 2022. Retrieved 2017-10-11.

Further reading

• Alt, Franz L. (1948). "A Bell Telephone Laboratories' computing machine. I". Mathematics of Computation. 3 (21): 1–13. doi:10.1090/S0025-5718-1948-0023118-1. ISSN 0025-5718.
  • Alt, Franz L. (1948). "A Bell Telephone Laboratories' computing machine. II". Mathematics of Computation. 3 (22): 69–84. doi:10.1090/S0025-5718-1948-0025271-2. ISSN 0025-5718.
  • Tomash, Erwin (2008). "The Erwin Tomash Library on the History of Computing: An Annotated and Illustrated Catalog". www.cbi.umn.edu. CBI Hosted Publications. Image: Bell Labs Model V.drawing of Model V, description: A Chapter, pp. 36-37. Retrieved 2018-05-08.
• Andrews, Ernest G. (1949-09-01). "The Bell Computer, Model VI". Proceedings of a Second Symposium on Large-scale Digital Calculating Machinery: 20–31 (58–69).
• "Bell Laboratories Digital Computers". Bell Laboratories Record. www.americanradiohistory.com. XXXV (3): 81–84. Mar 1957.
• Ceruzzi, Paul E. (1983). "4. Number, Please - Computers at Bell Labs". Reckoners: The Prehistory of the Digital Computer, from Relays to the Stored Program Concept, 1935-1945. Greenwood Publishing Group, Incorporated. pp. 95–99. ISBN 9780313233821.
• Bullynck, Maarten (2015). "3. Bell Model V Calculator: Tapes and Controls". Programming men and machines. Changing organisation in the artillery computations at Aberdeen Proving Ground (1916-1946). pp. 9–12.