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The DEUCE was a product version of the Pilot ACE, produced by English Electric, which had assisted on the building of the Pilot ACE. It was aptly described by one user as "DEUCE has a fair claim to being, for programmers, the most complicated computer ever put into general production". No less than 33 were built; the last was sold in 1962. Roughly 20 were still running in 1965; the last operational DEUCE was shut down in 1967 (possibly 1971; sources differ).

The changes from the Pilot ACE were minor; mostly in the numbers of the various main memory delay lines. The DEUCE initially (in the Mark I and II) had 12 long ones (instead of 11), 4 single word lines, 3 doubles, and 2 quads (newly introduced with the DEUCE). It did contain more vacuum tubes than the Pilot ACE (in part because the DEUCE had a hardware divide unit) - 1,450, instead of around 1,000. The packaging was entirely different, and much more finished.

Input/output used a printer, as well as the punched cards of the Pilot ACE; magnetic tape drives and a paper tape reader and punch were also available. The Mark II DEUCE had IBM card equipment, which was superior. The DEUCE also had a drum, holding 256 tracks, each containing 32 words - the same size as the large delay lines. The Mark IA and Mark IIA had seven extra of the large delay lines.

Further reading

  • Alan Turing, B. E. Carpenter (editor), R. W. Doran (editor), A. M. Turing's ACE report of 1946 and other papers, MIT Press/Tomash, Cambridge/Los Angeles, 1986 - brief notes about the DEUCE are in the last document re-printed herein
  • David M. Yates, Turing's Legacy: A History of Computing at the National Physical Laboratory 1945-1995, Science Museum, London, 1997 - the DEUCE is covered on pp. 40-46
  • B. Jack Copeland (editor), Alan Turing's Automatic Computing Engine: The Master Codebreaker's Struggle to Build the Modern Computer, Oxford University, Oxford, 2005 - essays from a number of people, including one covering the DEUCE in some detail

External links