---
title: ENGLISH ELECTRIC CO. DEUCE
categories:
- Computers
types:
- Professional Computer
origins:
- United Kingdom
years:
- '1955'
cpus:
- '1'
params:
  name: DEUCE
  image: /media/museum/photos/englishelec_deuce_system_s1.jpg
  company: /companies/english-electric-co
  company_name: ENGLISH ELECTRIC CO.
  specs:
  - label: NAME
    value: DEUCE
  - label: MANUFACTURER
    value: English Electric Co.
  - label: TYPE
    value: Professional Computer
  - label: ORIGIN
    value: United Kingdom
  - label: YEAR
    value: '1955'
  - label: END OF PRODUCTION
    value: '1964'
  - label: BUILT IN LANGUAGE
    value: None
  - label: KEYBOARD
    value: 32 Key Switches
  - label: CPU
    value: 1,450 Thermionic Valves
  - label: SPEED
    value: 1 Mhz clock - Serial Mode
  - label: CO-PROCESSOR
    value: None
  - label: RAM
    value: 1.6 KB Acoustic Mercury Memory
  - label: ROM
    value: None
  - label: TEXT MODES
    value: 2 X 6 inch monochrome CRT
  - label: SIZE / WEIGHT
    value: 14 ft (W) x 4 ft 6 in (D) x 6 ft 11 in (H) (92 sq. ft) / 2632 lbs - 1193.85 Kg
  - label: BUILT IN MEDIA
    value: 80 Column punch cards, 32 KB Magnetic Drum
  - label: OS
    value: None
  - label: POWER SUPPLY
    value: |-
      440 Volts 3 phase 50 Hertz AC - 9,000 Watts\
      +300V +200V +100V –100V –200V –300V DC - 6.3V AC @ 400 Amps
  - label: PERIPHERALS
    value: 12 extra delay line , paper tape I/O, magnetic tape
  - label: PRICE
    value: 50,000 UK Pounds
  tabs:
  - links
  links:
  - title: DEUCE's programmer experience
    url: http://www.ncf.ca/~ad161/deuce1.html
    text: ''
  - title: The languages of the DEUCE
    url: http://hopl.murdoch.edu.au/findlanguages.prx?id=2&which=byhw&Name=DEUCE
    text: ''
  comments:
  - author: audrey (louisiana)
    date: Saturday 7th December 2019
    text: im doing a social studies project and i picked the history of video games so,this was very helpful
  - author: Karma
    date: Friday 9th June 2017
    text: Apparently this was a smaller version of Alan Turing''s ACE because his colleagues thought that the ACE was too ambitious so they built the Pilot Model ACE which ended up becoming the DEUCE
  - author: william lindsay (uk)
    date: Wednesday 16th June 2010
    text: The DEUCE output drive had 32 6CH power pentodes in a box...just right for heating sausage rolls. A visiting "royal" ,searching for a comment and enjoyjng an aroma suggested we were cooking the results''
  - author: John Barrett (Sydney Australia)
    date: Wednesday 7th September 2005
    text: |-
      BRISTOL SIDDELEY ENGINES - PATCHWAY - Nr BRISTOL - Was later Rolls Royce. See

      http://www.users.tpg.com.au/eedeuce/people.html#S3
  - author: wilsonsamm (UK)
    date: Monday 21st February 2005
    text: Now, I don't know much about his computer, but I happen to know that the Rolls-Royce plant in Bristol had two such units, as well as two KDF-9s. They eventually sold the KDF-9s and replaced them with PDP-10 units from Digital.
  oc_id: 1089
  source:
    url: https://web.archive.org/web/20221129074155/http://www.old-computers.com/museum/computer.asp?c=1089
    date: '2022-11-29'
---

The DEUCE (Digital Electronic Universal Computing Engine) was an early British Computer manufactured by the English Electric Company in the 50s from designs used by the UK's National Physical Laboratory (N.P.L.) for the ACE Pilot Model (Automatic Computing Engine).

Physically, the DEUCE consisted of a cabinet, roughly 10' x 8' x 6', which housed all the circuitry needed and had the console at one end. Still no transistors or printed circuit boards, it contained hundreds of thermionic valves in lines of six foot tall racks of circuitry.

There were two kinds of storage. The high speed store consisted of mercury delay lines and held 402 words in all. There were 12 long delay lines holding 32 words each and some short lines, known as temporary stores, which held one, two and four words. The time taken for the contents of one delay line to circulate was called a 'major cycle', the time of one word was a 'minor cycle'. There were 32 minor cycles in one major cycle. The words were all of the same length, 32 binary digits (about 10 decimal digits).\
Words were stored in the delay lines as a succession of pulses of 1µ sec duration. A minor cycle was therefore 32 µsec and a major cycle was 1O24 µsec, or just over 1 m.sec. All operations were performed in the high speed store.

The secondary storage was a magnetic drum which holds 8192 words, disposed in 256 tracks of 32 words each. The drum itself was a rapidly rotating cylinder coated with magnetic material. There were 'reading heads' and 'writing heads', to transfer information to and from the high speed store. A whole track was transferred with one instruction. Access to the drum was much slower than to the high speed store.

Input and output were by means of conventional punched card equipment. Cards might be read at a rate of 200 per minute and punched at 100 cards per minute. 64 columns of a card were used by DEUCE, which means that 24 words punched in binary can be read from one card.

The console, at the front of the machine, had a bewildering array of keys and lights and two cathode ray monitor tubes. These tubes displayed the contents of the temporary stores and any selected long delay line.

Between 1953 and 1964, 33 machines were sold worldwide to various research and development establishments.

All this information is courtesy of the [DEUCE web site](http://users.tpg.com.au/eedeuce/intro.htm) which provides lots of original information, photos and testimonies about the DEUCE computer.