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 which provides lots of original information, photos and testimonies about the DEUCE computer.