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Digital Electronic Universal Computing Engine

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The UK National Physical Laboratory developed the prototype, which it called an Automatic Computing Engine (ACE) in the 1950's. (The name DEUCE for the commercial version was obviously thought of before the words it claimed to represent). There is (or was) an ACE in the Science Museum in London. The idea was taken up and developed by English Electric Company Ltd., who sold quite a number to various research and development establishments. One such was the company's own guided weapons division in Luton, where I first used and later programmed and operated it.

This was first generation computing with a vengeance. Still no transistors or printed circuit boards, it contained thousands of thermionic valves in lines of six foot tall racks of circuitry. The machine filled a fairly large room, and the maintenance engineers (and others of us at times) could and did walk about inside it.

"High speed memory" (RAM to you) consisted of mercury acoustic delay lines, each holding 1, 2, 4 or 32 "words" of binary data, each word consisting of 32 bits. An instruction consisted of one such word, and they were never obeyed in the sequence in which they were stored, so each instruction had to nominate its successor! The entire memory consisted of just over 400 words (equivalent to 1600 bytes in today's terms) with a backing store of a surprisingly small (to look at) magnetic drum with a capacity of 8k words.

Input consisted of punched cards, together with a set of 32 on-off switches to set the thing going. Output was a card punch and two small, circular VDU screens which displayed every bit of the memory continuously, allowing a knowledgeable programmer to watch the progress of his calculations as they happened.

Of course such a machine had no operating system or BIOS, but had to be booted from scratch by the first card of each program as it was loaded - and all programming, of course, was in binary, with the cards punched manually, two 32 bit words to a line. The result of all this technology, of course, was very skilled programmers operating a machine with considerably less computing power than my present wrist watch!

There is an excellent site about DEUCE created by John Barrett. It includes photos of the machine and of typical programming input cards and coding sheets, and even a complete programmer's manual. It also has links to further sites about DEUCE and other early computers.

Another very good site about early computers is David Green's. His home page gives information about a number of early computers and includes descriptions of how some of the hardware, such as mercury acoustic delay lines, actually worked. He also has a page about DEUCE and, linked from it, a list of surviving documents about programming and using it.

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