First Computer?

Colossus faces rebirth into a world of dispute:There is controversy over whether a top-secret codebreakingdevice was really the world’s first computer. In Block H at Bletchley Park, three grey-haired electronics engineers were sorting through piles of old telephone switchboard parts. Beside them a loop ofteleprinter tape was being whizzed past photo-electric cells at the rate of5,000 characters a second, driven by the motor from an old domestic vacuumcleaner.At right-angles to the tape drive stood two parallel frames of grey metal festooned with objects that today’s micro-electronic boffins would havedifficulty recognising – transformers, resistors, capacitors and relays.The machine emitted clucks of sound, flickers of light, and a gentle heat thatpermeated the hut. Every half second, an old-fashioned typewriter, mountedchest-high on a stand beside it, would clatter out a line of numbers.This contraption is a re-creation of Colossus, the top-secret codebreakingdevice which helped unscramble the radio traffic of the German high commandduring the second world war. Thanks to its blinking valves and clicking switches, Winston Churchill was able to read Hitler’s orders to his generalsalmost day by day for the last 18 months of the war.The man behind the resurrection of Colossus is Tony Sale, a computer expert andformer MI5 operative who once worked for Peter Wright of “Spycatcher” fame. Itsreconstruction, now in its final weeks, is not merely an act of homage to themathematical supermen of Bletchley who hastened the Allied victory over theNazis. Neither is it just a triumph over the official secrecy in which the machine was cloaked until a few years ago. It is a working demonstration of Sale’s contention that Colossus was the world’s first computer.It is a controversial claim, especially for scientists in the US who earlierthis year celebrated the 50th anniversary of the “first computer in the world”.Who is right? In 1943, when the prototype Colossus was built at the Post Office’s researchlaboratory in Dollis Hill, north-west London, “computer” meant a person, not a thing. It would have been more readily applied to Bletchley’s 7,000 mathematicians, linguists, servicemen, clerks and secretaries than to machines devised for codebreaking.Yet the idea of automating calculation was an old one. An early proponent was the Englishman Charles Babbage (1791-1871)). But Babbage’s “analytical engine”was never realised in his lifetime due to a lack of engineering skills. In the 1890s, data processing arrived. Payroll, census and other statistics were fed on punched cards into machines which selected and sorted them and tabulated
results. By the 1940s the punch card “ran the world” and International BusinessMachines was in the driving seat, said Doron Swade, curator of computing at the Science Museum in London. Meanwhile the theory of a “universal” machine to manipulate symbols had been developed by Alan Turing, the awkward mathematical genius from Cambridge University, in a 1936 paper “On Computable Numbers”. Wartime brought Turing and a flock of fellow Cambridge mathematicians to Bletchley Park, a “Tudorbethan” mansion in 580 acres which had belonged to City stockbroker Sir Herbert Leon. Chosen as the government’s top secret communications base – now called Government Communications Headquarters (GCHQ) – it was a short walk from thejunction of the old Oxford-to-Cambridge and London railway lines. There, in Hut 8, Turing supervised the cracking of German naval signals which used the Enigma code. Enigma was a three-wheel (later four-wheel) encryption machine like a typewriter, a military specimen which had fallen into Polish hands. The story of Enigma, deciphered with the help of electro-mechanical”bombes” designed by Turing, is well known. But the code for which Colossus was invented to crack was another matter, and here Turing’s influence was only indirect.To understand Tony Sale’s claim for Colossus as the first computer, it is necessary to understand the job it was built to do. The code was generated by amachine called the Lorenz, a 12-wheel affair with a total of 501 metal lugs onthe wheels’ circumferences which could be turned “on” and “off” to create hugecombinations of patterns. The German operators would change the settings of thewheels for each message and the patterns on the wheels at least once a month. Because it was used for top-security messages, known to the Bletchley people as”Fish”, the Lorenz was, in theory, a great deal tougher to crack than the Enigma. Lorenz was as near to random as a machine could then get without being so cumbersome as to be militarily useless. There was no question of working systematically through the combinations. There were 10 1 9 possibilities, which,as Sale said, would give even a modern Cray computer a severe headache. But amachine is still a machine, and humans have an amazing ability to detect patterns in machine “randomness”.The Germans did not use Morse to send their encrypted messages but a pre-war teleprinter alphabet called Baudot in which each letter is represented by a combination of five on or off states. It is a binary system which can be transmitted as positive and negative impulses, written as dots and crosses or 0s and 1s, or transcribed as holes and spaces on a punch tape.Once the Lorenz machine had been set up it would add a “random” letter to eachletter of the message text. This addition used a logical convention where 0+1=1,1+0=1, 0+0=0 and 1+1=0 (repeat 1+1=0). The resulting garble would be transmittedby landline, undetected, or by radio, when it could be intercepted. By addingback the same string of nonsense letters on his own Lorenz machine, thereceiving operator revealed the message.The first intercept of “Fish” was made in 1941, of German army messages between Vienna and Athens. By July of that year the secret traffic was being laboriously deciphered by hand.

But on August 30 the cryptanalysts had a stroke of luck. A long message of 3,976characters, which Tony Sale calls “probably the most important message ever sentby the Germans”, was sent twice with the same wheel setting. By “adding” themtogether the codebreakers were able to infer the hidden message. By January the following year the mathematician Bill Tutte had cracked the whole structure -the logic – of the Lorenz machine and its 12 multi-tagged wheels.Professor Max Newman then decided to automate the process. The patterns on thewheels could only be worked out at this stage by brainpower. But the wheelsettings were revealed by comparing two, one containing an interceptedencyphered message, the other the patterns guessed by the codebreakers. The tapes were run on a 24-valve device called, with typical Bletchley humour, the”Heath Robinson”, after the cartoonist who specialised in drawings of fantastical gadgets. Once the wheel settings were broken, the message was run through another machine for decipherment. This was the “Tunny”. Though it looked nothing like the Lorenz – more like an old-fashioned telephone switchboard – it mirrored the logic of that encryption device.It was difficult to keep two punched tapes running synchronously at up to 30mph without stretching or breaking them. A Post Office engineer, Tommy Flowers, no win his 80s, had a brainwave. Why not do away with one of the tapes by generating the patterns using an electronic sequence inside the machine?The first Colossus, a monster for those days, boasted 1,500 valves. It was put together at Dollis Hill and carted up to Bletchley Park in December, 1943. By the following February it was working, in time to inform Churchill that his elaborate pre-invasion deception efforts were having some effect on Hitler.Colossus was doing in two hours what it took humans up to eight weeks to do. A 2,500-valve Mark II was ready in time for D-Day, when, thanks to Resistance sabotage and aerial bombardment of landlines which forced the Germans to send their messages by radio, about 300 high-level “Fish” orders were being intercepted and deciphered each month. So sophisticated was the machine intelligence at Bletchley Park that the very existence of Colossus was not revealed until 1970, according to Tony Sale. Afterthe war the government ordered 10 Colossi to be broken up – some say as part of an intelligence deal with the Americans. One may have survived at GCHQ’s newhome in Cheltenham until about 1960.
Gripped by a desire to assert the claims of Colossus, the former MI5 man asked GCHQ to reinstate his security clearance so he could work on the project. The parts could be found in any British telephone exchange up to the 1970s. Yet ittook until 1992 to get all the electronics declassified. Only last November was Sale allowed to demonstrate the machine’s ability to break the Lorenz wheel settings. Even today members of the public are forbidden to operate Colossus:some of its code
breaking algorithms are still, it seems, a secret. Was Colossus really a computer? It had no stored program and was set up before each run by means of plugs and switches on a board. It had virtually no memory.But Sale claims it was a very early example of parallel processing: separatelogic calculations were being carried out on each of the five longitudinal tracks of the tape.Sale describes the machine as a large electronic valve programmable logic calculator. “No lay person would argue that it is not a computer,” he says.Furthermore, because it wasted no time retrieving a stored program it was almost as fast as a high-speed modern computer whose nominal work-rate is 1,000 timesquicker. A simulation of Colossus which Sale ran on a top-of-the-range PentiumPC took twice as long as the real thing. In April 1944, while the first Colossus was rattling away at Bletchley Park, the Americans were designing at the engineering school of the University of Pennsylvania a machine to work out ballistic tables for artillery shells. This was Eniac, the Electronic Numerical Integrator and Calculator, containing no fewer than 19,000 valves, a number made necessary by the fact that Eniac did decimal arithmetic, not binary logic like Colossus. (Neither was a “universal machine” in the sense envisaged by Turing but both, as Donald Michie showed inEngland and John von Neumann in the US, could be adapted to perform a variety ofoperations.)Eniac was too late for the war and indeed was out of date before it was built.In February this year the US vice-president Al Gore, attending a ceremony tomark the 50th anniversary of Eniac’s first run, declared it to be “the first computer in the world”.Professor Maurice Wilkes, who oversaw the construction of an Eniac-type machine called Edsac (Electronic Delay Storage Automatic Computer) in Cambridge in 1948,says today that the Eniac was the first large-scale electronic computer. “And itwas a real computer in the sense that it was an arithmetical machine. It justwasn’t a stored-program computer.”That concept, embodied in Turing’s 1936 paper, was about to be made explicit ina report produced before VE Day by the Eniac team under the other “father of thecomputer”, the Hungarian-born John von Neumann. He named this machine Edvac(Electronic Discrete Variable Computer). “This was the first formal descriptionof a stored program computer,” says Doron Swade of the Science Museum. “It hadall the ingredients – input, output, processing and memory.” But Edvac never sawthe light of day under its own name.Meanwhile Turing was at the National Physical Laboratory struggling with redtape to get a machine built to his own design. As Alan Hodges described in his 1983 biography, The Enigma of Intelligence, Turing resigned from the project in1947, the year the transistor was invented. The complete ACE was unveiled in1957 as integrated circuits were appearing on the horizon.The first demonstration of a computer in the modern sense of the word occurredat the University of Manchester, England, on June 21, 1948. Most historian sagree that “Baby”, a demonstration machine built by a young postgraduate called Tom Kilburn under the late Prof F.C. Williams, was the genuine article – the first working stored-program electronic digital computer. A party is planned for Baby’s 50th anniversary, too.The rivalry is not unlike the search for the first man: a great deal depends on your definition. “I distrust any and all claims to be ‘first’,” says Dr MichaelWilliams, an historian of computing at the University of Calgary in Canada. “If you add enough adjectives to something it will always be first.”Computer archaeology is a strange business. The capacity of Colossus could now be stored on a single chip; today’s computer scientists would not recognise a thermionic valve if it winked at them. Yet the youngest can still shake hands with the oldest, men from the computer Stone Age like Tony Sale and his friend.