it.gen.nz

Writings on technology and society from Wellington, New Zealand

Thursday, November 15, 2007

The father of the computer

Today on Radio New Zealand National I talked about the man who is generally regarded as the father of the modern computer – someone who didn’t get recognition in his lifetime and died in ignominy. He’s now seen as one of the heroes of the twentieth century. Read on…

Q: OK, Colin – who did invent the computer?

A: Well, quite a number of people did some pioneering work – Ada Lovelace, for instance – she was Lord Byron’s daughter – his legitimate daughter that is, not the one he had by half-sister. Byron is the original subject of the quote ‘mad, bad and dangerous to know’, by Lady Caroline Lamb, a later lover. Not that Byron’s wife Annabella put up with him for long, she left and Ada left him when Ada was a month old. Ada was tutored in mathematics by her mother, who herself was very gifted and had been taught by a Cambridge professor.

Q: What did Ada Lovelace have to do about computers?

A: She wrote up Charles Babbage’s ideas for his machine called the analytical engine – she wrote a program for this machine even though it was never built. It’s her notes on the machine that are the reason anyone has heard of Babbage, and crucially, she and Babbage distinguished between hardware and software – that’s the bits of the a computer you can touch and the programs you run through it. The hardware was supposed to be brass rods and the like, and the program was to have been stored on punch cards. Punch cards were already in use by the Jacquard Loom, which had been invented in about 1800 – they described the actions that the loom would take to weave a pattern, so they were a form a program, even if not for a computer.

Q: OK, but Ada was early nineteenth century – real computers didn’t come along for a hundred years after that.

A: Quite so. Not much else happens in the history of computers until the 1930s with some really interesting thinking going on in Princeton, in the US. That was mainly driven by an Englishman called Alan Turing. He’s really the father of the computer.

Q: Ah, so we get to him. What did he do?

A: Well, he built some computers, eventually. But first of all in the thirties at Princeton he came up with a theoretical foundation for a computer, a kind of idealized machine that has since taken his name – a Turing machine.

You notice how hard it is to define a computer – how would you describe a computer?

Q: It has a screen and a keyboard…

A: Yes, but that’s all superficial. The important thing about a computer, the defining characteristic, is that it’s capable of executing tasks in a preset order and of varying that order based on the results of what it has already done. It an make decisions and act on them.

Q: But surely computers can’t do anything they haven’t been told to?

A: They can absolutely – but they are always working off a program. So you can tell a computer – only let a cat through the cat door if it’s wearing a special collar. Or, as one bright guy set a computer up, look at the cat through a camera and only let it in if it’s my cat, and only then if she’s not carrying anything in her mouth. This has saved a lot of semi-dead mice being introduced to this guy’s house! There’s a link to this one in today’s links.

And that was the point of Turing’s idealized machine. He imagined – and wrote extensively about – a machine which reads a tape, which has holes punched into it every centimeter, or sometimes no hole, just a blank with no hole. The machine reads the tape at a particular position, and as a result of what it reads – hole or no hole – and its internal state – it changes its internal state, punches a new hole or closes one up and moves one step left or right. Turing was a mathematician by vocation; and he used mathematical techniques to prove that the machine he described could in principle do anything that any kind of programmable machine could do. And he proved some very clever and useful theoretical results about his machine, which generalized to any computer. That, and actually building some, is why I see Alan Turing as the father computer.

Q: Tell me about what he did with stuff – was it all theoretical?

A: Absolutely not! Turing came back from his work at Princeton just before the Second World War, and he was immediately recruited by a rather shadowy arm of the British government – the Government Codes and Ciphers School – and moved to an architecturally monstrous country house in the English Midlands called Bletchley Park. And it was there that he broke the German odes during the war.

Q: This was Enigma, right?

A: Yes. Enigma was a very tough code to break – especially without computers. Although they used some work that had been done by a Polish mathematician, and gifted to the English just before the invasion of Poland in 1939, the men and women and Bletchley Park did something that no-one believed possible, especially the German High Command – they broke Enigma, and because the keys to Enigma were new every day, they broke it afresh every day. And, I have to say, that contribution was utterly key to Britain not losing the war. It meant that some of the convoys dodged the U-Boats, some attacks and battles were far more successful that they would other wise have been, because it gave the most senior members of the British High Command unparalleled knowledge of enemy movements, capabilities and expectations.

The British were desperate to avoid the Germans guessing that they had broken the code. So, the would send spotter planes up to specific areas where Enigma had already told them there was something of interest, just so that the Germans would report their presence which would stop them asking why the British knew where to attack.

Q: And how did this code-breaking involve computers?

A: it involved heavy doses of computers and mathematics – both Turing’s strengths. He built machines – today we’d call them computers, but then they were called ‘bombes’ – which searched for patterns in the Enigma coded messages. Those patterns could show the keys and the settings for the Enigma that day.

Q: So what did Turing do after the war?

A: He went on to build a number of other computers. Money was always a problem in austerity Britain, and the Americans soon pulled ahead in what they could build. But Turing’s personal life became a real issue in the 1950s.

Q: How so?

A: He was homosexual, and had never made a secret of that. His undergraduate degree was from Kings Cambridge, which was then and still is the most liberal of the old colleges. Even though homosexuality was very much frowned upon – and of course illegal – in Britain at the time, in academe and particularly in Kings and Trinity Cambridge, there was a great deal more acceptance of it than in the general population.

Turing’s problems came when in 1952 he reported a burglary to the police. He was living in Manchester at the time and working at the University there. The burglary was committed in part by a lover, and the police investigation centred on this rather than on Turing’s loss in the burglary. He was charged with gross indecency and was convicted. To avoid prison he agreed to a form of chemical castration, which involved him having oestrogen injections, which led to him growing breasts.

He eventually committed suicide, by lacing an apple with cyanide and biting into it. He always had been a big fan of Disney’s film of Snow White.

Q: Was he recognised for his achievements after his death?

A: Not immediately, but increasingly over the last couple of decades. There’s a statue to him in Manchester now, and numerous films and books have brought his contribution to public notice. The cruelest irony of all, of course, is that had the recruiters to the code school realized he was gay, he would never have been hired there and Britain might have lost the war as a result!

Q: It was that significant, what he did?

A: Yes. It made a huge difference. Churchill was one of the few in Britain who knew about is – another was the King – and Churchill used to sit up at night poring over the intercepts and figuring out his strategy.

Links

Wikipedia on Ada Lovelace and Charles Babbage.

The computerised cat door – very cool.

A recent book about Alan Turing, and one about wartime codebreaking.

A novel by Neal Stephenson about codes, with a fictitious appearance by Alan Turing.

posted by colin at 11:57 am  

1 Comment

  1. Really good and really interesting post. I expect (and other readers maybe :)) new useful posts from you!
    Good luck and successes in blogging!

    Comment by HeavyGod — 27 November 2007 @ 9:08 pm

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