A million punched cards

I went off today to see the movie The Imitation Game, the story of how Alan Turing cracked Germany's Enigma Machine during WWII. A lot of reviewers thought it was a great story but only a conventional biographical movie. Whatever. I enjoyed it and recommend it. One does not need to be a computer geek to follow what is going on. The movie delves into security issues and has some spy-counterspy elements. It also gets into how to make sure the Germans don't know their code has been cracked and the consequences that has.

Benedict Cumberbatch does an excellent job as Turing and shows him as a very logical man clueless in social graces. There are flashbacks to Turing as a 15 year old at boarding school. His friend gives him a book on cryptography and he wonders how is that any different from the way people normally talk – they say things that don't make any sense and one is expected to understand. The movie does discuss Turing's homosexuality when appropriate, such as when he proposes marriage to his female colleague to avoid her submitting to the pressure of her parents to return home to marry. And, of course, after the war when Turing is convicted of gross indecency for being gay.

Knowing this movie was coming I finally got around to reading Turing's Cathedral by George Dyson. It is a history of the development of the computer. Though Turing is discussed in the book the major character is John von Neumann. He is essentially the leader of the team that took Turing's idea of a computational machine and built one at Princeton University during WWII and a second one in the early 1950s. He developed the central architecture of the modern computer, which is why they're sometimes called von Neumann machines.

The book is dense with people and ideas – there is a six-page list of characters (each with a tiny bio) at the front of the book. Dyson is quite thorough with both. He explains the atomic bomb and the computer needed each other and neither would have been developed without the other. The computer was needed to calculate the bomb blast so the bomb could be configured to maximum effect. This early computer had about 5K of memory (about what it takes to display an icon on a modern computer). The algorithm performed a long series of calculations, but couldn't store intermediate values in the computer's memory, so after each computation cycle the numbers were dumped to punched cards and read in again. One massive calculation took a million cards. I remember those cards – I used them in college. A box of them held 2000 cards. This calculation would have needed 500 boxes. After the war the second computer was used to design the hydrogen bomb.

But the team couldn't say they were working on a bomb. They needed a cover story, another problem that couldn't be solved by a room full of women with mechanical calculators. And they had one – weather forecasting. All thy early problems spread across the time scale: nuclear explosions that happen in microseconds, blast waves that happen in microseconds to minutes, weather that deals with minutes to years, biological evolution that deals in years to millions of years, and stellar evolution that deals in millions to billions of years. The description of biological evolution was the hardest for me to follow. I would have liked a much more complete explanation of what exactly was being modeled and how – this was being done about the time the molecular structure of DNA was figured out.

Hannes Alfvén of Sweden received a Nobel prize in physics in 1970 for work he began in 1942. In 1966 he published a fable he had written for his grandson titled The Tale of the Big Computer. Dyson explores this book because he says it predicted such things as a global computer networks with features of Google and Facebook and cell phones with online purchasing. Alfvén also describes a world in which humans had to be excluded from the most important organizational tasks because computers could do them so much better.

As for that title, Dyson says he found Turing's Cathedral when he visited the headquarters of Google.

I was invited to Google's headquarters in California, and given a glimpse inside the organization that has been executing precisely the strategy that Turing had in mind: gathering all available answers, inviting all possible questions, and mapping the results. I felt I was entering a fourteenth-century cathedral while it was being built. Everyone was busy placing one stone here and another stone there, with some invisible architect making everything fit. Turing's 1950 comment about computers being "mansions for the souls that He creates" came to mind.