Programming a Turing Machine
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Mike Bedford is fascinated by how simple computer architectures – such as a Turning Machine – can do anything the most powerful supercomputers can do.
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Alan Turning might not have built a physical realisation of his theoretical computer, but Mike Davey has. See www. aturingmachine.com. It works on a real tape, erasing old symbols and writing new ones as it goes. Behind the scenes it’s controlled by a Parallax Propeller microcontroller.
“How fast is a Turing Machine?” is surely a daft question since it’s a theoretical computer. For a mechanical implementation, though, Mike Davey (see page 92) came up with some estimates about his creation – from 3.1 operations per second to 6.2 seconds per operation.
Go to www. redfrontdoor.org/ turingmandelbrot.to see how the Mandelbot Set has been plotted on a TM. Amazing stuff!
Alan Turing is probably best known for his pioneering work on code breaking at the Government Code and Cypher School at Bletchley Park. In playing a key role in developing the electro-mechanical Bombe that was used to crack the Enigma cipher, Turing had a major impact on shortening World War II by an estimated two years and saving as many as 14 million lives.
Despite having been dubbed the “Father of Modern Computing”, however, his contributions to general-purpose computing are less well-appreciated. And here it’s interesting to note that his design for the ACE computer, a cut-down version of which was eventually built by the National Physics Laboratory in 1950, predated the Manchester Baby, the world’s first stored program computer, by three years. Arguably, though, his biggest contribution to computing was his vision for a machine that was never actually built, and would have been totally impractical had it ever become a
