PDF - Alan Turing. This is the official book that inspired the film The Imitation Game, which stars Benedict Cumberbatch and Keira Knightley, and which has. Copyright, Princeton University Press. No part of this book may be distributed, posted, or reproduced in any form by digital or mechanical means without prior. Alan Turing: The Enigma. Till good Sir Robert pleads his claim. To give once more the line to fame: Banff 's castled towers ring loud and high. To kindly.
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It is only a slight exaggeration to say that the British mathematician Alan Turing ( ) saved the Allies from the Nazis, invented the computer and artificial. eBook (PDF): Updated edition with a New preface by the author: Publication Date : Andrew Hodges' book Alan Turing: The Enigma, is the indispensable. Alan Turing: The Enigma, biography of Alan Turing () by Andrew Hodges.
He is also wonderful at the emotional nuance of Alan's life, who was a somewhat odd--a student was assigned to him in school to help him maintain a semblance of tidiness in his appearance, rooms and school work and at Bletchley Park he was known for chaining his tea mug to a pipe--but he was also charming and intelligent and Hodges brings all the aspects of his personality and life into sharp focus.
This account of Turing's life is a definitive scholarly work, rich in primary source documentation and small-grained historical detail. It is hard to imagine a more thoughtful and compassionate portrait of a human being.
Hodges examined available primary sources and interviewed surviving witnesses to elucidate Turing's multiple dimensions. A mathematician, Hodges ably explained Turing's intellectual accomplishments with insight, and situated them within their wider historical contexts.
He also empathetically explored the centrality of Turing's sexual identity to his thought and life in a persuasive rather than reductive way.
Perceptive and absorbing, Andrew Hodges's book is scientific biography at its best.
Scott, New York Times "One of the finest scientific biographies I've ever read: authoritative, superbly researched, deeply sympathetic, and beautifully told. Computational universality A system is called universal with respect to a class of systems if it can compute every function computable by systems in that class or can simulate each of those systems. Typically, the term universality is tacitly used with respect to a Turing-complete class of systems.
The term "weakly universal" is sometimes used to distinguish a system e. History[ edit ] Turing completeness is significant in that every real-world design for a computing device can be simulated by a universal Turing machine. This says nothing about the effort needed to write the program , or the time it may take for the machine to perform the calculation, or any abilities the machine may possess that have nothing to do with computation. Charles Babbage 's analytical engine s would have been the first Turing-complete machine if it had been built at the time it was designed.
Babbage appreciated that the machine was capable of great feats of calculation, including primitive logical reasoning, but he did not appreciate that no other machine could do better. From the s until the s, mechanical calculating machines such as adders and multipliers were built and improved, but they could not perform a conditional branch and therefore were not Turing complete.
In the late 19th century, Leopold Kronecker formulated notions of computability, defining primitive recursive functions. These functions can be calculated by rote computation, but they are not enough to make a universal computer, because the instructions which compute them do not allow for an infinite loop.
In the early 20th century, David Hilbert led a program to axiomatize all of mathematics with precise axioms and precise logical rules of deduction which could be performed by a machine.
Soon, it became clear that a small set of deduction rules are enough to produce the consequences of any set of axioms. It was a much more complex system than Enigma; the decoding procedure involved trying so many possibilities that it was impractical to do by hand.
Because the most complicated previous electronic device had used about valves, some were sceptical that the system would be reliable.
Flowers countered that the British telephone system used thousands of valves and was reliable because the electronics were operated in a stable environment with the circuitry on all the time.
The Bletchley management were not convinced and merely encouraged Flowers to proceed on his own.
This one could run four tapes and was used for running depths and "cribs" or known-plaintext attack runs. Here, in , Sale supervises the breaking of an enciphered message with the completed machine. With the highest priority for acquisition of parts, Flowers's team at Dollis Hill built the first machine in eleven months.
It was immediately dubbed 'Colossus' by the Bletchley Park staff for its immense proportions. The Mark 1 Colossus operated five times faster and was more flexible than the previous system, named Heath Robinson , which used electro-mechanical switches.