Contents

In 1948, Turing was appointed reader in the Mathematics Department at the Victoria University of Manchester. A year later, he became deputy director of the Computing Machine Laboratory, where he worked on software for one of the earliest stored-program computers—the Manchester Mark 1. Turing wrote the first version of the Programmer’s Manual for this machine, and was recruited by Ferranti as a consultant in the development of their commercialised machine, the Ferranti Mark 1. He continued to be paid consultancy fees by Ferranti until his death.

Turing’s legacy continues to have an impact on both science and society today. “He was also gay, and was treated appallingly as a result. By placing him on our new polymer How to Become a Software Engineer Without a CS Degree in 2022 £50 banknote, we are celebrating his achievements, and the values he symbolises.” Turing was granted a royal pardon in 2013 for his 1952 conviction for gross indecency.

## Turing machine

His paper on this theory, completed in 1951, became a classic and is still the subject of intense investigation 60 years later. In the same year he was elected a Fellow of the Royal Society for his earlier work. After two years at Princeton, developing ideas about secret ciphers, Turing returned to Britain and joined the government’s code-breaking department.

Post’s Turing machine has only one kind of symbol and so does not rely on the Turing system of F andE-squares. Note that \(T_\) will never enter a configuration where it is scanning \(S_1\) so that two of the four quintuples are redundant. Another typical format to represent Turing machines and which was also used by Turing is the transition table. Note that in its original form (Hilbert & Ackermann 1928), the problem was stated in terms of validity rather than derivability.

Similarly, the transition 1Lq2 implies that the write symbol is 1, the tape moves left, and the next state is q2. Non-erasing machines are machines that can only overprint \(S_0\). In Moore 1952, it was mentioned that Shannon proved that non-erasing machines can compute what any Turing machine computes.

## Post as a guest

This small defect was corrected by Post by including an additional instruction in the function used to mark the complete configuration in the next round. \(\textrm\_\textrm\) The machine compares the sequences A and B marked with a and brespectively. If A and B are equal, all a’s andb’s will have been erased and the machine moves to state \(q_j\), else, it will move to state \(q_n\).

- The alphabet contains a special blank symbol (here written as ‘0’) and one or more other symbols.
- If A and B are equal, all a’s andb’s will have been erased and the machine moves to state \(q_j\), else, it will move to state \(q_n\).
- Belousov was not aware of Turing’s paper in the Philosophical Transactions of the Royal Society.

In some models, if there is no entry in the table for the current combination of symbol and state, then the machine will halt; other models require all entries to be filled. A Turing machine is a mathematical model of computation describing an abstract machine that manipulates symbols on a strip of tape according to a table of rules. Despite the model’s simplicity, it is capable of implementing any computer algorithm. After the war, Turing continued to develop his ideas about computer science.

## Artificial intelligence (AI)

In 1938, he obtained his PhD from the Department of Mathematics at Princeton University. During the Second World War, Turing worked for the Government Code and Cypher School (GC&CS) at Bletchley Park, Britain’s codebreaking centre that produced Ultra intelligence. For a time he led Hut 8, the section that was responsible for German naval cryptanalysis. Here, he devised a number of techniques for speeding the breaking of German ciphers, including improvements to the pre-war Polish bomba method, an electromechanical machine that could find settings for the Enigma machine. Turing played a crucial role in cracking intercepted coded messages that enabled the Allies to defeat the Axis powers in many crucial engagements, including the Battle of the Atlantic. Besides the Turing machine, several other models were introduced independently of Turing in the context of research into the foundation of mathematics which resulted in theses that are logically equivalent to Turing’s thesis.

If A and B then diffused through the container at different rates, then you could have some regions where A dominated and some where B did. To calculate the extent of this, Turing would have needed a powerful computer, but these were not so freely available in 1951, so he had to use linear approximations to solve the equations by hand. These calculations gave the right qualitative results, and produced, for example, a uniform mixture that oddly enough had regularly spaced fixed red spots. The Russian biochemist Boris Belousov had performed experiments with similar results, but could not get his papers published because of the contemporary prejudice that any such thing violated the second law of thermodynamics. Belousov was not aware of Turing’s paper in the Philosophical Transactions of the Royal Society. Although ACE was a feasible design, the effect of the Official Secrets Act surrounding the wartime work at Bletchley Park made it impossible for Turing to explain the basis of his analysis of how a computer installation involving human operators would work.

There code-breaking became an industrial process; 12,000 people worked three shifts 24/7. Although the Polish had cracked Enigma before the war, the Nazis had made the Enigma machines more complicated; there were approximately possible permutations. Turing designed an electromechanical machine, called the Bombe, that searched through the permutations, and by the end of the war the British were able to read all daily German Naval Enigma traffic.

## Alan Turing: Creator of modern computing

Turing’s contributions to the modern world were not merely theoretical. During the second world war, he worked as a codebreaker for the UK government, attempting to decode the Enigma cipher machine encryption devices used by the German military. At the bill’s second reading in the House of Commons on 29 November 2013, Conservative MP Christopher Chope objected to the bill, delaying its passage.

## Small Turing machines

Turing attacked the problem by imagining a machine with an infinitely long tape. The tape is covered with symbols that feed instructions to the machine, telling it how to manipulate other symbols. This universal Turing machine, as it is known, is a mathematical model of the modern computers we all use today.

Homosexual acts were criminal offences in the United Kingdom at that time, and both men were charged with “gross indecency” under Section 11 of the Criminal Law Amendment Act 1885. Initial committal proceedings for the trial were held on 27 February during which Turing’s solicitor “reserved his defence”, i.e., did not argue or provide evidence against the allegations. In 1948, Turing, working with his former undergraduate colleague, D.G. Champernowne, began writing a chess program for a computer that did not yet exist.

The idea was that a computer could be said to “think” if a human interrogator could not tell it apart, through conversation, from a human being. In the paper, Turing suggested that rather than building a program to simulate the adult mind, it would be better https://cryptominer.services/ to produce a simpler one to simulate a child’s mind and then to subject it to a course of education. A reversed form of the Turing test is widely used on the Internet; the CAPTCHA test is intended to determine whether the user is a human or a computer.

His main theme had been in investigating the power of a computer to rival human thought. In 1950, he published a philosophical paper including the idea of an ‘imitation game’ for comparing human and machine outputs, now called the Turing Test. This paper remains his best known work and was a key contribution to the field of Artificial Intelligence. Turing analysed what it meant for a human to follow a definite method or procedure to perform a task.