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Lecture 5

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York University
Natural Science
NATS 1700
Zbigniew Stachniak

Lecture 5 - The Dawn of Automatic Computing - By the 1930s, mechanical and electromechanical calculators from Burroughs, Felt & Tarrant, Marchant, Monroe, Remington, Victor, and other manufacturers had all aspects of modern office operations. - Due to newer complex operations, such as solving linear equalities, differential equations, etc. could be found using a newer and more highly developed calculating machine with error free and predefined sequence of operations, that is, by following a program. - *The 1930s was a crucial period in the development of computing. o Newer designs of computers started to appear in Europe and US. o Ground breaking theoretical research on computing was initiated. - Alan Turing: A British mathematician, logician, cryptanalyst whose contributions to the science of computing were not only large in scope but also groundbreaking. o Best known for his outstanding contributions to cryptography during WWII when at Bletchley Park, he (and others) worked successfully on breaking German ciphers. o Using his amazing mathematics of computing he created the first ever general-purpose and universal computer out of a few symbols written on a piece of paper. In honor of its inventor, that device is now called the Turing Machine. (Published his results in 1936-37) o Did his groundbreaking research on ”abstract” computing machines at a time when there were no ”real” computers. - In 1928, David Hilbert suggested that the entire mathematics could be ”mechanized”. - According to Hilbert, some sort of an algorithm-following calculating machine and the job of a mathematician would be to discover the appropriate algorithms. - In 1936, Turing published a paper ”On Computable Numbers, with an Application to the Entscheidungsproblem” (Decision Problem). o In this paper Turing said there are mathematical problems that are unsolvable and could not be solved in an algorithmic way as envisioned by Hilbert. o To prove his result Turing designed an abstract computer – a simple mathematical concept but a powerful computing device. o Turing machines had helped to define and understand the notions fundamental to computing such as an algorithm, a computer, a computation and its complexity. - Automatic Computing in the 1930s, 40s, and 50s o A computer is a calculating device that is program- controlled; in other words, a computer performs operations by executing instructions arranged in a predefined way specified by the so-called program. o The earliest computers ever designed and built could be better classified as programmable calculators than computers as they were not designed to be general- but special-purpose devices. - Possibly the world’s earliest programmable calculating machine ever built was the Z1, designed and completed by the German engineer Konrad Zuse between 1936 and 1938 -- The computer was mechanical but powered by electricity. o It was unreliable and suffered from the same problems as early mechanical calculators: o Between 1938 and 1941, Zuse worked on improving his Z1 and came out with his Z3 computer which instead of mechanical components that he used to implement the processor of the Z1, his Z3 computer used electro- magnetic relays readily available from the telephony industry. - Both the Z1 and Z3 were destroyed during the WW2. o After the war, Zuse continued his work on computers by building other electromechanical machines–the Z4 (1950)–and his first electronic computer –Z22–that used vacuum tubes instead of electro-magnetic relays. Since 1955, a number of Z22s were manufactured. - The Colossus Mark-1 (1943) and Mark-2 (1944) calculating machines were designed by Tommy Flowers and built at the Post Office Research Lab in London to help with the war effort in decoding intercepted German telegraphic messages. - The computers were designed for one purpose only – to help with deciphering codes (hence, they were ”special-purpose”). And these computers were programmed by interconnecting various hardware modules with wires and by using switches (hence, they were not of ”stored- program” type). - After the war, all machines were dismantled by 1960 and all documentation destroyed. The computer was ”rediscovered” in the 1970s and reconstructed in the 1990s. - Significance of the Colossus computers: o The results obtained with the help of the Colossus computers gave Allied forces vital information prior to D Day (e.g. that all efforts to deceive Germans about place and direction for invasion, etc. did work); o The construction and use of the Colossus machines trained the first
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