# Timeline of computing 750 BC-1949

 History of computing Before 1960 1960s to present Operating systems Timeline Timeline of computing 750 BC-1949 1950-1979 1980-1989 1990-

This article presents a detailed timeline of events in the history of computing from 750 BC until 1949. For a narrative explaining the overall developments, see the related history of computing.

Computing timelines: 750 BC-1949, 1950-1979, 1980-1989, 1990-present

## 750 BC-1799

 750 B.C. The abacus was first used by the Babylonians as an aid to simple arithmetic at sometime around this date. 87 BC The Antikythera mechanism: A clockwork, analog computer designed and built in Rhodes. The mechanism contains the first known differential gear and was capable of tracking the relative positions of all known heavenly bodies. 1492 Leonardo da Vinci produced drawings of a device consisting of interlocking cog wheels which could be interpreted as a mechanical calculator capable of addition and subtraction. A working model inspired by this plan was built in 1968 but it remains controversial whether Leonardo really had a calculator in mind [1] (http://dotpoint.com/xnumber/pic_leonardo_calc.htm). 1588 Logarithms are discovered by Joost Buerghi. 1614 Scotsman John Napier invents an ingenious system of moveable rods (referred to as Napier's Rods or Napier's bones). These were based on logarithms and allowed the operator to multiply, divide and calculate square and cube roots by moving the rods around and placing them in specially constructed boards. 1622 William Oughtred developed slide rules based on John Napier's logarithms. 1623 Wilhelm Schickard of Tübingen, Württemberg (now in Germany), built the first discrete automatic calculator, and thus essentially started the computer era. His device was called the "Calculating Clock". This mechanical machine was capable of adding and subtracting up to 6 digit numbers, and warned of an overflow by ringing a bell. Operations were carried out by wheels, and a complete revolution of the units wheel incremented the tens wheel in much the sameway counters on old cassette decks worked. Schickard was a friend of the astronomer Johannes Kepler since they met in the winter of 1617. Kepler used Schickard's machine for his astronomical studies. The machine and plans were lost and forgotten in the war that was going on, then rediscovered in 1935, only to be lost in war again, and then finally rediscovered in 1956 by the same man (Franz Hammer)! The machine was reconstructed in 1960, and found to be workable. 1642 French mathematician, Blaise Pascal built a mechanical adding machine (the "Pascaline"). Despite being more limited than Schickard's 'Calculating Clock' (see 1623), Pascal's machine became far more well known. He built around fifty, but was only able to sell around a dozen of his machines in various forms, coping with up to 8 digits. 1668 Sir Samuel Morland (1625-1695), of England, produces a non decimal adding machine, suitable for use with English money. Instead of a carry mechanism, it registers carries on auxiliary dials, from which the user must re-enter them as addends. 1671 German mathematician, Gottfried Leibniz designed a machine to carry out multiplication, the 'Stepped Reckoner'. It could multiply numbers of up to 5 and 12 digits to give a 16 digit result. The machine was later lost in an attic until 1879. Leibniz most important contribution to the computing era, however, was the binary number system which is used in all modern machines. He also co-invented calculus. 1726 Johnathan Swift describes (satirically) a machine ("engine") in his Gulliver's Travels. The "engine" consists of a wooden frame with wooden blocks containing parts of speech. When the engine's 40 levers are simultaneously turned, the machine displays grammatical sentence fragments. 1774 Philip Matthaeus Hahn, somewhere in what will be Germany, also makes a successful multiplying calculator. 1775 Charles Stanhope, 3rd Earl Stanhope, of England, makes a successful multiplying calculator similar to Leibniz's. 1784 Johann H. Müller, of the Hessian army, conceives the idea of what came to be called a "difference engine". That's a special-purpose calculator for tabulating values of a polynomial, given the differences between certain values so that the polynomial is uniquely specified; it's useful for any function that can be approximated by a polynomial over suitable intervals. Müller's attempt to raise funds fails and the project is forgotten.

## 1940-1949

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