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A mechanical calculator, or calculating machine, was a mechanical device used to perform automatically the basic operations of arithmetic. Most mechanical calculators were comparable in size to small desktop computers and have been rendered obsolete by the advent of the electronic calculator. Surviving notes from Wilhelm Schickard in 1623 report that he designed and had built the earliest of the modern attempts at mechanizing calculation. His machine was composed of two sets of technologies: first an abacus made of Napier's bones, to simplify multiplications and divisions first described six years earlier in 1617, and for the mechanical part, it had a dialed pedometer to perform additions and subtractions. A study of the surviving notes shows a machine that would have jammed after a few entries on the same dial,〔Michael Williams, History of Computing Technology, IEEE Computer Society, p.122 (1997)〕 and that it could be damaged if a carry had to be propagated over a few digits (like adding 1 to 999).〔Michael Williams, History of Computing Technology, IEEE Computer Society, p.124,128 (1997)〕 Schickard abandoned his project in 1624 and never mentioned it again until his death eleven years later in 1635. Two decades after Schickard's failed attempt, in 1642, Blaise Pascal decisively solved these particular problems with his invention of the mechanical calculator.〔Prof. René Cassin, Pascal tercentenary celebration, London, (1942), Magazine Nature〕 Co-opted into his father's labour as tax collector in Rouen, Pascal designed the calculator to help in the large amount of tedious arithmetic required.;〔Jean Marguin (1994), p. 48〕 it was called Pascal's Calculator or Pascaline.〔See Pascal's calculator#Competing designs〕 Thomas' arithmometer, the first commercially successful machine, was manufactured two hundred years later in 1851; it was the first mechanical calculator strong enough and reliable enough to be used daily in an office environment. For forty years the arithmometer was the only type of mechanical calculator available for sale.〔Beside two arithmometer clone makers from Germany and England, the only other company to offer calculators for sale was Felt & Tarrant from the USA which started selling their comptometer in 1887 but had only sold 100 machines by 1890.〕 The comptometer, introduced in 1887, was the first machine to use a keyboard which consisted of columns of nine keys (from 1 to 9) for each digit. The Dalton adding machine, manufactured from 1902, was the first to have a 10 key keyboard.〔Ernst Martin p.133 (1925)〕 Electric motors were used on some mechanical calculators from 1901.〔Ernst Martin p.23 (1925)〕 In 1961, a comptometer type machine, the Anita mk7 from Sumlock comptometer Ltd., became the first desktop mechanical calculator to receive an all electronic calculator engine, creating the link in between these two industries and marking the beginning of its decline. The production of mechanical calculators came to a stop in the middle of the 1970s closing an industry that had lasted for 120 years. Charles Babbage designed two new kinds of mechanical calculators, which were so big that they required the power of a steam engine to operate, and that were too sophisticated to be built in his lifetime. The first one was an ''automatic'' mechanical calculator, his difference engine, which could automatically compute and print mathematical tables. In 1855, Georg Scheutz became the first of a handful of designers to succeed at building a smaller and simpler model of his difference engine.〔#MARG,Jean Marguin p. 171, (1994)〕 The second one was a ''programmable'' mechanical calculator, his analytical engine, which Babbage started to design in 1834 ; "in less than two years he had sketched out many of the salient features of the modern computer. A crucial step was the adoption of a punched card system derived from the Jacquard loom"〔Anthony Hyman, ''Charles Babbage, pioneer of the computer'', 1982〕 making it infinitely programmable.〔"The introduction of punched cards into the new engine was important not only as a more convenient form of control than the drums, or because programs could now be of unlimited extent, and could be stored and repeated without the danger of introducing errors in setting the machine by hand; it was important also because it served to crystallize Babbage's feeling that he had invented something really new, something much more than a sophisticated calculating machine." Bruce Collier, 1970〕 In 1937, Howard Aiken convinced IBM to design and build the ASCC/Mark I, the first machine of its kind, based on the architecture of the analytical engine;〔I. Bernard Cohen, p. 66-67, (2000)〕 when the machine was finished some hailed it as "Babbage's dream come true".〔Brian Randell, p.187, 1975〕 ==Ancient history== A short list of other precursors to the mechanical calculator must include a group of mechanical analog computers which, once set, are only modified by the continuous and repeated action of their actuators (crank handle, weight, wheel, water...). Before common era, there are odometers and the Antikythera mechanism, an out of place, unique, geared astronomical clock, followed more than a millennium later by early mechanical clocks, geared astrolabes and followed in the 15th century by pedometers ; These machines were all made of toothed gears linked by some sort of carry mechanisms. These machines always produce identical results for identical initial settings unlike a mechanical calculator where all the wheels are independent but are also linked together by the rules of arithmetic. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Mechanical calculator」の詳細全文を読む スポンサード リンク
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