滚轮式加法器( 二 ) _生活百科

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A Pascaline, signed by Pascal in 1652Pascal began towork on his calculator in 1642, when he was only 19 years old. He had beenassisting his father, who worked as a tax commissioner, and sought to produce adevice which could reduce some of his workload. Pascal received a RoyalPrivilege in 1649 that granted him exclusive rights to make and sellcalculating machines in France.& nbsp; By 1652 Pascal claimed to have produced some fifty prototypes and sold justover a dozen machines, but the cost and complexity of the Pascaline—combined with the fact that it could only add and subtract, and the latter with difficulty—was a barrier to further sales, and production ceased in that year. By that time Pascal had moved on to other pursuits, initially the study ofatmospheric pressure, and later philosophy.

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Pascaline made for French currency.Pascalines camein both decimal and non-decimal varieties, both of which exist in museumstoday. The contemporary French currency system was similar to the Imperialpounds ("livres"), shillings ("sols") and pence("deniers") in use in Britainuntil the 1970s.In 1799 France changedto a metric system, by which time Pascal's basic design had inspired other craftsmen,although with a similar lack of commercial success. Child prodigy GottfriedWilhelm Leibniz devised a competing design, the Stepped Reckoner, in 1672 whichcould perform addition, subtraction, multiplication and division; Leibnizstruggled for forty years to perfect his design and produce sufficientlyreliable machines. Calculating machines did not become commercially viableuntil the early 19th century, when Charles Xavier Thomas de Colmar'sArithmometer, itself using the key break through of Leibniz's design, wascommercially successful.The initialprototype of the Pascaline had only a few dials, whilst later productionvariants had eight dials, the latter being able to deal with numbers up to9,999,999.

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开盖概览The calculatorhad spoked metal wheel dials, with the digit 0 through 9 displayed around thecircumference of each wheel. To input a digit, the user placed a stylus in thecorresponding space between the spokes, and turned the dial until a metal stopat the bottom was reached, similar to the way a rotary telephone dial is used.This would display the number in the boxes at the top of the calculator. Then,one would simply redial the second number to be added, causing the sum of bothnumbers to appear in boxes at the top. Since the gears of the calculator onlyrotated in one direction, negative numbers could not be directly summed. Tosubtract one number from another, the method of nines' complements was used. Tohelp the user, when a number was entered its nines' complement appeared in abox above the box containing the original value entered.