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Text 1 Mechanical calculators Part 1



 

Circa 4000 B.C. One of the earliest known computational devices, the abacus, was developed. This is a mechanical device composed of a slab (abax in Greek) with pebbles (calculi in Greek) strung on wires. The position of the pebbles on each wire determines the value of a digit. The abacus (also known as the Chinese suan pan and the Japanese soroban) can be used to add, subtract, multiply, and divide. In the hands of a skilled operator, it can produce results as fast as a modern desktop calculator.

1623. Machines capable of automatically performing the four basic arithmetic operations first appeared in Europe in the early seventeenth century. The earliest such machine seems to have been designed and built in 1623 by Wilhelm Schickhard at the University of Tubingen. Schickhard's machine was little known in his day.

1645. Blaise Pascal, the French philosopher, mathematician, and physicist, developed the first real mechanical calculator. This was a rotating wheel that used a series of eight gears with automatic carry generation between digits for addition and subtraction of decimal numbers.

Mid-1600s. John Napier, a Scot, invented the concept of logarithms and implemented it on a set of ivory rods, known as Napier's bones, which were used to perform multiplication and division through repeated additions and subtractions.

Circa 1650. Robert Bissaker extended Napier's work with logarithms and invented the slide rule, using sliding pieces of wood.

1671-1694. The Prussian mathematician Baron Gottfried Wilhelm von Leib­niz extended Pascal's adding machine to perform multiplication and division through the use of additional gears.

1725. Basile Bouchon introduced a simple draw-loom for weaving figured silks. The silk designs were controlled by patterns of holes punched on a roll of paper. When the coded paper was pressed against a row of needles, those that lined up with the holes remained in place while the others moved forward. The loom's action, controlled by the selected needles, formed the pattern of the fabric.

1741. A watchmaker named Jacques de Vaucanson built an automatic loom for weaving figured silks. The designs were established by patterns of holes punched on a metal drum. The holes controlled the selection of threads by raising and lowering the treadles.

1801. One of the interesting results of the industrial revolution was the Jacquard loom. Joseph Marie Jacquard, a silk weaver from France, built in 1801 an attachment to the weaving loom that resulted in automated pattern weaving. This was a step toward the development of programmable instructions since the loom was controlled by a series of punched cards. The cards had holes in them and functioned just like a program, providing sets of instructions that were read by the machines as they passed over a series of rods. By 1812 there were over 11,000 Jacquard looms in France.

1821. The next major advance is associated with the English inventor Charles Babbage. The device, called the difference engine, implemented finite difference operations. In 1854 a Swede named Georg Scheutz was able to build a working version of Babbage's difference engine.

Meanwhile, Babbage developed the idea of the analytical engine, which contained many features similar to twentieth-century stored-program digital computers. It was designed around two types of cards: operating cards, which indicated specific functions to be performed, and variable cards, which indicated actual data. The machine itself had a store – an area within the device in which instructions and variables were maintained - and a mill – an arithmetic unit that performed the operations. Instructions and data were fed into the device by means of punched cards, and output was produced automatically.




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