Mechanical (Edited from Wikipedia)

SUMMARY

A , or calculating , was a mechanical device used to automatically perform the basic operations of . Most mechanical were comparable in size to small desktop 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 . His machine was composed of two sets of : first an made of Napier's bones, to simplify and divisions. And for the mechanical part, it had a dialed pedometer to perform and . A study of the surviving notes shows a machine that would have jammed after a few entries on the same dial, and that it could be damaged if a carry had to be propagated over a few digits (like adding 1 to 999). 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. Helping his father as tax collector in , Pascal designed the calculator to help in the large amount of tedious arithmetic required.; it was called Pascal's Calculator or Pascaline.

Thomas' , 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.

The , 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. Electric motors were used on some mechanical calculators from 1901.

In 1961, a comptometer type machine, 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

1 calculators came to a stop in the middle of the 1970s closing an industry that had lasted for 120 years.

HISTORY

The abacus, also called a counting frame, is a calculating tool that was in use in Europe, China and , centuries before the adoption of the written Hindu–Arabic system and is still used by merchants, traders and clerks in some parts of Eastern Europe, Russia, China and Africa. Today, they are often constructed as a frame with beads sliding on wires, but originally they were beans or stones moved in grooves in sand or on tablets of wood, stone, or metal.

During the , around 600 BC the Persians first began to use the abacus. Under the Parthian, Sassanian and Iranian empires, scholars concentrated on exchanging knowledge and inventions with the countries around them – , China, and the , when it is thought to have been exported to other countries.

The normal method of calculation in ancient Rome, as in Greece, was by moving counters on a smooth table. Originally pebble were used. They were later manufactured in medieval Europe. Marked lines indicated units, fives, tens etc. as in the Roman . This system of 'counter casting' continued into the late Roman empire and in medieval Europe, and persisted in limited use into the nineteenth century.

Due to Pope Sylvester II's reintroduction of the abacus with very useful modifications, it became widely used in Europe once again during the This abacus used beads on wires, unlike the traditional Roman counting boards, which meant the abacus could be used much faster.

Over centuries, support for arithmetical operations was provided either by the abacus or by other counting technologies such as the counting board. In 1617 John Napier built on a known method of "lattice " to publish his "rods" or Napier's Bones. They appeared in a range of forms over subsequent centuries. They made it much easier to do multiplication and , especially by those not well equipped to memorize multiplication tables.

A short list of other precursors to the mechanical calculator must include the Greek from around 100 BC. It was an out of place, unique, geared mechanism. It was followed more than a millennium later by early mechanical and geared . These were all made of toothed linked by some sort of carry mechanisms. They belong to a group of mechanical analog computers

2 which, once set, are only modified by the continuous and repeated action of their actuators (crank handle, weight, wheel...)

Some measuring instruments and automatons were also precursors to the calculating machine. In 1525, the French craftsman Jean Fernel built the first pedometer. It was made in the shape of a watch and had four dials (units, tens, hundreds, thousands) linked by a single-tooth carry mechanism.

The marked the beginning of the history of mechanical calculators, as it saw the invention of its first machines, including Pascal's calculator, in 1642. Blaise Pascal had invented a machine which he presented as being able to perform computations that were previously thought to be only humanly possible, but he wasn't successful in creating an industry.

PASCAL’S CALCULATOR

Blaise Pascal invented a mechanical calculator with a sophisticated carry mechanism in 1642. Pascal was led to develop a calculator by the laborious arithmetical required by his father's work as supervisor of taxes. After three years of effort and 50 prototypes he introduced his calculator to the public. He built twenty of these machines in the following ten years. This machine could add and subtract two numbers directly and multiply and divide by repetition.

Pascal's calculator was especially successful in the design of its carry mechanism, which adds 1 to 9 on one dial, and when it changes from 9 to 0, carries 1 to the next dial. His innovation made each digit independent of the state of the others, which enabled multiple carries to rapidly cascade from one digit to another regardless of the machine's capacity. Pascal was also the first to shrink and adapt for his purpose a lantern , used in turret clocks and water wheels, which could resist the strength of any operator input with very little added friction.

Since, unlike Schickard's machine, the Pascaline dials could only rotate in one direction, zeroing it after each calculation required the operator to dial in all 9s and then propagate a carry right through the machine. This suggests that the carry mechanism would have proved itself in practice many times over. This is a testament to the quality of the Pascaline because none of the 17th and 18th century criticisms of the machine mentioned a problem with the carry mechanism and yet it was fully tested on all the machines, by their resets, all the time.

3 The calculator had spoked metal wheel dials, with the digit 0 through 9 displayed around the circumference of each wheel. To input a digit, the user placed a stylus in the corresponding space between the spokes and turned the dial until a metal stop at the bottom was reached, similar to the way a rotary telephone dial is used. This displayed the number in the windows at the top of the calculator. Then, one simply redialed the second number to be added, causing the sum of both numbers to appear in the accumulator.

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