Computer

The first use of the word "computer " was recorded in 1613, peferring to a person who carried out calculations, or computations, and the word continued to be used in that sense until the middle of the 20th century. From the end of the 19th century onwards though, the word began to take on its more familiar meaning, describing a machine that carries out cpmputations.

The history of the modern computer begins with two separate technologies-automated calculation and programmability but no single device can be identified as the rarliest computer, partly because of the inconsistent application of that term. Examples of rarly mechanical calculating fevices include the abacus, the slide ruke and arguably the astrolabe and the Antikythera mechanism. Hero of Alexandria built a mechanical theater which performed a play listing 10 minutes and was operated by a complex system of ropes and drums that might be considered to be a means of deciding which parts of the mechanism performed which actions ans when. This is the essence of programmability.

The "castle clock", an astronomical clock invented by Al-jazari in 1206, is considered to be the earliest programmable analot computer. It displayed the zodiac, the solar and lunar orbits, a crescent moon-shaped pointer travelling acress a gateway causing automatic doors to open every hour, and five ronotic musicians who played music when struck by levers operated by a camshaft attached to a wate wheel. The length of day and night could be re-programmed to compensate for the changing lengths of day and night throughout the year.

In 1801, Joseph Marie Jacquard made an improvement to the textile loom by introducing a series of punched paper cards as a templates which allowed his loom to weave intricate the use of punched cards to define woven patterns can be viewed as an early,albeit limited, form of programmability.

It was the fusion of automatic calculation with programmability that produced the first recognizable computers.In1837, charles Babbage was the first to conceptualize and design a fully programmable mechanical computer, his analytical engine.Linited finances and Babbage's inability to resist tinkering with the design meant that the device was never completed.