Published May 23, 2010 | 
A computer is a machine that calculates or assist in the calculation of all or any part of a mathematical problem, such as add, subtract, divide or multiply. All computers in this era were purely mechanical, such as electronics was unknown.
The varieties of old computers
The old computers are different forms in the early days, like the abacus, log tables, slide rule, etc., until a German professor named Wilhelm Schickard in 1623 built a gear driven machine to calculate and has called “Calculating Clock”. Later, in 1642, Blaise Pasc
al, a child prodigy, a great mathematician and physicist of France invented the Pascaline to his father in the calculation of tax assistance, because he was a tax collector. A few years after a German Pascal, Gottfried Wilhelm Leibniz built a four-function calculator “Stepped Reckoner”. Instead of gear he used drums ten fluted with flutes arranged on the surface of the “battery could be strengthened by adopting the decimal system of this unit. In recent decades, many attempts have been made for more support the operation of the computer to improvise, which are mainly used for mechanical and electro in the 18th and 19th centuries, a large amount of floor space occupied by a weight in tons.
Before the change of hundreds of computers of various capacities have been manufactured between 1939 and 1970. The transition from mechanical to electro-mechanical to electronic computers has taken decades, but increased exponentially to the current situation in the last two decades.
