Babbage's Analytical Engine
In 1832, an English inventor and mathematician Charles Babbage was commissioned by the British government to develop a system for calculating the rise and fall of the tides.
Babbage designed a device and called it an analytical engine. It was the first programmable computer, complete with punched cards for data input. Babbage gave the engine the ability to perform different types of mathematical operations. The machine was not confined to simple addition, subtraction, multiplication, or division. It had its own "memory", due to which the machine could use different combinations and sequences of operations to suit the purposes of the operator.
The machine of his dream was never realized in his life. Yet Babbage's idea didn't die with him. Other scientists made attempts to build mechanical, general-purpose, stored-program computers throughout the next century. In 1941 a relay computer was built in Germany by Conrad Zuse. It was a major step toward the realization of Babbage's dream.
The Mark I Computer (1937-1944)
In 1944 in the United States, International Business Machines (IBM) built a machine in cooperation with scientists working at Harvard University under the direction of Prof. Aiken. The machine, called Mark I Automatic Sequence-Controlled Calculator, was built to perform calculations for the Manhattan Project, which led to the development of atomic bomb. It was the largest electromechanical calculator ever built. It used over 3000 electrically actuated switches to control its operations. Although its operations were not controlled electronically, Aiken's machine is often classified as a computer because its instructions, which were entered by means of a punched paper tape, could be altered. The computer could create ballistic tables used by naval artillery.
The relay computer had its problems. Since relays are electromechanical devices, the switching contacts operate by means of electromagnets and