History and Generations of Computers

By Georgia Alton, eHow Contributor

Although the computer is a 20th-century invention, its predecessors reach as far back as the 17th century. Computers have undergone four generations of development, with the first computers of the 1940s launching the first generation. Each generation of computer has become smaller, more versatile and more powerful. The most recent generation resulted in the rise of the personal computer, ushering in the information age.

Precursors

1. Historians of science see the abacus, first invented in Babylon in the 300s B.C.E., as a predecessor of the computer. In the modern era, William Schickland designed a mechanical calculator in 1623, a design which Blaine Pascal improved two decades later. Charles Babbage in England came up with the concept of a steam-powered calculating machine (the analytical machine) in the mid-1800s, but he failed to convince the British government to finance the project.

The First Electronic Computer

2. The British government built an electronic computing device during World War II (1939-1945 in England) to break the German's Enigma code. It was called Colossus, and the Americans followed the British with a computer a few years later, known as the Electronic Numerical Integrator Analyzor and Computer (ENIAC). The ENIAC is generally considered the first electronic computer because of the Colossus's limited computational ability. Scientists at the Ballistics Research Laboratory and the University of Pennsylvania designed and built the ENIAC on commission from the U.S. army to help formulate ballistics data for use in bombings and artillery.

Generations

3. The ENIAC represents the first generation of computers. Vacuum tubes composed the circuitry of computers like ENIAC; input to the computers was in the form of a punch card or magnetic tape, and output was in the form of print-outs. The invention of the transistor, which was a much smaller form of circuitry that used less power, ushered in the second generation of computers during the 1950s. The second generation of computers used programming languages like FORTRAN and COBOL, although the operating system had not yet been developed.

Development of the Operating System

4. In the mid-1960s, the integrated circuit replaced the transistor, which led, once again, to smaller and more powerful computers. During this third generation of computers, programmers developed more computer languages, like BASIC, C and Pascal. IBM OS/360 and UNIX debuted as the first operating systems. The development of the operating system, which standardized computer operations, led to the growth of commerical applications.

Information Age

5. The microprocessor inaugurated the fourth generation of computers. The integrated circuit had miniaturized the circuitry of a computer, but the microprocessor was a small chip that contained all of the basic functions of a computers (processing, memory and input/ouput). Intel introduced the first microprocessor in 1980--the Intel 4004. The reduction of size made possible by the microprocessor permitted the building of smaller computers, leading directly to the personal computer that dominates today as well as the Information Age.