Amita Vadlamudi - Computer Systems Engineer

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The Three Generations of Computers

on 10 Dec 2017 20:23 | Viewed 1075 times

Since the 1940’s three generations of computers have evolved, each powered by the vacuum tubes, transistors and microchips respectively.

First generation computers:

Vacuum tubes were invented in 1906 by the American physicist Lee De Forest. Vacuum tubes used electricity to heat a filament inside a tube.

ENIAC was the first significant computer to be built using the vacuum tubes. It was built in 1944 at University of Pennsylvania by two professors John Mauchly and J. Presper Eckert. Around 1950 Remington Rand built the UNIVAC for the US Census Bureau. Subsequently a number of UNIVAC computers were produced for business and government applications. IBM 650 which was smaller and more affordable computer was introduced in 1954.

Second Generation Computers:

Because of their large size, vacuum tubes required enormous amount of physical space. They also needed to be replaced often and were inefficient and expensive to operate.

The transistors which were invented in 1947 at the Bell Laboratories by William Shockley and John Bardeen solved the problems inherent in vacuum tubes. Transistors were much smaller, used less power, more reliable and lasted much longer. From 1955 onwards transistors replaced vacuum tubes in computers. The computers are now much smaller and less expensive to operate.

IBM 1401 was one of the major second generation computers to be built using the transistors.

Between 1960 and 1964 IBM produced and sold more than ten thousand 1401s.

Third Generation Computers:

Although they were major improvement over the vacuum tubes, transistors also had limitations. They needed to be soldered together. As the circuits became more complex, more connections between multiple transistors were needed increasing the risk of faulty wiring.

In 1958 the integrated circuit, known as the computer chip was created by Jack Kilby and Robert Noyce at Texas Instruments. The chip is a collection of tiny built-in transistors and it saved space and increased the process speed exponentially.

Beginning in 1960 computers migrated to the chip technology. IBM System/360 was one of the major mainframe computers to use the integrated circuit. Large mainframes became common in large businesses and with US military and space programs. The chip technology led to the development of microprocessor which in turn led to the development of the microcomputers that are small and affordable by individuals and small businesses. Beginning in mid-1970’s microcomputer explosion occurred leading to nearly every individual owning a personal computer or another electronic device such as the cell phone.

About the Author: Amita Vadlamudi has worked in the computer industry beginning in the early 1970’s. Amita Vadlamudi’s initial training in computer programming was done on IBM mainframes which took input and the instructions on punched cards, and printed the output on reamed paper. 


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