1st Computer Generation

First Generation computers are characterized by the use of vacuum tubes. These vacuum tubes were used for calculation as well as storage and control. Later, magnetic tapes and magnetic drums were implemented as storage media. The first vacuum tube computer, ENIAC, was developed by US army ordinance to calculate ballistic firing tables in WWII. It had about 17 000 vacuum tubes. The machine weighed 30 tons, covered about 1000 square feet of floor, and consumed 130 or 140 kilowatts of electricity. The ENIAC's clock speed was about 100 kHz. In addition to ballistics, the ENIAC's field of application included weather prediction, atomic-energy calculations, cosmic-ray studies, thermal ignition, random-number studies, wind-tunnel design, and other scientific uses. No electronic computers were being applied to commercial problems until about 1951.

•Vacuum tube technology

•Unreliable

•Supported Machine language only

•Very Costly

•Generate lot of heat

•Slow input / output device

E.g. : IBM-701 IBM 650