FIRST GENERATION OF COMPUTERS

FIRST GENERATION ESTABLISHED 1940-1956: VACUUM TUBES

The first generation of computers were vacuum tubes for circuitry and magnetic drums for memory, they were very expensive in operation, slow in operation and undependable, they were very big taken a whole room, they generate lots of heat which often cause malfunction.

In 1946 two Americans, Presper Eckert, and John Mauchly built the ENIAC electronic computer which used vacuum tubes instead of the mechanical switches of the Mark I.  The ENIAC used thousands of vacuum tubes, which took up a lot of space and gave off a great deal of heat just like light bulbs do.  The ENIAC led to other vacuum tube type computers like the EDVAC (Electronic Discrete Variable Automatic Computer) and the UNIVAC I (UNIVersal Automatic Computer).

        The vacuum tube was an extremely important step in the advancement of computers.  Vacuum tubes were invented the same time the light bulb was invented by Thomas Edison and worked very similar to light bulbs.  It's purpose was to act like an amplifier and a switch.  Without any moving parts, vacuum tubes could take very weak signals and make the signal stronger (amplify it).  Vacuum tubes could also stop and start the flow of electricity instantly (switch).  These two properties made the ENIAC computer possible.

        The ENIAC gave off so much heat that they had to be cooled by gigantic air conditioners.  However even with these huge coolers, vacuum tubes still overheated regularly.  It was time for something new.

CHARACTERISTICS:

(Not all first generation computers had all these characteristics)

vacuum tube based, punched tape input or output, about 1,000 circuits per cubic foot, Harvard Mark I (electromechanical), Whirlwind, ENIAC, EDSAC, UNIVAC I, UNIVAC II, UNIVAC 1101, RCA BIZMAC, NCR CRC 102A, NCR CRC 102D, Honeywell Datamatic 1000, Burroughs E101, Burroughs 220, IBM models 604, 650 (drum memory), 701, 702, 704, 705, 709