The First Transistorized Computer


January, 1954:

If transistors could replace vacuum tubes in the phone system, then they certainly could replace them in computers too.  The army, with its need for ever-faster and more efficient calculations, was the first to jump on the bandwagon.  The advantages of transistors over vacuum tubes were many -- not only were they smaller and quicker, but they used next to no power compared to vacuum tubes.  (The vacuum tube-powered ENIAC, for example, reportedly caused brownouts in Philadelphia whenever it was turned on.) Transistors also flipped on instantaneously, compared to sluggish vacuum tubes, which took several seconds to warm up. 

Transistors, unfortunately, were substantially more expensive than vacuum tubes -- costing $20 as compared to $1 for a vacuum tube -- but the advantages still outweighed that one drawback. In January of 1954, supported by the military, engineers from Bell Labs built the first computer without vacuum tubes.  Known as TRADIC (for TRAnsistorized DIgital Computer), the machine was a mere three cubic feet, a mind-boggling size when compared with the 1000 square feet ENIAC hogged. It contained almost 800 point-contact transistors and 10,000 germanium crystal rectifiers.  It could perform a million logical operations every second, still not quite as fast as the vacuum tube computers of the day, but pretty close.  And best of all, it operated on less than 100 watts of power. 

-- Crystal Fire by Michael Riordan and Lillian Hoddeson  
-- History of Computers 

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