A quick review of ENIAC

Eniac

          The World War II gave birth to the ENIAC (Electronic Numerical Integrator Analyzer and Computer), which is built between 1943 and 1945 by the U.S. Army to produce missile trajectory tables. ENIAC performed 5,000 additions a second although a problem that took two seconds to solve required two days to set up.
          ENIAC cost $500,000, weighted 30 tons, and was 100 feet long and 8 feet high. It contained 1,500 relays and 17,468 vacuum tubes.
          Those  same tubes that made ENIAC possible in the first place, were also its Achilles' heel. Consuming 200 kilowatts of electricity each hour, the tubes turned the computer into an oven, constantly cooking its own components. Breakdowns were frequent. What was needed was something that did the job of the tubes without the heat, bulk, and fragility. And that something had been around 1926.

And then......

          In 1926 the first semiconductor transistor was invented, but it wasn't until 1947, when Bell Labs' William Shockley patented the modern solid state, reliable transistor, that a new era in computing dawned. The transistor did essentially the same thing a vacuum tude did. Even with the transistors, the few computers built then still used tubes. It wasn't until 1954, when Texas Instruments created a way to produce silicon transistors commercially, that the modern computer took off. That same year IBM introduced the 650, the first mass produced computer. Business and the Government bought 120 of them in the first year.
         

After the ENIAC.......

          The computer grew increasingly smaller and more powerful, but its cost, complexity, and unswerving unfriendliness kept it the tool of a technological  elite. It wasn't until 1975 that something resembling a personal computer appeared. The January issue of Popular Electronic features on its cover something called the Altair 8800, made by Micro Instrumentation and Telemetry Systems(MITS). For $367 customers got a kit that included and Intel 8080 microprocessor and 256 bytes of memory. There was no keyboard; programs and data were both entered by clicking switches on the front of the Altair. There was no monitor. Results were read by interpreting a pattern of small red lights. But it was a real computer cheap enough for anyone to afford. MITS got orders for 4,000 within a few weeks.....                                                          
Credit: Ron White

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