Monday, June 6, 2011

The Eniac

It is actually a little hard to determine precisely what was the first modern computer. Computing machines were in use middle 1800's. These machines had some aspects of a modern computer, but the computations were done mechanically, not electrically. Also, player pianos have some attributes of a modern computer. 

It is generally agreed, however, that the first modern computer would be the Eniac machine, developed by the army in the 1940's. The army needed a way to more efficiently calculate balistic tables for artillery.

Modern computers work by basically cleverly configuring a series of on off switches to do useful computations. Prior to the development of the solid state transistors, the fundamental "switch" that was used was a vacuum tube. The Eniac machine used vacuum tubes as the switches. It had over 17,000 vacuum tubes, over 5,000,000 hand soldered joints, weighed 30 tons, and occupied over 1,800 square feet. Interesting to note that many of today's pocket calculators have more computation power than this machine.

Vacuum tubes were prone to failure, so it turned out that the machine would be down every day or two because of a burned out tube.

As it turned out, I don't believe the machine was ever used to calculate ballistic tables. The physicists on the Manhattan Project heard about the machine, and then took most of the time on it in developing the Atom Bomb.


  1. What & when was the first home computers? I remember Commodores & KayPros.

  2. You could actually get some exercise working at the computer at that time!

  3. next time you visit A WW2 era battle ship check out the computer room its pretty amazing

  4. The Yorktown has a 1970's retrofitted computer room - pretty neat.

    Ballistics tables were calculated by lining up rows of women in school desks with mechanical calculators and breaking the problem into parallel lines. The paper tapes were collected, collated, re-checked, and published.

    Like building a dam using shovels...


  5. The first computers I used had drum storage and core memory. Oh, and lots and lots of Hollerith cards.

    We even used analog computers a bit. Yep, I said analog -- programmed with patch cords and patch panels.

  6. Amazing how far and fast computers have come. In 79 I attended Wentworth Institute and the punch card was just on it's way out. In 84 I started a new job and the prize of the office was the IBM XT with 1 or 2 5 1/4" floppy's, 10 meg external hard drive. Latter we upgraded to the 20 meg hard drive. You could send a Telex on it! Cutting edge stuff. Everyone in the office wanted to use it. We were a start-up at the time so we could only afford 1 computer for the entire office. The XT is an antique, in my attic now.

  7. Last comment from Dave 107. I forgot to put my name on there.

  8. I still remember the quizzical expression on my boss' face while I tried to explain how having a video terminal (note: this is pre-PC days) on each person's desk was more efficient than standing in line to use one of the 3 terminals in the computer room on the other side of the building.

    Lear Sigler ADM-3 video terminals eventually made their way into our cubicles.

    Later, when PCs started to infiltrate, we had a similar discussion about another alien thing called 'ethernet' and how could it possibly make any sense at all to run network cables to our cubes.

  9. Long ago I had a coworker who collected slide rules. He had one that was used on the Manhattan Project. It is mind boggling to think how much of that work was done on slide rules! Now no one knows what they are.

  10. The first electronic digital computer was the Atanasoff-Berry Computer (ABC) developed at Iowa State University - prior to Eniac.

    Atanasoff couldn't seem to convince anyone of the value of it so it sat in a university basement for years.


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