First US Digital Computer

[xoxoxoBruce]

Aiken-IBM Automatic Sequence Controlled Calculator Mark I.
Here is a detailed article detailing how it was built.

Commander Aiken modestly ascribes the conception of this device to his own laziness. He is a tall, blond, 42-year-old electrician and scholar. To finish high school, he had to take correspondence courses while employed nights by an Indianapolis power company as a switchboard attendant. This accounts for the construction of the calculator in the form of a switchboard. To complete his thesis for a doctor’s degree at Harvard, he had to make calculations that took him nearly a year. This accounts for his decision to see whether such a machine could not be built.

For two years, he did not mention his breath-taking idea to anyone. He had to convince himself first that it was feasible. Then, in 20 minutes, he interested an International Business Machines Corporation engineer in the idea. Clair D. Lake, a pioneer inventor of mechanisms for I.B.M., was put in charge of work on the plans. Three other I.B.M. experts, Frank E. Hamilton, Benjamin M. Durfee, and James W. Bryce, also became coinventors. It took the company six years and cost more than $250,000 to build the machine. I.B.M. then presented it to Harvard.

[MaggieL]

The first? Depends who you ask.

[xoxoxoBruce]

Wikipedia says so. :p

[MaggieL]

Originally Posted by xoxoxoBruce

Wikipedia says so. :p

I think the excuse is the "large-scale" and "automatic" clauses. The Mark I was indeed bigger than either Eniac or the ABC. But then it *was* made by IBM. :-)

Clearly not "the first US digital computer".

[xoxoxoBruce]

Atanasoff-Berry was an unreliable one trick pony.
They had some great ideas and a solid theoretical foundation, but for lack of expertise or maybe funding they couldn't pull it off before being called for the war effort.

There were several other similar machines around the world but they suffered the same limitations of being very specialized.

The Aiken-IBM was a full fledged computer that could handle any type of mathematical calculations.
IBM was hired as the contractor to build it because of their expertise in building business machinery (cash registers), but not because they knew anything about computers......that was all Aiken.

[MaggieL]

IBM knew about a bit more than cash registers (although Watson was of course a fugitive from NCR who had to leave because of anti-trust problems). Their work with Hollerith card machines is not to be neglected; it was a central part of the data processiong technology of the day. And if the ABC fails by being neither fully-programmable or Turing-complete, the Mark I was neither stored-program nor fully electonic.

Aiken even went so far as to tell the NBS (today NIST) that "..you should...stop this foolishness with Eckert and Mauchly". Perhaps his only saving Grace was Hopper...she was his first programmer. But by the time ENIAC became UNIVAC, she was working on "foolishness" for Eckert and Mauchly.

Originally Posted by Grace Hopper

I am pleased that history recognises the first to invent something, but I am more concered with the first person to make it work.