Comment by jshier
3 hours ago
I'm pretty sure Kay's not quite correct about the Eniac not being a stored program computer. In it's original form it obviously was not, as it had to physically reconfigured to solve different problems. However, after the war it was rebuilt to operate like any other stored program (von Neumann architecture) computer, as it was the first recipient of the design philosophy seen in the EDVAC report. It operated in that mode from '48 to '55, when it was decommissioned.
ENIAC in Action: Making and Remaking the Modern Computer is an excellent summary of the initial design and redesign of the Eniac.
Apparently Eckert (John Mauchly and J. Presper Eckert designed the ENIAC) claimed that von Neumann basically stole their idea of the stored program and that they had already came up with the idea and he just took it and ran with it as if it was his
> And John Von Neumann? He came and looked at our stuff and went back to Princeton and wrote a long document about the principles. He gets a lot of credit but the inventions were ours. Someday I’ll write a book on who really invented the computer.
>Johnny learned instantly, of course, as was his nature. But he chose to refer to the modules we had described as “organs” and to substitute hypothetical “neurons” for hypothetical vacuum tubes or other devices which could perform logical functions. It was clear that Johnny was rephrasing our logic, but it was still the SAME logic. Also, he was introducing different but equivalent symbols; nevertheless the devices still did the same things. Johnny did NOT alter the fundamental concepts which we had already formulated for the EDVAC.
>Small wonder, then, that computer history gave von Neumann the credit. Eckert and I, who left the Univ. of Penna. In 1946, no longer had access to the documents which might have helped to show “who did what, when.” But after many years, litigation has unearthed some of those documents, and historians can read what was once classified. But, even after declassification, those reports are not accessible to most people, since they were reproduced in such small quantities. Nevertheless, we hope that more historians will refer to them.
Eckert and Mauchly weren't reliable narrators of the history of their work, given how much they needed to claim in order to get the patents that were later invalidated. They claimed quite a few things that were later disproven in court or through historical study. At the least, Eniac was designed by the team at the Moore School.
von Neumann's "First Draft of a Report on the EDVAC" was both a summary of discussions by the Eniac team as well as von Neumann's own original work proving and expanding on various aspects of those discussions. It's called the von Neumann architecture because he was the author of the seminal paper, not because he laid any particular claim to the ideas. Eckert and Mauchly were mostly upset about the paper's existence, regardless of author, because it made it impossible for them to patent the stored program idea in general.
Saying "like any other stored program computer" makes it sound like there were a bunch of them, but as I understand it there was really only ONE up and running at that time in 1948 - IBM's SSEC. The stored program EDVAC, whose architecture Von Neumann had formalized, was still not yet running, and Von Neumann personally advised on adapting ENIAC to this mode of operation.
As I understand it, even after adaptation to "stored program" mode, the program was still configured rather than loaded and stored, but now configuration was done using the function table dials (essentially a dedicated dial for each program step) rather than patch cords, and was a lot more convenient. Punched cards could be used for reading/writing data, but not for programs.
It seems there was no BIOS because I/O was so primitive. Per configuration a punched card would be read into the "constant transmitter" unit, then one of the read numbers could be copied into one of the 20 accumulators. Or you could do the same in reverse to output data from the accumulators.