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.
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.
Right. The patent refers to "semi-permanent cable connections" between card reader, registers, and printer. Basically, you could load and dump parts of memory, in decimal. The registers were all decimal, and so were IBM tabulators, so the interface is mostly a set of relays. No sign of format conversion or alphabetic capability.
>as I understand it there was really only ONE up and running at that time in 1948
As a matter of interest, "that time" being April, it was only two months later in June that the Manchester Baby ran its first stored program.
jshier · · focus · HN ↗
ENIAC in Action: Making and Remaking the Modern Computer is an excellent summary of the initial design and redesign of the Eniac.
HarHarVeryFunny · · focus · HN ↗
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.
Animats · · focus · HN ↗
dTal · · focus · HN ↗
As a matter of interest, "that time" being April, it was only two months later in June that the Manchester Baby ran its first stored program.