1948 ENIAC

[dbrll]

Hi,

From the README:

Future plans include implementing the enhancements that were made at the Ballistics Research Lab during its operational life.

I assume this means implementing the 1948 "Von Neuman" ENIAC? Are there any wiring diagrams available for this re-implementation, and specifications for the new converter unit? The ENIAC was a stored program computer for most of its 11 years life, yet it's mostly only remembered as it was in its early days. Emulating its 1948 implementation and maybe its later additions such as core memory would be a first, and would bring historical recognition to this machine which ran its first stored program one month before the SSEM. I'm definitely looking forward to seeing this.

By the way, since the simulator goes down to the pulse level, may we also assume it would be feasible to display a view of the Cycling Unit oscilloscope, and enjoy watching the pulses traveling through the machine? I believe this would be another first in a low level emulator.

[dbrll]

Addendum: I probably didn't spend enough time researching the topic before posting this enhancement suggestion. The 1948 configuration has been indeed documented, and I read Mark Priestley developed an emulator for it, although I'm not quite sure it was made publicly available. I wasn't aware of this until I read your "Simulating the ENIAC" article more thoroughly.

[blstuart]

So the full story as I know it so far includes at least three different designs for the stored program type operation.  The first one is fairly sketchy, but would run on the original machine with no changes.  The second was an intermediate one that required the converter unit as did the one actually deployed.  I've found some pretty complete records of the middle one, and as you noted, Haight, Priestly, and Rope have found the later one.  So one of my objectives is to implement all three, and of course, that will require adding the converter unit to the simulator. After the initial deployment of the 1948 configuration, there were additional enhancements made before its retirement in 1955, including a shifter unit and a core memory unit.  Those are also on my radar to add to the simulator when I get a chance.

As for the scope on the cycleing unit, yes, I don't really see any reason why I couldn't add a clock trace to the display.  From what I can tell from the documentation, the way it worked was that there was a switch on the cycling unit panel that allowed you to select which of the clock signals was displayed on the scope.  So I'm pretty sure you only got to see one of them at a time.  Maybe what I should try to do is add a button on the cycling unit when it's displayed straight on and use that to select which clock signal to draw on the screen.

Even more fun could be a scope that the user could "plug" into any trunk line and display the signal on that line.  I'll have to give that some thought.

Thanks, BLS

On Thursday, February 10, 2022, 12:29:25 AM UTC, kehak @.***> wrote:

Hi,

From the README:

   Future plans include implementing the enhancements that were made at the Ballistics Research Lab during its operational life.

I assume this means implementing the 1948 "Von Neuman" ENIAC? Are there any wiring diagrams available for this re-implementation, and specifications for the new converter unit? The ENIAC was a stored program computer for most of its 11 years life, yet it's mostly only remembered as it was in its early days. Emulating its 1948 implementation and maybe its later additions such as core memory would be a first, and would bring historical recognition to this machine which ran its first stored program one month before the SSEM. I'm definitely looking forward to seeing this.

By the way, since the simulator goes down to the pulse level, may we also assume it would be feasible to display a view of the Cycling Unit oscilloscope, and enjoy watching the pulses traveling through the machine? I believe this would be another first in a low level emulator.

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