Posted by cainxinth 2 days ago
That's a neat idea. I can see how it would work. A PERT chart is a time-oriented acyclic dependency graph. Each task has a duration, and tasks can be in parallel. At join points in the graph, the later end time determines the time value for the end node, and that feeds the following tasks.
So an analog computer could do this with voltage=time and resistance=duration. The picture shows a compact plugboard at the lower right. That's the dependency graph. Then there are lots of knobs, for setting task duration. For each join point, there would be a circuit to pass through the higher voltage (maybe just diodes, although diode drop would be a problem; might need an op amp). Then you have lights to tell you which path is longer at each join point. Now you can tweak the knobs and adjust the schedule. There ought to be a meter available for reading out times, but maybe that's external.
It was this connection that ultimately blocked Eckert and Mauchly from patenting the idea of the digital computer.[1]
[0] https://en.wikipedia.org/wiki/John_Vincent_Atanasoff [1] https://en.wikipedia.org/wiki/John_Vincent_Atanasoff#Patent_...
From Wikipedia:
>The UNIVAC was manufactured at Remington Rand's former Eckert-Mauchly Division plant on W Allegheny Avenue in Philadelphia, Pennsylvania.[1][9] Remington Rand also had an engineering research lab in Norwalk, Connecticut, and later bought Engineering Research Associates (ERA) in St. Paul, Minnesota. In 1953 or 1954 Remington Rand merged their Norwalk tabulating machine division, the ERA "scientific" computer division, and the UNIVAC "business" computer division into a single division under the UNIVAC name.
I'm guessing all the coolest stuff had long since happened before my relative was there.
> Definitely not yet on the market, but envisioned by Dr. John W. Mauchly, is a miniature computer for household use that will not only make shopping lists obsolete but will also mark the extinction of the grocery clerk and the checkout-counter man. Before going to market, a woman will slip her computer into her purse (it will have an inventory of what she needs in the way of staples and supplies stored in its wafer-thin memory cells). Once at the market, she will plug her computer into a socket in a vacant “delivery alcove” and wait for the results. The computer will carry out the business of identifying itself, making the proper accounting entries in its own memory, and authorizing the charge against its mistress’ universal checking account. In less than a minute the order slides down a chute, and the housewife brings home the electronic bacon. Dr. Mauchly, who invented some of the original big computers and has already built one the size of a suitcase, is working on the pocket monster.
[0] https://time.com/archive/6625605/the-marketplace-build-small...
https://en.wikipedia.org/wiki/File:Women_holding_parts_of_th...
(This is a repost of an older comment I made)