how does this delay circuit work? is it just using the fact that signals flow down lines at 1’ per nanosecond, so a 50’ length delays for 50 ns?
-g On Mon, Aug 10, 2020 at 9:40 AM Rodney Radford via TriEmbed < [email protected]> wrote: > This is the first time I have seen another one - thanx for the photo and > the back story. If you find the patent number, I would be interested in > seeing it. > > After watching someone interface an Arduino to core memory at the virtual > computer festival, I wondered how difficult it would be to interface an > Arduino to this delay line. Mine has 12v stamped on the board, so that > gives me some hint as to voltages, and the electronics on the board is > simple, so should be possible to sketch out a schematic of the read and > write circuits. > > > On Mon, Aug 10, 2020 at 3:10 AM Robert Mackie <[email protected]> wrote: > >> Rodney, >> >> Oddly enough, I see the photos attached. >> >> re: a mechanical delay line >> >> My dad worked for IBM way back in the day, as an electrical engineer. >> >> He left me copies of a few of the patents on which he was listed as an >> inventor. One of them is exactly such a device, used at the edge of >> telephone switching networks (I think - edge of some network anyway) to >> hold state. Much cheaper than core memory for the time, and could hold 2048 >> bits, with a latency of something like 50ms. Somewhere I have the paperwork >> for the patent application. Now I'm curious if it was a refinement or the >> first of its type. Never thought about it before. >> >> But this is one where he had kept a physical example, one they had to cut >> open during testing. I knew exactly where it was so I just snapped a photo >> with my phone: >> >> http://mackies.org/mechanical_delay_line_dynamic_memory_ibm.jpg >> >> Figured it would be interesting to see and compare. >> >> Rob. >> >> On Sun, Aug 9, 2020 at 6:14 PM Rodney Radford via TriEmbed < >> [email protected]> wrote: >> >>> Nevermind, the photos 440k were deemed too large to be sent by the >>> TriEmbed server. >>> >>> Sorry you will not be able to see them. >>> >>> >>> On Sun, Aug 9, 2020 at 5:38 PM Rodney Radford <[email protected]> >>> wrote: >>> >>>> I forgot to include the photos... >>>> >>>> >>>> On Sun, Aug 9, 2020 at 5:37 PM Rodney Radford <[email protected]> >>>> wrote: >>>> >>>>> One of the passions I have put time in the last few months are >>>>> collecting and learning about old vintage computers. >>>>> >>>>> I currently have: >>>>> * IMSAI S-100 system >>>>> * Sol-20 S-100 system >>>>> * TRS-80 Model 1 and 4p >>>>> * Two Apple IIe systems >>>>> * Kaypro 10 luggable system >>>>> * TI 99/4 >>>>> >>>>> I used to have a much larger collection including >>>>> * Burroughs L5000 (google about that beast) >>>>> * TRS-80 Model 2, 3 and 4 >>>>> * Zerox CP/M system (I think I still have it, but can't find it) >>>>> * Pet Commodore 2001 (loaned to a 'friend' - never got it back) >>>>> * several Apollo systems >>>>> >>>>> While I wish I could have kept all the old systems, it just was not >>>>> possible due to storage space constraints. >>>>> >>>>> Back in highschool, a teacher gave me her old 4-function Singer (yes, >>>>> the sewing machine) calculator. I, of course, took it apart... ;-) >>>>> >>>>> I did keep two parts from the calculator - the keyboard (mechanica >>>>> marvel) and the storage device (a mechanical delay line). >>>>> >>>>> When I first looked inside, I saw the aluminum box with the words >>>>> read amp and write amp on it, and I *knew* I had found core memory. >>>>> Then I opened it and was completely surprised with what I found. It >>>>> is a magnetostrictive delay line memory device - memory was stored by >>>>> twisting the wire at one end, and the twist would propogate through the >>>>> long coil and out at the other end. By varying the direction of the twist, >>>>> data could be stored temporarily, and it was then sent back in again for >>>>> storage again. >>>>> >>>>> The other item I kept from the calculator was the keyboard. On each >>>>> keypress, the key was decoded with gears and levers that move magnets over >>>>> reed relays - as that was more economical than a simple electronic >>>>> keyboard >>>>> decoder. >>>>> >>>>> >>>>> Here is a link to information about the calculator (and some info on >>>>> the delay line): >>>>> >>>>> >>>>> https://www.oldcalculatormuseum.com/friden1160.html >>>>> <https://www.oldcalculatormuseum.com/friden1160.html?fbclid=IwAR1jtFCm3O_oRCn_hLop43h5fNOtefDedwSv1hVtzH7vUv_TSvCC4qqGjEs> >>>>> >>>>> >>>>> Photos included of the delay line and keyboard. If we were meeting in >>>>> person Monday, I would have brought them out for show and tell. >>>>> >>>>> I also really enjoyed the virtual vintage computer festival I >>>>> mentioned earlier. Some really good talks on that, and my first of four >>>>> books I ordered arrived today - the ENIAC Technical Reference manual, as >>>>> written by one of the first female programmers on it. >>>>> >>>>> >>>>> PS: If you have any old systems that need a home let me know. I really >>>>> should have grabbed the TRS-80 Model 100 that I brought last year that was >>>>> given to the club, but I let someone else take it (any idea who grabbed >>>>> it?) >>>>> >>>>> >>>>> Anyway, back to current time where I need to finish up an IoT device >>>>> for work... ;-) >>>>> >>>>> >>>>> _______________________________________________ >>> Triangle, NC Embedded Computing mailing list >>> >>> To post message: [email protected] >>> List info: >>> http://mail.triembed.org/mailman/listinfo/triembed_triembed.org >>> TriEmbed web site: http://TriEmbed.org >>> To unsubscribe, click link and send a blank message: mailto: >>> [email protected]?subject=unsubscribe >>> >>> _______________________________________________ > Triangle, NC Embedded Computing mailing list > > To post message: [email protected] > List info: http://mail.triembed.org/mailman/listinfo/triembed_triembed.org > TriEmbed web site: http://TriEmbed.org > To unsubscribe, click link and send a blank message: mailto: > [email protected]?subject=unsubscribe > > -- Gregg Tracton: tired, retired & inappropriately unattired (PJ's)
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