Robert is correct - it works by twisting the wire, and has a period of about 3-4 milliseconds.
There is a good description of it here and an engineering drawing of the actuating device: https://www.oldcalculatormuseum.com/friden130.html On Mon, Aug 10, 2020 at 1:09 PM Robert Mackie <[email protected]> wrote: > I don't think it works at nanosecond speeds. More like milliseconds > > The wire is physically twisted by an actuator, and the physical twist > moves down the wire at a predictable rate, like a bend in a jump rope when > you jerk one handle. > > At the other end is a sensor that reads the twist and reapplies it to the > actuator. (Refreshing the values on the medium constantly as the arrive at > the end of the physical wire) This holds memory in the dynamic physical > state of the medium. A read action waits for the right segment of time > (address) to happen and reads out the twist state. A write action waits for > the correct address to arrive and then does NOT repeat the input but > actuates according to the value to be written. > > The unit I showed had an 8 bit register with 8 externalized wires. Send > write, send address, send value. Wait for indication of successful write. > > Send read, send address, wait for indication of successful read, > acknowledge, take 8 bits off interface. Or something very close to that. > > Rob > > On Mon, Aug 10, 2020, 1:00 PM Gregg Tracton <[email protected]> wrote: > >> >> 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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