[TriEmbed] Old computers

[Rodney Radford]

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 <rob at mackies.org> 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 <
> triembed at triembed.org> 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 <ncgadgetry at gmail.com>
>> wrote:
>>
>>> I forgot to include the photos...
>>>
>>>
>>> On Sun, Aug 9, 2020 at 5:37 PM Rodney Radford <ncgadgetry at gmail.com>
>>> 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... ;-)
>>>>
>>>>
>>>> _______________________________________________
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