[TriEmbed] Old computers

[Robert Mackie]

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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