[TriEmbed] Old computers

[Rodney Radford]

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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