Plane of core memory

[Jim Manley]

Jussi Kilpelainen's page cited above (
https://www.tindie.com/products/kilpelaj/core-memory-shield-for-arduino/)
refers to the work of Ben North and Oliver Nash to create another core
memory shield for Arduino Unos.  Their site inspired Jussi to create his
shield kit, which can be viewed at:

http://www.corememoryshield.com
<http://www.corememoryshield.com/report.html>


Ben's and Oliver's home page contains a link to the files:

http://www.corememoryshield.com/Core-Memory-Shield.zip

It also contains a link to a page with the detailed explanations and
schematics for core memory circuitry needed to read and write to core:

http://www.corememoryshield.com/report.html


Wayne Holder shows how to build the most minimal circuit using an SN754410
driver IC (http://focus.ti.com/docs/prod/folders/print/sn754410.html, about
$2.50 each for one, and a bit over $2.00 each for 10) and an Arduino Nano
(about $5.00 each for one, and around $3.50 each for 10) to address one bit
of core memory and, more importantly, how to expand the circuit to address
larger numbers of bits/cores using more SN754410s:

https://sites.google.com/site/wayneholder/one-bit-ferrite-core-memory

There's enough information on Wayne's page to build the circuitry to access
any arbitrary number of cores, with the number of cores/bits being
addressable increasing by a factor of four for each doubling of the number
of driver ICs.  ePrey has lots of old core memory planes available for as
little as $30 each for about 500 bits, with intact wiring (from Russia or
the Ukraine, which developed much of the Soviet Union's weapons systems and
advanced commercial electronics).  So, you can just wire the above circuits
to their pins instead of going through the hate and discontent of testing a
ziplock bag of 500 ~2,000 teensy-weensy cores (from Bulgaria) to find
enough with the right properties, and then having to weave your own plane.

All the Best and Enjoy!
Jim