I may have mentioned before, I’m kind of old. One measure of how old I am is the fact that I’ve actually programmed machines that used core memory. Real core memory. Little ferrite donuts on arrays of wires.
Some time ago, I remember running across this awesome blog post from “Wayne’s Tinkering Page” which showed some experimentation in creating a driver for some surplus 1mm ferrite memory cores, effectively creating a single bit memory. I thought that was pretty darned cool. But what’s even more amazing is what Ben North and Oliver Nash have done: create a 32 bit core memory shield for an Arduino.
Links to the report and board plans, bill of materials and software
And they have an excellent report on the project, which includes a reference to a different core memory technique which employed non-destructive reads.
Very cool.
I’m kind of old too! old enough to have started programming on a KIM-1 in the late 70s and just old enough to have worked on a machine with core memory. My high school computer for my first year (1979 or 1980) of high school computer science was a PDP – 8/A also known as a CLASSoom Interactive Computer (CLASSIC) and I remember our physics teacher pull out an 8 or 16 K core stack to show me. The next year we switched to an Apple ][+ lab.