On 25 June, 07:57, "dennis@home"
wrote:

I had a piece of PROM where you sewed wires through the ferrite rings to
program it.

I doubt that very much indeed.

Ready-laced, and used as RAM (actually NVRAM), yes we've all got the
odd plane or two of that lying around. But PROM by intermittent
lacing? I doubt that very much indeed.

(I'm sure that someone somewhere did make this, I just doubt that
yours used lacing to program it rather than matrix-selected write
pulses.)