Salute to old-tech!

First of all, does anyone have any specific information on Magnetic Core Memory? (Magnetic-core memory - Wikipedia)

I've got the basics of "Core Memory" operation down, but can't find any good, detailed (but understandable) information on how to practically implement it. Shouldn't really be that hard.. use transistors to control x/y lines through a single ring core, and use an analog input with a low aref to detect the slight voltage spike as the core's magnetic field flips.

Second, is it possible to build an "optical latch" using a LED, an LDR and some other components? This might be a stupid question, and I have no real use for a solution apart from learning. What I mean is: a LED, once turned on, shines on an LDR causing it's resistance to drop, providing enough voltage for the LED to keep it's light on (and the LDR's resistance low).

Thanks for reading my rather random rant! ::slight_smile:

is it possible to build an "optical latch" using a LED, an LDR

Yes many many years ago I had a Phillips electronics kit (possibly 1964). With that I made a relay with a LDR in series with the coil. The relay contacts were used to light a torch (flashlight) bulb. Depending on if I used the normally open or normally closed contacts I got a latch, or a relaxation oscillator.

Sorry I have never used magnetic core memory, although I once saw one in a surplus shop in Manchester, again in the 60's.

I believe there are a bunch of obsolete equipment fans around. Maybe google around one of the online museums. If you don't come up with anything pm me. i know someone who could probably tell you how to build a single core from scrtatch.

optical latch using optoisolators: http://www.edn.com/article/CA220403.html