EEVblog 1713 - CRAZY Density Magnetic Core Memory!
Added 2025-10-05 00:28:05 +0000 UTCPre-release.
Found this in the bunker! Don't remember where I got it from, but it's cool.
Comments
Core read is destructive, but almost every core will read the bit, then immediately, in the same machine cycle in the core controller, write it back. thus in core memory you had lots of power monitoring, to lock the core itself from being read when the power is busy shutting off, so that any read or write in process will complete before the voltages drop too low, thus they will deselct themselves on power fail being asserted, after completing the current operation, though a lot of the later CPU had a non maskable interrupt that got the power fail 1ms before the core got it, and this allowed enough time to store the on CPU registers, like stack pointers and other on CPU registers in a special section of memory, so that a shutdown would not result in corrupted data in the core for the next power up.
Sean Beukes
2025-10-06 13:41:11 +0000 UTCAfter watching the video, excellent as always Dave, I remembered when I worked for Cray (which is still the fastest general purpose computer and is at Oak Ridge Labs in Tennessee), that the scientists I was talking to said the fastest “non general purpose “ are still analog, using op amps. He said they have projects that require trillions of integrations/differentials per second and that GP computers can’t even come close in speed. I can only imagine what you’re doing that requires trillions per second. These are of course specialized machines. He gave me one more hint, real time processing was required.
Billy Martin
2025-10-06 07:50:21 +0000 UTCOne of the amazing things about core memory, if my own core serves me properly, is that reads were destructive. One other thing, when I worked for a 3 letter government agency in the 80s they said they still used them due to being immune to EMP pulses. Not sure how true that was but it was a cool story.
Billy Martin
2025-10-06 07:16:10 +0000 UTC
