hckrnws

hckrnws

RAM: the forgotten history (2024)

(blog.coredump.cx)

118

6

3d

by Luc

myself248
51d
An unsung benefit of core memory's non-volatility is that, decades later, forgotten core stacks discovered in storage might still retain whatever data they held when they were powered off.
You just only get one chance to read it.
I'm not aware of any good writeups of such discoveries, though.
1. mkj
  01d
  Could you read it with a flatbed scanner or other photography? That should be unobtrusive.
2. ganzsz
  31d
  This is also true for spinning rust, e.g., magnetic drum memory.
  1. kjs3
    21d
    Sometimes. Coatings on drums and platters are subject to flaking off and other deterioration, particularly if they weren't stored in completely perfect conditions. Tiny bits of coating cause head crashes which destroy much bigger parts of the surface. Also, over time, the backer for the rust can deform, which also leads to head crashes. Core memories are fragile in their own way (tiny, brittle wires...), but my gut is they're a bit more resilient that iron oxide coating.

jandrese
11d
Usagi Electric managed to recover the code from a 1960s era LGP-21.
https://www.youtube.com/watch?v=IBjh0SaA5dc
https://www.youtube.com/watch?v=39SwIl3wQDw
The coating wasn't a problem, it was a couple of the heads that sort of failed.
1. kjs3
  01d
  Yeah, I saw that via another forum. You should check out his G-15 restore; it's epic. That LGP-21 looks almost pristine, and based on the back story, they guy who originally had it sounds like the kind of guy who knows how to store vintage kit. That thing didn't come out of a barn someplace, so not surprising the coatings survived. :-)