Talk:Fabritek Core Memory

Still here?

I'm somewhat amazed the one from AI still exists. I would have assumed it would have been junked when HIC did the work to enable LISPM memory to be used on AI to replace the failing core memory. (I forget what hardware was used for the second moby on AI.) Jnc (talk) 21:22, 5 July 2019 (CEST)

I'm amazed too! I had the idea that they should scan the contents, but I suppose the bits have dissapated by now. I think the other moby was an Ampex... but the final configuration had three mobies. The fourth was dedicated to the 10-11 interface and PDP-6. Larsbrinkhoff (talk) 07:27, 6 July 2019 (CEST)

Generally core maintains its contents for a very long time; I've read of other old core memory being read out decades after last use. But in this case I doubt it would be worth it; the contents would either be i) stuff we have already (ITS system/commands), or ii) junk of no interest (personal data).

AI's pager had a hardware address space of 4 mobies, but I'm pretty sure only 2 mobies of actual memory. I think the third was the PDP-6 main memory; the 11's had a moby to themselves. (IIRC, they didn't tweak the memory bus cables, the way they did with the I/O bus; the pagers (on all 3 machines) just had 2 or 4 totally stock memory bus cables coming out of them, which were cabled to the appropriate boxes.) Jnc (talk) 15:48, 6 July 2019 (CEST)

Some time ago I made notes about how the memory sizes of the ITS machines evolved: https://github.com/PDP-10/its/issues/1585

According to this, AI was as you describe at one point. But later a third moby was installed, and the PDP-6 and 10-11 was made to share a moby. ITS has code to accommodate this configuration. Larsbrinkhoff (talk) 18:47, 6 July 2019 (CEST)