Core Memory

Several of the first computers I used had core memory for RAM. Core was reliable, and one plus is that it retained its contents when power was removed. Some computers took advantage of this and, upon bootup, could save the contents to disk.

I have a couple of core boards, one from a PDP-10 and one from a PDP-11. I haven’t seen since I last moved a few years ago; I’m sure they are in a box someplace.

Here are some images of core memory.

4K Memory Card

Here is a close-up view of a core board – you can see the individual bits:

Close-up view of core memory

And here is what one bit looks like – not all that small.

Early core memory boards were wired by hand. Makes my eyes hurt thinking about that.