Most of the software on the AGC (Apollo Guidance Computer) is stored in a special read-only memory known as core rope memory, fashioned by weaving wires through and around magnetic cores, though a small amount of read/write core memory is available.
Bonus Nerd Link: the Virtual AGC Project
Hey there. If you find this fascinating, theres a youtube channel that is trying to restore said computer and goes over how it works in detail: https://youtu.be/hckwxq8rnr0?feature=shared
That video was how I learned about it!
I highly encourage anyone even slightly interested in how a rope core computer works to watch that video. The whole series is fantastic too.
Thank you for finding that, Todotoro. I meant to but completely forgot to do it.