Apollo Core Rope Memory (Apollo Guidance Computer Part 30)

Obligatory shoutout to curiousmarc and Mike Stewart. I’m stunned by the amount of work that have put into making this national treasure (partly) operational again [0] link [1] link [2] ▶ this video

Delay lines are fascinating, but I don't see why this is easier than core memory; seems like you are trading an electronics problem for a mechanical one. Regardless, at the speeds they are targeting, I think delay lines might be difficult. Another interesting option (for ROM) is core rope memory. CuriousMarc has the ultimate explanation: ▶ this video

Here,s a deep, deep dive into AGC rope memory. My mental model was stuck on core memory until I saw this and finally got the difference. Tl;dr Way higher information density. ▶ this video

As seen on Curious Marc, where some real AGC core rope ROMs are read: ▶ this video They even have to work around some design mistakes made in the modules in order to read them correctly. Not many living people know more about the AGC than those guys (especially Mike Stewart).