Which vintage computers and terminals inspired the various keycap profiles?
I assume IBM was the inspiration behind the OEM profile, and SA certainly looks familiar, but was it from a specific machine, or just meant to be evocative of them? Was XDA from anything in particular?
Even beyond that, I'd just love to hear any trivia about the ties between the history of the industry and the modern hobby.
SA keycaps come from the IBM Selectric I and II typewriters, as well as the Apple II. I think XDA is just a modern profile developed relatively recently, but it is relatively similar to DSA, which I think also goes back decades.
I think you're also right that IBM is behind the OEM profile, which I think was originally used in the Selectric III