As a kid back in the 60s I noticed that I heard this word a lot in southeast Asia, Europe, Australia and the USA. I think I noticed it because I read in a few books that it was used a lot.

And I suppose there were computers in the 1960s, but I doubt it had anything to do with it. ISTR the "explanation" (conjecture) was US culture, GIs all over the place, and WWII. But I also remember reading that it came from west Africa, though that is not contradictory with the spread-by-US-ubiquity theory.

Ok was popular way before computers became a thing, as I grew up in a small Asian village before either computers or cellphones were a thing. Maybe it's the other way around. Ok is so used in computers because it is familiar to everyone