I’ve always thought POSIX compliance is the primary thing vendors should be targeting for portability. I was trying to find something that would explain the dif

I’ve always thought POSIX compliance is the primary thing vendors should be targeting for portability. I was trying to find something that would explain the difference between POSIX and UNIX compliance, but there’s not great sources on this specifically. I imagine UNIX is a superset of POSIX, I’d be curious if anyone knows of a simple comparison between the two?