My undergrad CS degree I don't think contained any sort of OS course, other than maybe a survey of them but there was a graduate level class that was required f

My undergrad CS degree I don't think contained any sort of OS course, other than maybe a survey of them but there was a graduate level class that was required for any higher degree. I took it before I graduated with an undergrad because it was interesting, and it was quite extensive as I recall. That was well over 20 years ago, however.