I did a port of a word processor to QNX 25 years ago, so that makes it old as the hills and the system calls must have been Unix compliant. Other than that I d

I did a port of a word processor to QNX 25 years ago, so that makes it old as the hills and the system calls must have been Unix compliant. Other than that I dont remember much. Plan 9 is of similar vintage. Even Linux is newer.