[jhallenworld]

The 68K had no MMU or even segment registers, so the 68K machines that can run UNIX had, at the very least, some kind of external memory offset adder. I did not know the Apple Lisa had this- it's interesting because Macs didn't have it and could not run UNIX.

[rsecora]

The Motorola 68020 has a MMU coprocessor, and the 68030, 68040 have an on-chip MMU. The Macintosh II, SE/30, Quadra, and Centris series were able to run A/UX [1] since 1988. A/UX was a SystemV with X and Finder.

[1] https://en.wikipedia.org/wiki/A/UX