Z80 mode to run cpm

8080 mode, not Z80. Did run CP/M, and I used 22nice for probably longer than needed. Unfortunately over time lots of cool software assumed a Z80, sooo...

Xenix was just pollute and delute - system V with some BSD thrown in

Which Xenix? It was originally V7 based, and 'upgraded' to System III around version 3. I forget what it looked like between version 3 and version 5.x, where it became System V based (+ stuff).