Coherent is a clone of the Unix operating system for IBM PC compatibles and other microcomputers, developed and sold by the now-defunct Mark Williams Company (MWC). Historically, the operating system was a proprietary product, but it became open source in 2015, released under a 3-clause BSD License.
https://en.wikipedia.org/wiki/Coherent_(operating_system)
Manpages:
http://www.nesssoftware.com/home/mwc/manpage.php?contents
Manual:
http://www.nesssoftware.com/home/mwc/manual.php
VM: