On Tue, May 10, 2022 at 1:35 PM Richard Salz <rich.salz@gmail.com> wrote:

> Per wikipedia (FWIW), V7M was for PDP-11; Ultrix was the first VAX unix
> project and based on 4.2BSD.  https://en.wikipedia.org/wiki/Ultrix
>

At some point, Unix V7M was rebranded as Ultrix-11 and pulled in a lot from
the BSD releases (2.9 or 2.10) to get TCP/IP
networking onto the PDP-11. I don't think DEC ever shipped pure AT&T
binaries. The V7M was a modified version of V7,
with most of the modifications in the kernel to fix a few bugs with buffer
handling, and also make it run on all the different
PDP-11 models.

All the sources to V7, V7M and the last Ultrix-11 version are in TUHS for
people to peruse...

Warner