Well, now my brain cells are gettin' old an' flakey, but here's what I can
still recollect...

I did a port of 4.2BSD shortly after the MVII came out, so we could replace
the 11/780 we had with them (we couldn't afford maintenance on the big beast:-).
(It wasn't that big a job, since the MVII Qbus interface looked just like
 a Unibus adapter. The main trick was the DEQNA and TMSCP. The DEQNA didn't
 do what the doc said and the tape MSCP port wasn't published by DEC. The
 result was a couple of drivers that "kinda worked".) I passed this stuff
along to the BSD crowd (well, actually it wasn't a very big crowd, 4? guys
at the time). Mt Xinu was interested in the port and agreed to help integrate
it into 4.3BSD in return for access to it (or maybe they had written a partial
port too, but needed a driver or something like that). The first release of
the code was in 4.3BSD and actually had DECs drivers for the DEQNA and TMSCP
in it, which worked since they knew how the devices really worked:-)

Sorry, but all those old bits have gone away from my bit bucket. I do have
a 4.3Reno bootable TK50 if nbsdbob wants it. (Be forwarned I have no idea
how you boot the thing. At one point, you had to toggle stuff into the
console to boot the tape and get the old tp monitor going. Basically,
enabling the Qbus interface and setting the base addresses for the Qbus
device registers and base address for the Qbus address map.)

Anyhow, have fun with it, rick
ps: Although I haven't turned it on in years, I still have a MVII sitting
    beside my desk (makes a pretty good foot stool) and am typing this on
    a VT100. (This produces some interesting reactions from the students
    these days, when they try to figure out what kind of computer it is.
    The concept of a terminal that is not a computer is entirely foreign
    to them.:-)