[TUHS] Can PDP-11/23 PLUS run Unix?

[Clem Cole via TUHS]

Absolutely.  v7m was the precursor to both Ultrix-11 and 2.9BSD [2.10BSD
took from Ultrix-11, while 2.8 and 2.9, v7m]. You can even see the emails
from DEC giving the Berkeley team to use anything from either

I suggested Ultrix-11 as I know it has simple (binary) installation media
readily available that supports the 11/23 [sources are also on TUHS].  But
unlike V7m, it was a standard product (supported by DEC at the time)
packaged appropriately  and included a number of enhancements (ie it was a
DEC product and you can even download a PDF of it’s official software
product description (SPD) - which is the official document that described
what DEC would provide support.


v7m was basically a tape distribution by DEC made available to Unix V7
licensees ( and followed the ATT “abandoned on your doorstep” style of
license).  But yes, it supports more models of PDP-11 than the original
Seventh Edition but trying to get it running on real hardware will take
more effort.


Sent from a handheld expect more typos than usual


On Thu, Feb 26, 2026 at 6:06 PM Madeline Autumn-Rose <b4 at gewt.net> wrote:

> v7m is also an option
> Sent from my iPhone
>
> > On Feb 26, 2026, at 15:03, Clem Cole via TUHS <tuhs at tuhs.org> wrote:
> >
> > 
> https://gunkies.org/wiki/PDP-11/23#:~:text=hampage.hu,are%20no%20problems%20with%20this
> .
> >
> >
> > To your questions. Because it lacks separate I/D
> > Space and does not support supervisor mode (only user and kernel) 2.11BSD
> > will not work.  However V6 and V7 are possible. I think Ultrix-11 should
> be
> > able to work and is more likely to have the low level details that 11/23
> > will need.
> >
> >
> > Sent from a handheld expect more typos than usual
> >
> >
> >> On Thu, Feb 26, 2026 at 5:52 PM ROBERT MYERS via TUHS <tuhs at tuhs.org>
> wrote:
> >>
> >> I’ve just obtained a 11/23 Plus system off of EBay and plan to get a
> QBone
> >> to emulate memory along with a few other things.  I need to know if
> >> Floating Point support is a requirement as well if I can also emulate
> up to
> >> 4 Mb of memory.  I’m interested in v6/v7/BSD2.11 for Unix variants.
> >> Sent from my iPhone
> >>
>
>