[TUHS] First Unix that could run on a PDP-11 with QBUS

Norman Wilson norman at oclsc.org
Sun Jul 27 15:39:36 AEST 2014

Many Q-bus devices were indeed programmed exactly as if
on a UNIBUS.  This isn't surprising: Digital wanted their
own operating systems to port easily as well.

That won't help make UNIX run on a Pro-350 or Pro-380,
though.  Those systems had standard single-chip PDP-11
CPUs (F11, like that in the 11/23, for the 350; J11,
like that in the 11/73, for the 380), but they didn't
have a Q-bus; they used the CTI (`computing terminal
interconnect'), a bus used only for the Pro-series
systems.  DEC's operating systems wouldn't run on
the Pro either without special hacks.  I think the
P/OS, the standard OS shipped with those systems, was
a hacked-up RSX-11M.  I don't know whether there was
ever an RT-11 for the Pro.  There were UNIX ports but
they weren't just copies of stock V7.

I vaguely remember, from my days at Caltech > 30 years
ago, helping someone get a locally-hacked-up V7
running on an 11/24, the same as an 11/23 except is
has a UNIBUS instead of a Q-bus.  I don't think they
chose the 11/24 over the 11/23 to make it easier to
get UNIX running; probably it had something to do with
specific peripherals they wanted to use.  It was a
long time ago and I didn't keep notebooks back then,
so the details may be unrecoverable.

Norman Wilson
Toronto ON

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