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* [TUHS] First Unix that could run on a PDP-11 with QBUS
@ 2014-07-27  5:39 Norman Wilson
  2014-07-27  6:02 ` John Cowan
  0 siblings, 1 reply; 18+ messages in thread
From: Norman Wilson @ 2014-07-27  5:39 UTC (permalink / raw)


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



^ permalink raw reply	[flat|nested] 18+ messages in thread
* [TUHS] First Unix that could run on a PDP-11 with QBUS
@ 2014-07-28 13:27 Noel Chiappa
  2014-07-28 22:23 ` Dave Horsfall
  0 siblings, 1 reply; 18+ messages in thread
From: Noel Chiappa @ 2014-07-28 13:27 UTC (permalink / raw)


    > From: Dave Horsfall <dave at horsfall.org>

    > I recall that there were other differences as well, but only minor. In
    > my paper in AUUGN titled "Unix on the LSI-11/23" it will reveal all
    > about porting V6 to the thing.

I did a google for that, but couldn't find it. Is it available anywhere
online? (I'd love to read it.) I seem to recall vaguely that AUUGN stuff were
online, but if so, I'm not sure why the search didn't turn it up.


    > I vaguely remember that the LTC had to be disabled during the boot
    > process, for example, with an external switch.

I think you might be right, which means the simulated 11/23 I tested on
wasn't quite right - but keep reading!

I remember being worried about this when I started doing the V6 11/23 version
a couple of months back, because I remembered the 11/03's didn't have a
programmable clock, just a switch. So I was reading through the 11/23
documentation (I had used 11/23s, but on this point my memory had faded),
trying to see if they too did not have a programmable clock.

As best I can currently make out, the answer is 'yes/no, depending on the
exact model'! E.g. the 11/23-PLUS _does_ seem to have a programmable clock
(see pg. 610 of the 1982 edition of "microcomputers and memories"), but the
base 11/23 _apparently_ does not.

Anyway, the simulated 11/23 (on Ersatz11) does have the LTC (I just checked,
and 'lks' contains '0177546', so it thinks it has one :-).


But this will be easy to code around; if no link clock is found (in main.c),
I'd probably set 'lks' to point somewhere harmless (054, say - I'm using
050/052 to hold the pointer to the CSW, and the software CSW if there isn't a
hardware one). That way I can limit the changes to be in main.c, I won't have
to futz with clock.c too.

	Noel

PS: On at least the 11/40 (and maybe the /45 too), the line clock was an
option! It was a single-height card, IIRC.



^ permalink raw reply	[flat|nested] 18+ messages in thread
* [TUHS] First Unix that could run on a PDP-11 with QBUS
@ 2014-07-27  3:26 Noel Chiappa
  2014-07-27  5:49 ` Dave Horsfall
  0 siblings, 1 reply; 18+ messages in thread
From: Noel Chiappa @ 2014-07-27  3:26 UTC (permalink / raw)


    > From: Mark Longridge <cubexyz at gmail.com>

    > I was digging around trying to figure out which Unixes would run on a
    > PDP-11 with QBUS. It seems that the very early stuff like v5 was
    > strictly UNIBUS and that the first version of Unix that supported QBUS
    > was v7m (please correct me if this is wrong).

That may or may not be true; let me explain. The 11/23 is almost
indistinguishable, in programming terms, from an 11/40. There is only one
very minor difference (which UNIX would care about) that I know of - the
11/23 does not have a hardware switch register.

Yes, UNIBUS devices can't be plugged into a QBUS, and vice versa, _but_ i)
there a programming-compatible QBUS versions of many UNIBUS devices, and ii)
there were UNIBUS-QBUS converters which actually allowed a QBUS processor to
have UNIBUS peripherals.

So I don't know which version of Unix was the first run on an 11/23 - but it
could have been almost any.

It is quite possible to run V6 on an 11/23, provided you make a very small
number of very minor changes, to avoid use of the CSWR. I have done this, and
run V6 on a simulated 11/23 (I have a short note explaining what one needs to
do, if anyone is interested.) Admittedly, this is not the same as running it
on a real 11/23, but I see no resons the latter would not be doable.

I had started in on the work needed to get V6 running on a real 11/23, which
was the (likely) need to load Unix into the machine over a serial line. WKT
has done this for V7:

  http://www.tuhs.org/Archive/PDP-11/Tools/Tapes/Vtserver/

but it needs a little tweaking for V6; I was about to start in on that.


    > I have hopes to eventually run a Unix on real hardware

As do a lot of us... :-)

    > It seems like DEC just didn't make a desktop that could run Bell Labs
    > Unix, e.g. we can't just grab a DEC Pro-350 and stick Unix v7 on it.

I'm not sure about that; I'd have to check into the Pro-350. If it has memory
mapping, it should not be hard.

Also, even if it doesn't have memory mapping, there was a Mini-Unix done for
PDP-11's without memory mapping; I can dig up some URLs if you're interested.
The feeling is, I gather, very similar.

    > it would be nice to eventually run a Unix with all the source code at
    > hand on a real machine.

Having done that 'back in the day', I can assure you that it doesn't feel
that different from the simulated experience (except that the latter are
noticeably faster :-).

In fact, even if/when I do have a real 11, I'll probably still mostly use the
simulator, for a variety of reasons; e.g. the ability to edit source with a
nice modern editor, etc, etc is just too nice to pass up! :-)

	Noel



^ permalink raw reply	[flat|nested] 18+ messages in thread
* [TUHS] First Unix that could run on a PDP-11 with QBUS
@ 2014-07-27  2:37 Mark Longridge
  2014-07-28 15:57 ` Ron Natalie
  0 siblings, 1 reply; 18+ messages in thread
From: Mark Longridge @ 2014-07-27  2:37 UTC (permalink / raw)


Hi folks,

I was digging around trying to figure out which Unixes would run on a
PDP-11 with QBUS.  It seems that the very early stuff like v5 was
strictly UNIBUS and that the first version of Unix that supported QBUS
was v7m (please correct me if this is wrong).

I was thinking that the MicroPDP-11's were all QBUS and that it would
be easier to run a Unix on a MicroPDP because they are the most
compact. So I figured I would try to obtain a Unix v7m distribution
tape image. I see the Jean Huens files on tuhs but I'm not sure what
to do with them.

I have hopes to eventually run a Unix on real hardware but for now I'm
going to stick with simh. It seems like DEC just didn't make a desktop
that could run Bell Labs Unix, e.g. we can't just grab a DEC Pro-350
and stick Unix v7 on it. Naturally I'll still have fun checking out
Unix v5 on the emulator but it would be nice to eventually run a Unix
with all the source code at hand on a real machine.

Mark



^ permalink raw reply	[flat|nested] 18+ messages in thread

end of thread, other threads:[~2014-07-29 14:33 UTC | newest]

Thread overview: 18+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2014-07-27  5:39 [TUHS] First Unix that could run on a PDP-11 with QBUS Norman Wilson
2014-07-27  6:02 ` John Cowan
2014-07-27 14:10   ` Bill Pechter
2014-07-27 17:16     ` Dave Horsfall
  -- strict thread matches above, loose matches on Subject: below --
2014-07-28 13:27 Noel Chiappa
2014-07-28 22:23 ` Dave Horsfall
2014-07-29  9:46   ` Warren Toomey
2014-07-29  9:56   ` Dave Horsfall
2014-07-29 14:33     ` Clem Cole
2014-07-29 13:10   ` Milo Velimirović
2014-07-27  3:26 Noel Chiappa
2014-07-27  5:49 ` Dave Horsfall
2014-07-28 22:04   ` Warren Toomey
2014-07-28 22:38     ` Warner Losh
2014-07-29  9:06       ` SPC
2014-07-29 13:28     ` Clem Cole
2014-07-27  2:37 Mark Longridge
2014-07-28 15:57 ` Ron Natalie

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