From: jnc@mercury.lcs.mit.edu (Noel Chiappa)
Subject: [TUHS] First Unix that could run on a PDP-11 with QBUS
Date: Sat, 26 Jul 2014 23:26:39 -0400 (EDT) [thread overview]
Message-ID: <20140727032639.46B6718C0DE@mercury.lcs.mit.edu> (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
next reply other threads:[~2014-07-27 3:26 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-27 3:26 Noel Chiappa [this message]
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
-- 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 5:39 Norman Wilson
2014-07-27 6:02 ` John Cowan
2014-07-27 14:10 ` Bill Pechter
2014-07-27 17:16 ` Dave Horsfall
2014-07-27 2:37 Mark Longridge
2014-07-28 15:57 ` Ron Natalie
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20140727032639.46B6718C0DE@mercury.lcs.mit.edu \
--to=jnc@mercury.lcs.mit.edu \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).