[Simh] Unix V7 for PDP11

[Kevin Brunt]

I suspect not.

The DH11 is/was a UNIBUS terminal multiplexer which was around early 
enough to be described in the 1972 PDP11 Peripherals Handbook. I think
one DH11 did 16 lines. From its description in the Handbook, it sounds 
as if a DH11 plus distribution panels plus modem support occupied as 
much volume as a complete QBUS system. The DH11 did DMA on output; the 
Unix V7 clist structure, with 14 characters per queue element, evolved 
to fit in with DH11 DMA.

The DHQ11 (at least as supported by SIMH) is an 8-line QBUS device. 
Whether there is any programming commonality with the DH11, I don't 
know, but I would doubt very much whether the Unix V7 code would run 
unmodified.

Getting multiple DL11 support into SIMH would probably be easier; RT11 
multi-terminal support could use it as well...

Kevin

On Tue, 10 Aug 2004 17:07:57 +0200 (CEST) "[GNC] Andreas Cejna" 
<andreas.cejna at gnc.at> wrote:

> Hi,
> In SIM V3.2-1 support for DHQ11 was added. Is this the module you're
> talking about?
> Regards
> Andreas
> >
> > On Mon, 9 Aug 2004 09:04:24 -1000 (HST) Tim Newsham <newsham at lava.net>
> > wrote:
> >
> >
> >> It's been a few months, but if I remember correctly the extra tty
> >> hardware in simh (dz?) is not supported by v7.  There was a driver
> >> in v7 but it has some comments to the effect that the driver is
> >> not in working order.  I stuck to using the console.
> >
> > This is, of course, a reflection on the DZ11 still being rather
> > new-fangled when Unix V7 was 'issued'. Bell Labs had been using DH11's,
> > so the distribution supported them 'out of the box'.
> >
> > Rather than trying to fix the V7 DZ11 code, it would be easier to add
> > support to SIMH for one of the terminal devices that V7 did support,
> > namely the DH11 and DC11 multiplexers, or what might be easier,
> > multiple DL11 lines, which would just(!) need a 'stretched' version of
> > the console TTY support.

----------------------
Kevin Brunt
Birkbeck College London