Other PDP11 simulators

From: Doc Shipley <doc_at_mdrconsult.com>
Date: Sat Oct 2 12:39:34 2004

Ron Hudson wrote:

>
> On Oct 1, 2004, at 11:15 PM, Tom Jennings wrote:
>
>>>> Are there any PDP11 simulators that run "right down on the iron" of
>>>> a PC?
>>
>>
>>> What do you mean "right down on the iron"? You couldn't run PDP-11
>>> binaries
>>> on i386 hardware, if that's what you mean. Do you mean something
>>> that is
>>> effectively a self-contained operating system, that will boot up and
>>> just be a
>>> PDP-11 emulator?
>>
>>
>> An x86 runs x86 code, an '11 runs '11 code. To make the twain
>> meet you need a simulator or an AWFUL LOT of transistors. What's
>> wrong with one of the OS-loaded simulators?
>>
>>
>
> Well, two things... I would like the simulator to be able to use the
> serial ports, and perhaps a
> serial service board and the parallel port for a printer.
>
> Also I would like the simulator to become available without user
> intervention (though I suppose I would still have to enter the
> 3 ^j s for RSTS to come up.

   What distribution of Linux are you running? Everything you want to
do could be done by manipulation of the startup scripts on most Linux
systems. I wouldn't go so far as calling it "trivial", but it won't be
complicated at all.

   If I were going to design a drop-in install to do this I'd probably
use Debian or Slackware, but whatever you're using should do fine.

> Right now I login to my linux box as root, cd to the /opt/simh directory,
> run screen (so I can detach from the simulator once I get RSTS going)
> run simh with a startup file, type what I need to to bring RSTS up, then
> detach.

   All this can be done either in root's startup scripts, so that it's
automagic when you log in, or as root in the system scripts, so that
root can attach to the sessions after login.

> What do you have to do with a real PDP-11 to get to
> the point where RSTS is running and people can login?

   I don't run RSTS, so I don't know.

> In my ideal simulator, The screen and keyboard (and mouse) would be the
> operator console and
> keyboard/screen of KB0: (put the vga monitor into 50x80 and use the top
> half for the op console
> and the bottom 24x80 for vt100 (hazeltine?) emulation. (or even
> decwriter of some sort emulation where
> the lines off the screen are buffered and can be scrolled back to or
> dumped to the printer)
>
> If I wanted to make things more simple, I could have the 80x25 screen
> switch between KB0: and op console.

   The simplest solution here would be to run X with a very simple
window manager, and autostart tiled xterms that attach to the running
simh session. I _think_, but would have to look it up, that if you want
them both visible you need not to run screen, or run two screen sessios
if you need to detach.

   If you'd rather do text mode than X, why not use Linux's virtual
consoles instead of screen?

> I suppose a third mode would let me attach and detach files to simulated
> devices without stopping the
> simulation.
>
> I suppose I ask too much.. :^)

   Probably. ;)

   I don't have a lot of spare time right now, but if you'd like to
pursue this as a project tag me off-list. If it works the way you want,
we can document it and post it back here for comment and improvement.


        Doc
Received on Sat Oct 02 2004 - 12:39:34 BST