[Simh] GPX Graphics for VAX

[Andrew Balaam]

I have used the SIMH emulation system on and off for quite a while, and 
find it a fine VAX emulator. I appreciate that SIMH is a general purpose 
emulation package rather than purely a VAX emulator - but VAX is my prime 
interest.

I have a number of old CAD packages that I still run on real VAXen 
(3100/76s) and (4000/90). I would really like to run this stuff on an 
emulator. As the speed of modern computers improves, so the emulation 
speeds improve - If I remember correctly, SIMH running on an AMD XP2800 
under Linux is faster than a 3100/76.

I believe I am correct in saying that:-
1.	The fastest VAXstation that supports a GPX graphics card is the 
3100/76
2.	VWS never supported (officially or unofficially) an SPX graphics card.

The software I have requires VWS.

I know that DEC produced a migration package that allowed VWS software to 
run on top of X (i.e. DECwindows). I have used this, and it does work, 
though it is not the most reliable nor convenient piece of software.

I suppose, What I am working up to asking is; what are the chances of 
implementing an emulation of the GPX graphics adapter and the keyboard 
and mouse devices for the SIMH VAX emulator?

It is a job I would be prepared to look at, though I have absolutely no 
documentation on the GPX, keyboard or mouse hardware, and have (at the 
moment) no idea how to add things to SIMH, nor a very good understanding 
of the VAX I/O subsystem etc...

I also appreciate that SIMH is currently platform independent - and 
adding such a peripheral would probably be difficult (if not impossible) 
to do and preserve the platform independence (Unix uses X, Windows 
doesn't etc...), though if I had the necessary information I would be 
happy to produce/use an X window only version.

Off-topic...
If anybody is interested, I am writing an emulator for an old English 
computer called Susie - http://www.geocities.com/susievem/SusieV.html

Andrew.