[Simh] An idea for graphics support in SIMH

[Michael Kerpan]

On Wed, Jul 7, 2010 at 12:10 PM, Brian Knittel <brian at quarterbyte.com> wrote:
> This seems like a good approach. Besides the PDP-1, the PDP-11 had the
> VT-11 and the IBM 1130 had the 2250. These are very similar devices --
> asynchronous display-list vector display processors. Who knows -- maybe
> someone can rig up an Evans and Sutherland PS2 for the PDP-11/70. (I
> think Tom Ferrin's UNIX V6 drivers are available?).
>
> The approach would also work well for machines with pixel- and
> character-based graphics like the IBM 5100 and 5110. (I have a SIMH
> emulator working, but it's Windows-only at this point due to the
> graphics issue). Then there are the e.g. Cromemco-type boards for the
> Altair, and so on.
>
> It does sort of open a Pandora's Box though, as it invites the
> proliferation of GUI control panels and other fluff. (Says the author
> of a fluffy, hacked-up GUI control panel for SIMH IBM 1130). One thing
> I like about SIMH is that the experience is all about the software,
> rather than on reproducing the physical appearance of the hardware.
>
> The tricky part would be the asynchronous nature of these display
> beasts. Could it be done without using a separate thread? Maybe. Or
> could we work up an abstraction of a display thread that was cross-
> platform and not too ugly? Maybe. It seems to me that this is where the
> difficulty and elegance will lie.
>
> Brian

I kind of figured that the elegance would lie in the fact that all
graphics could be simply written to a "virtual monitor" which would
then be shown to the world by means of RFB/VNC. The outside world
would never talk directly to the display hardware so any asynchronous
aspects could be handled internally. Also, I don't see how emulating
graphical hardware would open the gateway to GUI control panels.
Viewing the output of the virtual Cromemco Dazzler or VT-11 would be
no different in theory than connecting to a virtual serial port over
TELNET is, it's just the remote client program would be one that shows
pictures rather than just text.

Mike