[Simh] Graphics Terminals and Graphic System Phototypesetters

[Paul Koning]

> On Dec 9, 2015, at 10:33 PM, Will Senn <will.senn at gmail.com> wrote:
> ...
> Is is possible to simulate a graphics terminal in SimH for the PDP-11/40/45/70. So far, I have been able to get a text console working (I think it's a Teletype ASR-33) and serial consoles (DCI). I have seen some video of real PDP's playing lunar lander and such on graphics terminals, and if this is possible in a simulated environment, I would like to try it out.

There are two parts to this.  One is the conversion of the output data stream to the image.  The other is the interface used.  In the case of a GT40, you have a distinct interface along with its encoding of graphics.  If you have something like that but with a different interface, you'd have to emulate that interface.  (For example, if you wanted to emulate a VT20, that's what would be involved.)

On the other hand, if you're dealing with a graphics terminal that interfaces via a serial line, the existing serial port interfaces would work and "all" you need is an external program that connects to that data stream -- say, via a telnet connection -- and turns it into a graphics image.

> Also, is it possible to simulate a graphics system phototypesetter? I get the feeling that this is what TROFF was actually designed for and would be interested in trying it out, as well.

Same issue, basically.  The typesetters I remember from my days in Typeset-11 used a parallel interface somewhat like a line printer interface but, I think, not exactly the same.  Emulating that would be quite easy.  The data stream was proprietary to each typesetter, so the main task would be to interpret that data stream and translate it to graphics primitive for your chosen modern output device.  For example, it would probably be fairly straightforward to map old style typesetter output into PostScript.  The biggest issue might be finding adequate typesetter documentation, though for the Unix case you can, if all else fails, reverse engineer the application software that was used to drive it.

	paul