Graphics extension

[larsbrinkhoff]

See RFC 746, The SUPDUP Graphics Extension.

[larsbrinkhoff]

I'm not sure if there are any applications that use this? The RFC is written by RMS, so I'm assuming it was done with ITS in mind.

@dabridgham, what do you think?

[larsbrinkhoff]

The protocol allows for both vector and bitmap displays.

[dabridgham]

I always wondered what graphical programs ran on ITS that used this extension. SUDS maybe? Or could someone port SpaceWar to it? I never paid much attention to the Graphics Extension as I didn't know of any use for it. Now the Local Editing Protocol, that interested me, though I never got around to implementing it either. I wanted to put it in the Unix SUPDUP server for line editing.

[larsbrinkhoff]

Thanks. It's no use if there are no applications.

[larsbrinkhoff]

@ams, the Lisp Machines used SUPDUP, right? Would the applications use the graphics extension?

[dabridgham]

Ask RMS, maybe?

[larsbrinkhoff]

He was rather brusque that one time I for TECO advice. But yes, I'll do that.

[larsbrinkhoff]

Found an app: PDP-10/its#635

[larsbrinkhoff]

Also some Lisp code by David C Plummer. Is he around?

[larsbrinkhoff]

RMS has forgotten all about the graphics extension. He didn't even remember the RFC and section in AIM-644 he wrote.

[ams]

I will check the Lisp Machine System code and see if it was ever implemented there. But I am not aware of any system that used the graphic extensions.

[larsbrinkhoff]

Thanks. Keep an eye out for DCP code.

[larsbrinkhoff]

New information from DCP:

There were two terminals that supported SUPDUP graphics: the (John) Kulp terminals in the Plasma Fusion Group in Building 38, and later terminals designed by Chuck Linton down at the Plasma Fusion Center down Vassar Street. Those terminals were driven by a little OS I wrote called MINITS (Mini-ITS was the intent). So if you can find a MINITS directory, you’ll find a whole bunch of PDP-11 PALX code, and in there someplace are the display drivers that are the receiving/display end of the protocol. (I’m told the network bridge and terminal concentrator features of MINITS were popular enough they ported the PALX compiler to some kind of VAX system. So there may have been further development over there, but probably not for display terminals.)

[larsbrinkhoff]

Another application: The Versatec/Gould printer spooler can display files using SUPDUP graphics.

CC @atsampson

[larsbrinkhoff]

Maybe use the Tektronix emulator built into xterm?

[ams]

The Lisp Machine system has graphics support for SUPDUP, at least since System 78; see SYS: WINDOW; SUPDUP LISP.

[larsbrinkhoff]

I think maybe graphics is better added to PuTTY (once SUPDUP support is merged), than this repository which is decidedly text oriented.