XGP - Xerox graphics printer

[larsbrinkhoff]

SYSEN2; XGPDEV - device handler
SYSEN2; XGPSPL - unspooler
SYSDOC; XGP WRITUP
INFO; XGP 24 .INFO.; XGP WRITES

[larsbrinkhoff]

Will accept text files, plot files (vector graphics), or scan files (bitmaps).

[atsampson]

(Relevant for #863 too.)

I've experimented with this a bit on the ats/xgpglp branch. XGP/GLP (XQUEUE) and XGPDEV/GLPDEV work with a bit of tweaking, and XGPSPL at least builds, although none of this is directly useful at the moment.

I was hoping GLP would work with VERSA, but while they use the same spool directory, GLP doesn't produce filenames that VERSA likes...

[larsbrinkhoff]

Maybe se should ask DCP som questions.

• What's the status of VERSA? Should se expert all Venables features to Erik?
• VERSA Verdis GLP filenames.

...anything Else?

[atsampson]

After comparing VERSA 211 and INFO; XGP, there are a number of XGP commands that VERSA either doesn't implement fully (e.g. line spacing, underlining) or doesn't implement at all (margins, vector drawing). I've tried adding support for margins and correct line feed behaviour, which makes TJ6 output look much better.

Do we have any high-quality (ideally 600 DPI) scans of real XGP output? @larsbrinkhoff, you mentioned you had scans of an XGP listing of Dazzle Dart recently... but it would also be nice to have something that uses underlining and multiple font sizes, to compare spacing against.

[36bit]

Do we have any high-quality (ideally 600 DPI) scans of real XGP output?

The book about the Muddle programming language says:

This document was prepared using the PUB system (originally from the Stanford Artificial Intelligence Laboratory) and printed on the Xerox Graphics Printer of the M.I.T. Artificial Intelligence Laboratory.

[eswenson1]

I have real XGP output -- the zork sources printed out from circa 1980. One could scan them in at any resolution. But what good are scans of XGP output?

[larsbrinkhoff]

Right, the Dazzle Dart scan is on the lars/dazzle branch. Maybe it's output from "@"?

Probably many AI memos were printed on the XGP.

I beleve the XGP had a resolution of about 200 DPI.

[larsbrinkhoff]

I removed "SYSEN2; XD 430 - XGP display" because it duplicates #634.

[larsbrinkhoff]

Split off XGP to #1077.

[larsbrinkhoff]

Some pictures of the CMU XGP I got from Clem Cole.

[larsbrinkhoff]

[larsbrinkhoff]

[larsbrinkhoff]

• XGPDEV, XGPSPL, and INFO; XGP 24 added in #926.
• XGP WRITUP, and XGP WRITES added in #1436.

All done.

[larsbrinkhoff]

In 2001, Mark Crispin wrote to ITS-LOVERS:

> 4. There were features of ITS designed to support high quality output.  The
> XGP (Xerox Graphics Printer) was in place by the time I arrived, and I
> believe initial support for ITS was written by Marc Crispin.
                                                 ^^^^ Mark

The program to do font compilation, rendering, and printing on the XGP was
already in place when I arrived.  However, the only way that you chould print
something was link to the mod 35 TTY that had the XGP and give a command to
it.

I wrote the XGP spooler; instead of waiting for the XGP to be free, you just
queued the file to the spooler and waiting for it to print.  To the dismay of
many in the ITS community, it prioritized requests, first by file size and
then by giving AI members (as recorded in INQUIR) a priority boost over others
(LCS, tourists,...).  Rumors to the contrary notwithstanding, I was following
orders from AI management; it was not my decision.  It was about that time
that RMS decided to create his elitist "$" INQUIR classification to indicate
his independence from AI (but "$" also got a priority boost).

It had a few options, including the THESIS option to block printing of the
request until someone gave a command on the XGP mod 35 to indicate that thesis
quality paper was installed in the XGP (at which point requests which didn't
have the THESIS option were blocked until another command was given to say
that ordinary paper was back.

I also wrote a job device called XGP so you could see the status of the queue
and XGP hardware with XGP CTRL/F.

[larsbrinkhoff]

Picture of the SAIL XGP. We can see the customary trash bin.

[larsbrinkhoff]

The SAIL XGP is hiding in the background.

[larsbrinkhoff]

The SSV4 software for the Imlac PDS-4 supports an "XGP graphics mode".

SUBTTL XGP SIMULATOR

[larsbrinkhoff]

From page 62 here: https://www.isi.edu/publications/trpublic/pdfs/sr-75-3.pdf

And page 75.

[larsbrinkhoff]

According to https://www.historyofinformation.com/detail.php?id=970:

by 1972 they were in use at Carnegie-Mellon, Stanford, MIT, Caltech, and the University of Toronto

[larsbrinkhoff]

From https://www.tug.org/interviews/interview-files/morris/morris-render.pdf

[larsbrinkhoff]

The LDX was a fax. The printer side was adapted to make the XGP. Source: http://digitalprinting.blogs.xerox.com/wp-content/uploads/sites/3/2012/08/Xerox-LDX-Image.jpg https://digitalprinting.blogs.xerox.com/2012/08/03/flashback-fridays-looking-back-in-time-at-xerox-history/

[larsbrinkhoff]

An XGP emulator is in development and various bits and pieces to use it is noted here: #2271

[larsbrinkhoff]

Tweets from Geoff Goodfellow:

https://twitter.com/keyboardofGeoff/status/1753083975046922637

you "forgot" the (D)ARPA office at 1600 Wilson Blvd in Arlington, VA & Lincoln Labs in Lexington, MA... IIRC the Lincoln Labs LDXR was connected to the TX-2 and must have been situated before they made an XGP placard cuz it said LDXR

https://twitter.com/keyboardofGeoff/status/1753213478427677174

sorry no, don't have any further information or references you could dig into.. other than yours truly's recollection here... btw, not having an XGP at SRI where SRI-ARC & SRI-AI's computer rooms K2079 abutted one another was A Sore Issue (luckily yours truly had access at SU-AI)

https://twitter.com/keyboardofGeoff/status/1753216297364828306

IRC, at SU-AI/SAIL Les Earnest (yours truly believes) "published" a font catalog called Find A Font (as well as a restaurant guide called YUMYUM) and in Those Days pretty much everything XGP'd was done with/in the "document compiler" PUB markup language that Larry Tesler wrote

[larsbrinkhoff]

A color photo of MIT's XGP. Source: https://www.computerhistory.org/collections/catalog/102803907

[larsbrinkhoff]

Hello @Rick-Shiffman,

Please add your recollections of the ISI XGP to this issue. Thanks!

[Rick-Shiffman]

Hi Lars, I remember looking at the insides of ISI's XGP. It had a one line, page wide, bright green CRT that write one line of the image at a time on a rotating selenium coated drum that's pre-charged. The surface of the drum now has the latent image on it and is sprinkled with toner to develope the image. Now paper is pressed against the drum by a heated roller fixing the image to the moving paper.

also if the XGP's PDP-11 crashed while the XGP was moving paper, then the XGP would dump its large roll of paper on the computer room floor!

Here's Robert Parker's description of the ISI XGP installed in 1974: The Xerox Graphics Printer (XGP) project provided high-quality single sheet document printing capability over a network. In mid-1974, XGP systems were installed at ISI and at ARPA. (ARPA, the Advanced Research Projects Agency, later became DARPA, is a government agency that facilitates technology research).

[larsbrinkhoff]

Thanks Rick!

[larsbrinkhoff]

A better photo from ISI. Source: https://twitter.com/Rrs86595671/status/1754564516669714755