SCHMIDT@SUMEX-AIM.STANFORD.EDU.UUCP (04/11/87)
Since there are few people who have actually seen an Interpress and/or DDL
printer, it's hard for anyone to say anything that isn't based on some
manufacturer's claim or second-hand knowledge.
I think Interpress printers have been on the market since 1982.
We got our Xerox 8046 in January, 1985.
[...] Xerox says that Interpress is designed for speed and is faster than
PostScript. Considering that the only version of Interpress that's
available now doesn't do graphics, only text and scanned images (no
vector graphics, clipping, or rotation of text), I can see why it's fast.
Ours does vector graphics, clipping, rotation of text, and a few other
things. It does have a few weaknesses. Text can be rotated only in
the case that the printer possesses pre-rotated font files. (But how
often do you use fonts at rotations other than 90 degrees?) It doesn't
do arbitrary curves. Our Xerox workstation software computes the
arbitrary curves and uses line graphics to render them...a kludge, but
users don't care where the math is done. (We use Interpress 2; not 3.)
I wouldn't say that the 8046 is a fast printer.
For speed we (Stanford Knowledge Systems Lab) use 7 Imagen laser
printers, all on ethernet. All of them (8/300, 12/300, 3320) generally
operate at the rated speed of the print engines (8, 12, and 20 ppm).
Re: DDL--
I think DDL was invented mainly in the hope of chilling postscript.
Back when the LaserWriter was the only PS machine on the market and
Imagen was touting the 3320 and DDL, we decided to give PS a miss and
buy the 3320 since the speed of the Apple was too low and, well, DDL
was going to be even better than PS, right? As it turns out, DDL is
not available on the 3320. (I re-read my junk mail, and, sure enough,
Imagen never actually promised that DDL would run on any of their extant
laser printers; just that it was a better PDL than PS.) I called
Imagen when the 3320 arrived and they said that they had no plans
ever to support DDL on the IP/II series of printers.
A back-of-the-envelope calculation indicated that the Impress page
description language (supported on all Imagen IP/II products) is
adequate for 99.6% of the half million pages we print each year, so
I still believe we went with the right product, if not my favorite
PDL (which is, in fact Postscript). To accomodate the 0.4% of the
print jobs that require PS, we bought a LaserWriter and that, in turn,
encouraged some people to switch from other drawing tools to MacDraw,
and now 0.8% of our print jobs go out in PS. The overwhelming majority
of our users (probably more impatient than the average, since many
were weaned on 60 ppm Xerox dovers) prefer speed to the potential
of arbitrarily transformed fonts, etc..
I sure wish Imagen would offer a Postscript emulator for the IP/II
series of printers. Then (I think) we'd have the best of all worlds.
--Christopher Schmidt
-------phil@RICE.EDU.UUCP (04/13/87)
>From: gymble!harvard!topaz!unirot!patwood@brillig.umd.edu (Patrick Wood) > Since there are few people who have actually seen an Interpress and/or DDL > printer, it's hard for anyone to say anything that isn't based on some > manufacturer's claim or second-hand knowledge. Now let's hear from someone who not only has seen an Interpress printer, but worked on one during the summer of '84 writing Unix ditroff support software for it ......... me! > Xerox says that Interpress is designed for speed and is faster than > PostScript. Considering that the only version of Interpress that's > available now doesn't do graphics, only text and scanned images (no > vector graphics, clipping, or rotation of text), I can see why it's fast. Interpress IS designed for speed. Interpress files are 8 bit data and NOT ASCII. An Interpress command is one byte long instead of a space-terminated string of arbitrary length. This means faster interpretation on the printer server end and faster transfer time since Interpress files are smaller than, say, Postscript files. Now, it's been awhile, but I definitely remember line graphics and I definitely remember that that 8044 I used did them. I also remember, however, that it did not do circles and arcs and splines (I had to build bitmaps and ship those to do the equivalent ditroff graphics). But I'm almost positive that it did line graphics. What else would you mean by "vector graphics"? And it certainly does rotation of text. However, unlike Postscript, the standard Interpress server needs to store the fonts pre-rotated. So (although the standard does not make this restriction) no Interpress printers are capable of *arbitrary* rotation of text: they are capable of certain transformations. Adding more fonts gets more rotations. Clipping I never tried, so I can't say anything about that. > Read that any way you want, to me it means that > Interpress gains speed by giving up some flexibility. But not much flexibility. They gave up the ability for actions on one page to influence actions on another (nothing from one page carries over). It is not clear to me that such a "feature" is all that advantageous. The first part of every Interpress file is a "preamble". The state of the printer at the end of the preamble is used as the starting state for every page in the document. So, fonts and transformations and other global stuff is defined in the preamble and is then available at the beginning of every page. But one page can't do something (either intentionally or inadvertently) that affects pages later in the document. This make it MUCH easier to arbitrarily rearrange pages to your heart's content. I understand that this approach is *possible* in Postscript, but not *enforced*. This makes writing a program to rearrange any given Postscript file much harder. Right? William LeFebvre Department of Computer Science Rice University <phil@Rice.edu>
root@phw5.UUCP (04/15/87)
We could debate the issue of which PDL is "better", "faster", "more flexible", etc., and whether nonprogrammable "languages" like IMPRESS, hpgl, etc., are "better", "faster", etc., but there is still one fact that remains undisputed: PostScript is the only languate that exists today on a wide range of devices from a wide range of manufacturers (true, the LaserJet's language is emulated by lots of printers, but read on) at a wide range of resolutions: 200 DPI up to 2540 DPI. PostScript is the only PDL implemented on a typesetter available today; Compugraphic is expected to announce an Interpress RIP for their 9600, but that hasn't happened yet. The Lino 100/300 have been running PS for almost a year and a half. This may not be a big deal to some of you, but we've done several books. The first was done on an Autologic APS-5 using ditroff, with proofs going to an Imagen Imprint-10 and a Xerox 9700. The next two were done on LaserWriters; after them, the publisher said "No more laser printer masters! We want phototypeset camera-ready." We were forced to use Linotronics for subsequent camera-ready pages. As a language, PostScript probably isn't the end-all do-all of the typesetting/publishing world; however, due to Adobe's energy and commitment to the language, it's become entrenched as the only viable one for those of us that require high-end output from time to time. Also note that PostScript is the only PDL available today at 400 and 600 DPI on plain paper (or anything else for that matter). Pat Wood etc, etc, etc.
phw@phw5.UUCP (04/15/87)
>>Since there are few people who have actually seen an Interpress and/or DDL >>printer, it's hard for anyone to say anything that isn't based on some >>manufacturer's claim or second-hand knowledge. >I think Interpress printers have been on the market since 1982. >We got our Xerox 8046 in January, 1985. Note that I didn't say that Interpress is new or that it's not available or that NOBODY has it; I'm merely stating that not many people have it due to the market's reluctance to accept it and Xerox's reluctance to market it. >>[...] Xerox says that Interpress is designed for speed and is faster than >>PostScript. Considering that the only version of Interpress that's >>available now doesn't do graphics, only text and scanned images (no >>vector graphics, clipping, or rotation of text), I can see why it's fast. >Ours does vector graphics, clipping, rotation of text, and a few other >things. It does have a few weaknesses. Text can be rotated only in >the case that the printer possesses pre-rotated font files. (But how >often do you use fonts at rotations other than 90 degrees?) It doesn't >do arbitrary curves. Our Xerox workstation software computes the >arbitrary curves and uses line graphics to render them...a kludge, but >users don't care where the math is done. (We use Interpress 2; not 3.) Okay, I didn't realize that Interpress 2 was out in the general market. I am pretty sure that Interpress 3 isn't out yet--anyone know differently? As for rotated and special effect fonts? We use them quite a lot. How does Interpress fair with halftones, etc. We've been quite happy with PostScript's halftoning capabilities. >I wouldn't say that the 8046 is a fast printer. Fast is relative; PostScript isn't exactly a screamer! Nobody can really do a true benchmark of PS vs IP, since you'd have to have them implemented on the same processor doing the same things to the same print engine. >I think DDL was invented mainly in the hope of chilling postscript. Now now, I think Imagen had some good ideas to bring forth with DDL, and I think they feel they have a superior language (which they may). I'm sure they did take into account the fact that having their own PDL may be less expensive in the long run than paying royalties to Adobe for PostScript, and that if it were to become a standard, they might make some big profits. The problems I see with DDL are political: 1. They sell laser printers, making them competitors with anyone that adopts the language. Adobe doesn't manufacture laser printers; they merely design controllers for them. Printer manufacturers still compete with each other when they sell PostScript printers, but they do that anyway; at least they don't compete directly with Adobe. Perhaps this is a subtle difference, but I think it's an important one. 2. Imagen does other things than just market DDL. For some time, Adobe did nothing but market PostScript. Even now, everything they do is to further the acceptance of PostScript, for example, look at all the fonts they're doing, and look at Illustrator, which produces PostScript output. Is there a comparable program for Interpress or DDL printers? Everything Adobe does is geared towards pushing PostScript; you can't say that about Imagen. >I sure wish Imagen would offer a Postscript emulator for the IP/II >series of printers. Then (I think) we'd have the best of all worlds. Rumor has it that Imagen is in fact developing a PostScript to DDL converter. Pat Wood the usual long title the usual multi-path address the usual corporate disclaimer