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From: ted@mitre-bedford.ARPA (Edward J. Ede)
Newsgroups: comp.lang.postscript
Subject: Re: Host software alternatives to PS engines?
Message-ID: <39964@linus.UUCP>
Date: 16 Sep 88 15:51:04 GMT
References: <AXA4Jay00VsMI1MUcA@andrew.cmu.edu>
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Reply-To: ted@mbunix (Ede)
Organization: The MITRE Corporation, Bedford, Mass.
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In article <AXA4Jay00VsMI1MUcA@andrew.cmu.edu> bob+@andrew.cmu.edu (Bob Sidebotham) writes:
>For people with relatively modest volume printing requirements, it would seem
>ideal to be able to buy a cheap printing engine, without PostScript support,
>and do the PostScript to raster conversion in the host computer.  Does anyone
>know if there is any such product on the market, or anticipated to be?  If

IBM does their PostScript translation on a card in a PC, then blasts
the bits to an attached engine.  I'm not sure why they chose to do it
this way, maybe to transfer bits from the card to the screen.  I can't
imagine that this approach is cheaper than a "normal" PS printer.  I
think you're asking about native PS interpretation though.

>someone could build an effective implementation of this software, I'm sure it
>would have a ready market. Given the existence of Display PostScript and other
>PostScript interpretors, it seems that it might almost be possible to build
>something like this with off-the-shelf components.  I'd even be willing to buy
>such a package from Adobe,if they charged a reasonable price and didn't try to
>bundle too many high-priced fonts with it.
>
>I'm assuming that dumb printers are available that can actually be hooked upto
>your machine: I'm told that (1) Canon laser printing engines can be had for as
>little as $900 and (2) the Mac's SCSI bus is fast enough to drive the laser
>printer directly.  I don't know whether a dumb-enough interface is available
>for the printer, however (that is, an interface without any added-value(diablo
>mode, etc.) to drive it's price up).
>
>Is there something technically wrong with this suggestion?

First of all, your machine would need a lot of memory to image the
entire page.  Display PS is feasible because the resolution of most
screens is lower than the standard 300x300 dpi.  A 300x300 dpi printer
would require 9 times the memory of a 100x100 screen.
(300x300x8.5x11) = ~ 1 Megabyte.  You could do the page in passes, but
that would require multiple interpretations of the PostScript.

Secondly, PostScript is an extremely powerful language, and
non-trivial to interpret.  Your Mac/PC would be tied up for quite a
while while imaging the pages, reducing your productivity.  Look
through the Red Book and examine what all of the operators can do.
They don't stick 68020's in these printers for no good reason.

With PostScript in software, it would be easier for a hacker to
reverse engineer crucial parts of the software.  (e.g.  the "eexec"
operator, font rendering algorythms.)  I'm sure Adobe wants to
protect this for as long as they can.  (I realize that one could pull
the chips from a PS printer, but that's beyond the means of many
people.) 

You can buy a NEC PostScript printer for about $3,300.  I don't think
that's unreasonably expensive for what you get.  

>Bob Sidebotham
>Carnegie Mellon University

Ted Ede -- ted@mitre-bedford.arpa -- The MITRE Corporation -- Burlington Road  
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