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Re: CUPS question



On Wed, Jun 06, 2001 at 10:44:06AM -0700, Mike Pfleger wrote:
| On Wed, Jun 06, 2001 at 12:32:06PM -0400, D-Man wrote:
| > 
| > I haven't done any configuring of ethernet printers, but I do have an
| > older Laserjet IIIp and an old Seiko ColorPointPS.  I have found that
| > if I send PS Level2 data to the printer the LED will flash as it gets
| > data, but the LCD will display "Flushing PS Job" and once the spooler
| > has sent all the data nothing happens.
| <SNIP> 
| 
| Sorry to intrude, but I couldn't let this fly by without asking a quick
| question.  What could you tell me about using a IIIp with CUPS?  I have
| been giving some thought to moving to CUPS, as I'd heard that it gives
| PCL5 support.  I don't have a memory expansion in my IIIp, so "larger"
| files cause it to hang and display MEM OVERFLOW in the display.  This
| is _really_ annoying, as I can send vastly larger files to it from a
| <cough> windoze <cough> box.

Supposedly CUPS is great at see what type of file you are trying to
print, then sending it through the necessary chain of filters to get
an output that is satisfactory for the printer to handle.

I haven't spent enough time studying the various configuration options
yet and have thus only been printing plain text and PS level1.
Ghostscript does generate good PCL5 output, though.  (I used it on a
RH box which I configured using 'printtool' -- it worked very well)

My IIIp has 5MB RAM and a PS Level 1 expansion card (all came with it
-- I got it as a hand-me-down).


One of the key parts of a CUPS configuration seems to be the PPD file.
CUPS comes with a "laserjet.ppd" file, but I assume that is intended
for newer laserjets (with PS L2, PCL6 or higher, etc).  Just for kicks
I tried hacking my (even though I don't know anything about their
spec) and changed  the LanguageVersion line from "2" to "1".  I
printed some Postscript that I got off a web site, and it came out
beautifully.  I don't know if it was L1 or L2, but L2 PS just says
"Flushing PS Job" in the LCD.  The really interesting thing is that
the LCD _looks_ like it is in PCL mode while I am printing PS now.  (I
used pdftops by hand last night to convert the PDF's of the class
notes I got to PS L1 before spooling them)

The other key part is having the filters.  CUPS uses
/etc/cups/mime.types as a list of rules to determine the MIME type of
a file, then /etc/cups/mime.convs as a list of filters that convert
from one type to another.  If I read the spec for the interface of the
filters, it shouldn't be too hard to make a light wrapper (in Python
or SH) around Ghostscript to convert PS to PCL5.

The main issue I seemed to have was in getting CUPS to actually run
the filters.  I believe that was related to the PPD file not
accurately describing what my printer can handle, so CUPS didn't think
it needed to filter the output.

I need to do some more testing and experimentation and studying of
documentation before I can accurately determine if CUPS works really
well, or works only if you set it up right.  (And then I will know how
to set it up right :-))

-D



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