[Inkjet-list] resetting printer

Robert L Krawitz rlk at alum.mit.edu
Tue Feb 5 03:56:52 PST 2002


   From: "Mark VanderWiele" <markv at us.ibm.com>
   Date: Mon, 4 Feb 2002 20:50:26 -0600

	 >Without the additional
	 >knowledge of the beginning and end of graphics segments, you send
	 >extra unprinted data.  However it always aborts without eating the
	 >next job.  Optimally, there is a method to tell the (lp,usb,...)
	 >port to throw away buffered data without letting another job in
	 >during pooled printer situations.

   >Same problem: only the driver knows what the safe boundaries are.

   Yes, I agree. given a clean slate, how do you think the problem
   should be solved?

My preference would be for a system where the job data is converted to
raw printer format only at the very end.  If we accept that as a
premise, then everything becomes straightforward; either an in-band
signal (special token in the data stream) or an out-of-band signal (a
semaphore of some kind or a literal UNIX signal) tells the driver that
the job is being aborted and that it should clean up and exit.

What if the user insists on sending a job in raw format?  There are
two possibilities: either the data still goes through the driver,
which is responsible for parsing the data stream on the fly, or such a
job cannot be aborted.  The spooler should allow refusing raw jobs on
a per-queue basis, in that case.

-- 
Robert Krawitz <rlk at alum.mit.edu>      http://www.tiac.net/users/rlk/

Tall Clubs International  --  http://www.tall.org/ or 1-888-IM-TALL-2
Member of the League for Programming Freedom -- mail lpf at uunet.uu.net
Project lead for Gimp Print/stp --  http://gimp-print.sourceforge.net

"Linux doesn't dictate how I work, I dictate how Linux works."
--Eric Crampton




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