Printing question

[Tommy Trussell]

On 2/2/06, Albert <albertwagner at cox.net> wrote:
> R Kimber wrote:
> > If a job has been sent to the printer, but is then removed from
> > the printer queue before it has been completed (because it is not
> > printing correctly) and the printer switched off, what happens to the
> > job?
> >
> > I would expect it to have been deleted, but on switching on my printer
> > again, it continues to spew out unwanted pages, some with a line of
> > what looks like postscript on them, so it must be spooling a file to
> > the printer.
> >
> > How do I stop this behaviour?  I.e. how do I abort the job when the the
> > print system shows no jobs being printed?
> >
> > Ubuntu 5.10, 2.6.12-9-amd64-k8-smp
>
> Maybe your printer has an internal memory buffer.  I suspect most do.  I
> think that the print queue reflects what has been sent to the printer,
> not what has actually been printed on paper.  My old HP Deskjet 540C
> acts this way.  Try unplugging the printer. Just turning it off probably
> won't work.

Some PCs also seem to have some sort of buffer on the parallel port --
I had a Compaq Pentium 200 set up as a print server, and while I was
testing a driver in CUPS for an old Canon inkjet, I would find that
not only would I have to turn off the printer but I would reboot the
CPU to clean out the buffer. Quite annoying! I never found any command
that would purge the buffer, but I found I could unload and reload the
parallel port kernel module to purge the buffer. That was effective,
but much more complicated than a reboot!

(I ultimately gave up on the free gimp-print driver when I discovered
a commercial driver that supported the old Canon inkjet very well.)