> > > The problem is that CUPS doesn`t show the parallel port in the list
> > > of available connections...

Okay, I added some debugging to cups-1.1.15/backend/parallel.c

$ ./parallel
here in NetBSD
trying /dev/lpt0
parallel: /dev/lpt0 (16): Device busy
trying /dev/lpa0
parallel: /dev/lpa0 (16): Device busy
trying /dev/lpt1
parallel: /dev/lpt1 (13): Permission denied
trying /dev/lpa1
parallel: /dev/lpa1 (13): Permission denied
trying /dev/lpt2
parallel: /dev/lpt2 (13): Permission denied
trying /dev/lpa2
parallel: /dev/lpa2 (13): Permission denied

It does open(device, O_WRONLY).

So the problem is error 16, "Device busy".

Sometimes, when I turn on or off the printer and run ./parallel at the
same time (within the one second), it successfully opens the /dev/lpt0 or
/dev/lpa0 (and no "Device busy).

Is "Device busy" a valid error for assuming that the parallel port is
never available for configuration for future printing?

Any comments or advice before I submit patch for pkgsrc and back to cups
developers?

(On a side note, open(2) manual doesn't mention "EBUSY".)

   Jeremy C. Reed
   http://www.reedmedia.net/