[TriLUG] question about redhat-config-printer, lpd, and cups

[Lisa Lorenzin]

hi all!

i've been playing with my printing setup, and i have some questions about 
the relationships between lpd, cups, and redhat-config-printer.

i started out using lpd, since that's the default in 7.3.  our laser
printer (HP LaserJet 4L - a dozen years old at least & still going strong)
is hanging off mike's linux server; he has it shared via samba.  i added
it via redhat-config-printer-gui (aka printconf-gui), and everything Just
Worked.  i've been using it for several months with no problem; it was the
only printer configured, and i had it selected as the default.

in the past few weeks, i've acquired an HP PSC 2210 inkjet, and have been
trying to get it working on this box.  it works fine on RHL9 (on another
system), but we can't get it working under 7.3 - mike and i have each
spent about 5 hours on it, to no avail.  i currently have an entry for it
in printconf-gui, as a result of our efforts, but printing to it doesn't
work yet.  (cups queues a print job, but it dies at ghostscript - more
debug needed.) in the course of trying to get it to work, i switched from
lpd to cups using redhat-switch-printers.

unfortunately, something i did in the course of trying to get the psc2210
working had the side effect of setting it as the default printer.  which
should be easy to fix, right?  just go in printconf-gui and select hp4l as
the default printer and click Apply.  except that it says "lpd restart 
successful" and starts up lpd, rather than restarting cups.

so now the default checkmark in printconf-gui indicates that the hp4l is 
the default printer, but all indications from both lpd and cups indicate 
otherwise:

[root at home7 rc3.d]# lpstat -d
system default destination: hppsc2210

[root at home7 rc3.d]# lpq
hppsc2210 is ready
no entries

so i poked at the redhat docs[1] (when all else fails, right?) and
discovered that redhat-config-printer-gui is only for use with lpd.  
d'oh!  so the obvious solution (to me) is to kill lpd again and use
lpadmin -d to change the default printer.  which does have the desired
effect:

[root at home7 rc3.d]# lpadmin -d hp4l

[root at home7 rc3.d]# lpstat -d
system default destination: hp4l

[root at home7 rc3.d]# lpq
hp4l is ready
no entries

which leads to my questions.  when i changed the default printer setting
in printconf-gui, the default printer setting in lpq didn't get changed.  
(and neither did the default setting in lpstat, but i didn't expect it
to.)  i would have expected that the default printer for lpq would have
changed to hp4l, but the default printer for lpstat -d would have stayed
hppsc2210 (since i'd changed and restarted lpd, but hadn't done anything
to change cups.

and conversely, when i changed the default printer setting with lpadmin
-d, i don't understand why the default printer for lpd got changed along 
with the default printer for cups...

adding to my confusion - when i go into the cups webUI and set up the hp4l 
there, i end up with 3 entries:

hp4l  
HP LaserJet 4L, Foomatic + ljet4        
Description: HP LaserJet 4L
Location: hp4l at 10.1.1.2
Printer State: idle, accepting jobs.
Device URI: lpd://10.1.1.2/hp4l

hp4l-remote 
HP LaserJet 4L, Foomatic + ljet4 on neo 
Description: Created by redhat-config-printer 0.6.x
Location: HP LaserJet 4L
Printer State: idle, accepting jobs.

hp4l at neo 
HP LaserJet 4L, Foomatic + ljet4 on neo 
Description: Created by redhat-config-printer 0.6.x
Location: HP LaserJet 4L
Printer State: idle, accepting jobs.

i figure that's just the way cups does things, and i'll learn more about
that as i get more familiar with cups.  but what does puzzle me is: if
redhat-config-printer-gui is only for use with lpd, then why does the
description field have "Created by redhat-config-printer 0.6.x" in it?  
since it was defined in cups, i don't understand why redhat-config-printer
would have anything to do with it.

i'd really like to understand what's going on here, since it looks like
lpd, cups, and redhat-printer-config are more entangled with each other
than i had thought...

							lisa



1: http://www.redhat.com/docs/manuals/linux/RHL-7.3-Manual/custom-guide/ch-printing.html





-- 
lisa lorenzin  |  lorenzin at 1000plus.com  |  http://www.1000plus.com/lisa/
of what avail is an open eye if the heart is blind? - solomon ibn gavirol