In one of the schools I work at, I was told that users are having trouble printing -- that the print queues keep getting jammed, and they are prompted for a password that they don't have to unjam them.
Our users are using Macs running OS X 10.5.7. The computers are printing directly to a network printer (ie. without going through a print server first).
I found out how to determine which machines have problems:
lpstat -o -p
shows which jobs are in the queue, and states things about the printers. On a problem computer, it ends with this:
printer CJHS_WestLab_HP1320 disabled since Wed Dec 16 09:35:54 2009 - /usr/libexec/cups/backend/lpd failed
I think the reason that print jobs are failing is because somehow, the printer is defaulting to using size A4 paper -- and students here use US Letter-sized paper exclusively. The job then goes to the printer, which starts blinking until you hit one button to print anyway, or another to cancel the job.
I have two questions:
- how can I enforce a US Letter page size (in a script?)
- can I let users clear the queue themselves? enable them to pause and unpause printers?
- if not, is there a good script to run to purge the queues?
I can see that as an admin, I can purge print jobs in these ways:
- I found a nice script that'll clear the queues every two minutes -- but surely there is a more elegant solution to the problem!? [I'll take something that works over something that is elegant, but elegant + works == goodness].
- And, with just a little more searching ... cancel -a -. It still prompts for someone who belongs to the lpadmin group, and it doesn't resume stuck printers ... but it is really useful to know, for fixing things as an admin.
I also found this Mac OS X hint that negates the requirement for users to be in the lpadmin group by editing /etc/cups/cupsd.conf . This sounds great -- I'm just worried that it'll be stomped on by a software update.
Still, I can't help but feel that there is something I'm overlooking, and that there is a better solution to this problem. (And I'd love to know why the default page size is A4, and how to fix that.)