Jon,

Of course, I misspoke.  Of course, CUPS was installed by default.  I would
never have been able to print at all without it.  Where I said "without
CUPS running" I meant the CUPS print server daemon cupsd.

The problem remains that although the Gnome desktop offers several tools
for configuring printing, none of them functions without cupsd running.

The daemon was not running out of the box, and it was never running in
my previous SL system.  This is fine: it SHOULDN'T be running by default,
because it isn't necessary for each machine to be a print server.

But the effect is that a Gnome user with a remote network print server can
click around until they're blue in the face, and nothing will ever print.
They must discover and issue a non-GUI command (or else possibly start
the CUPS daemon...but that isn't clear--it certainly isn't to me, because
I never got that to send print jobs either.)

The SL distro desktops should provide a clear GUI for connecting to a
remote print server without starting cupsd.  This should be very easy to do.

Cheers!

On  6.01.08, Jon Peatfield wrote:
> On Sun, 6 Jan 2008, Jeffrey Anderson wrote:
> 
> >On Sunday 06 January 2008, Steve White <[log in to unmask]> wrote:
> >>My colleague can configure his SL5 workstation to print without CUPS,
> >>using KDE.
> >>
> >>I gather from this discussion that the SL5 distro Gnome desktop does not
> >>provide a way to configure the system to print directly to a networked
> >>printer *without CUPS*, although the KDE desktop does.
> 
> You need *CUPS*, you may not need a CUPS server (cupsd) on the client 
> machines. Well technically I suppose you could still run lprng or similar 
> but CUPS seems to have taken over most of the world...
> 
> >lpoptions -d MYPRINTER
> >
> >should set the default printer for the system.  It doesn't really have
> >anything to do with your choice of desktop.  The gui desktops may or may 
> >not
> >include a graphical thingy to perform this, but that is certainly not
> >necessary.
> 
> Just to be more confusing for those who don't see the difference, 
> lpoptions sets options for the user running the command (by updating 
> ~/.lpoptions usually).  However when run as root it sets system-wide 
> defaults (cups/lpoptions).
> 
> The lpadmin command can also be used to set a 'system default printer' 
> though on a multi user system that may not make much sense.  We set our 
> system default to a dummy printer queue because without that one poor 
> printer used to get all the printouts from people who hadn't set a 
> default...
> 
> The usual (sane) default config for the cupsd (as run on client machines!) 
> is set to listen for IPP printer adverts and use those to populate the 
> list of available printers.  This is the default state in (say) recent 
> versions of SL or Fedora since it means that after connecting to a random 
> network using CUPS it will pick up lists of printers without needing any 
> special configuration (which simplifies support!).
> 
> On (say) Ubuntu 7.04/7.10 the default cupsd config/setup doesn't listen 
> for the printer adverts so that needs to be enabled if you have a network 
> with printing support provided by CUPS servers.
> 
> Since MacOSX 10.2 Apple have used CUPS for printer support though they had 
> a slightly non-standard version - they recently bought the company who own 
> CUPS so that difference may have already gone.  The MacOSX CUPS used to be 
> set to listen for IPP adverts so would work out-of-the-box.
> 
> However since MacOSX 10.5 they have altered the cupsd config so that it no 
> longer listens (by default) for the CUPS IPP printer adverts.  It now 
> defaults to only finding Bonjour/Zeroconf printers although telling it 
> also listen for IPP adverts is pretty simple to do - just like it is on 
> Ubuntu 7.04/7.10.
> 
> Bonjour/Zeroconf may one day avoid the need for the broadcast IPP adverts 
> etc but I have no experience of that myself.
> 
> For users' own UNIX/Linux/OSX machines (laptops etc) we strongly suggest 
> that were possible they run a local cupsd to automatically pick up 
> printers from the adverts we arrange to send out.
> 
> However, for our desktop Linux/UNIX machines (the ones under our control) 
> we just arrange for the cups/client.conf to point at our central print 
> server.
> 
> In part this is because I can avoid needing to run yet-another-service on 
> every desktop machine but also because on this network they would see 
> printer adverts from CUPS servers we don't (and can't) control...
> 
> So the short summary is:
> 
>   If you don't want to run cupsd and you have a single CUPS server then
>   you *can* edit cups/client.conf to point at the server.  If you have
>   edited cups/client.conf then a local cupsd will not be used even if it
>   is running (*).
> 
>   If you have printers provided by multiple CUPS servers or use the
>   machine on more than one network or have locally attached printers then
>   you need to run a cupsd.
> 
>   cupsd can be configured to listen for CUPS IPP printer adverts if you
>   want (usually the default), and/or be told to poll a set of servers to
>   obtain the list of printers or not do either.
> 
> (*) Of course you can set CUPS_SERVER=127.0.0.1 to temporarily override 
> the client.conf. If you have a server set in client.conf then compare the 
> output of:
> 
>   lpstat -v
>   CUPS_SERVER=127.0.0.1 lpstat -v
> 
> The latter will show any printers that cupsd has found from adverts etc.
> 
> BTW we currently use (modified) cups-1.3.4 based central CUPS servers (on 
> SL3x) to avoid some of the problems caused by some clients seeming to 
> cause cups-1.1.x to crash or stop answering requests.  Our CUPS servers 
> still seem to occasionally die but far less often since we updated.  Are 
> we the only ones who see problems with cupsd crashing (or freezing)?
> 
> -- 
> Jon Peatfield,  Computer Officer,  DAMTP,  University of Cambridge
> Mail:  [log in to unmask]     Web:  http://www.damtp.cam.ac.uk/
> 

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