RE: [TCLUG:9256] print server concepts

["Carl Patten" <cpatte@trimodalinc.com>]

Ah, network printing.  I wallow in network printing.  Let me try to answer
at least a few of your questions.

> -----Original Message-----
> From: Tim Wilson [mailto:wilson@chemsun.chem.umn.edu]
> Sent: Monday, October 18, 1999 4:46 PM
> To: tclug-list@mn-linux.org
> Subject: [TCLUG:9256] print server concepts
>
>
> Hi everyone,
>
> Here's a question that I've been wondering about off and on. I figure it's
> something that other people would probably be interested in too. So here
> goes...
>
> Let's say we have a simple LAN, 'server', 'workstation', 'printer', and
> 'printserver.' The printer has a JetDirect card (i.e., its own internal
> print server). I'm trying to figure out the basics of how the network
> printing works. I understand that, strictly speaking, the JetDirect card
> eliminates the need for a special print server (especially given the
> simplicity of this example). But I've also heard that more complex
> networks benefit from having a separate machine doing the print serving to
> the JetDirects.

Yes, even the most advanced JetDirect cards can only accept one connection
at a time.  Hence if you get more than one client printing directly to the
JetDirect card, jobs have a tendency to time out or have their connection
reset, especially dumb Windows clients.  That's the main advantage of having
a print server in the middle: it can hold jobs in its queue until the
JetDirect printer is ready to accept them.

> Anyway, here are some questions.
>
> 1. Does 'workstation' have to run lpd, or just 'printserver'?

AFAIK, you do need lpd on 'workstation' to properly interpret your
/etc/printcap file and send the jobs to the right spot.  If you're using
Samba on 'printserver' you can use the smbprint command instead, though I
haven't tried that much.

> 2. Does having one print server for multiple printers mean simply that
> there are multiple print queues on that machine or is it more complicated
> than that?

That's all there is to it.

> 3. How would a print server print to multiple printers if the printers
> don't have JetDirect cards (or the equivalent)? Would you have multiple,
> physical parallel connections to the printers? If so, wouldn't that mean
> that all of the printers would have to be physically close to one another?

Not necessarily; Digi, for instance, sells products that let you add serial
and parallel ports across an Ethernet network and make it seem like they're
directly connected to your print server.  We use Digi PortServer IIs here at
work to run our few remote serial printers.  They're damn pricey though, and
last time I looked the Digi RealPort software didn't run on Linux.

You could always set up a network of cheap 486 Linux boxen, each hooked to
one parallel-port printer.  That would give you the queuing advantage and
might be cheaper than getting a JetDirect for each one.

> 4. To configure printing to 'printer', would I set up printing to
> 'printserver' and have that redirect printing to 'printer'?

Assuming you're on 'workstation', you would set up printing to host
'printserver' and queue 'printer' in /etc/printcap.

>
> For whatever reason, I haven't got the hang of this network printing stuff
> yet. What I've got running works, but I feel like I don't understand it,
> and I'd like to add another printer and make everything work well
> together. Any other hints?

It can get very complicated in a mixed environment.  My advice is to go with
what works for other people.  Get printers and print servers that are KNOWN
to work with Linux.  So much stuff can go wrong with network printing that
I've become ultra-conservative if not downright paranoid in this one area.

--
Carl Patten
Systems Administrator
Trimodal Inc.