A.P. Lawrence

Best of the Newsgroups: netcat vs. HPNP (hpjetdirect) network printing

If this isn't exactly what you wanted, please try our Search (there's a LOT of techy and non-techy stuff here about Linux, Unix, Mac OS X and just computers in general!):

From: Jeff Liebermann <jeffl@comix.santa-cruz.ca.us>
Subject: Re: Are there simply inharent problems with SCO 5.0.6 IP printing ? Message-ID: <ujiitv4k1pri0delo77m04kl3mi3gr2pl7@4ax.com> References: <8b8c1$3fd8ab24$42a6716f$31091@msgid.meganewsservers.com> <00bf01c3c00f$c6d07ae0$6700000a@venmar.com>
Date: Fri, 12 Dec 2003 05:13:20 GMT

On Thu, 11 Dec 2003 17:54:07 GMT, Fabio Giannotti <fabiog@venmar.com>
wrote:

>We use Jet Directs with a great deal of success.  First, let me state, much
>to the displeasure of most of the people on this list, that we do NOT use
>netcat.

Hiss, boo, etc.  I like netcat.

>We use the HP stuff built in to SCO and have never had any problems
>printing.

Hmmmm... HPNP.  No garbage left in /tmp after each print job?  No
spooler lockups when printing a large number (>500) of simultaneous
small files?  No difficulties autoswitching between Postscribble and
PCL?  No failure to restart if rebooted while printing?  No exessive
LAN traffic if printers with one model of JetDirect card ran out of
printer and HPNP would poll the printer thousands of times per second?

>One note, we found that on multi-port Jet directs if the printer on port 1
>is in an error condition, you can not print to ANY of the printers on that
>Jet Direct.  (This appears to only happen from SCO, not from Windows.)  We
>solved that problem by never using multi-port units.

There are two possible fixes for that problem.
1.  Early versions of HP JetDirect firmware had a problem that
simulated the effect.  It would also happen with Windoze printing so
you probably don't have to worry about that one.  However, make an
effort to check if your firmware is up to date.
2.  SCO HPNP uses SNMP to determine print server status.  HPNP is
stupid and only checks the status of the first printer.  Therefore, if
you take the first printer offline or it runs out of paper, everything
stops on the 2nd and 3rd port.  The easy fix is to rename the program
/bin/getone.  This is the SNMP request binary.  If HPNP can't find
SNMP, it assumes that the all the printers are always ready.

Admitedly, HPNP and LPR/LPD are suitable for normal printing jobs.
However, none of my customers are normal or they wouldn't hire me to
do battle with their systems.  For example, one prints 1000 to 2000
payroll checks per day.  There's nothing like a print queue with 1000
jobs waiting to test the stability of a print system.  I switched to
netcat after HPNP and LPR/LPD screwed up far too often.

Also admitedly, netcat has its limitations. It's a direct dump to an
IP socket on the print server.  Therefore, it does not work with print
servers that only support LPR/LPD, or do not have HP port 9100
JetDirect emulation.  There is also no flow control.  It relys on the
TCP/IP flow control (source quench) to prevent overflowing the print
server buffer.  This works well with decent print servers (HP) and
screws up badly with buggy print server firmware (Netgear PS101).  Try
it, you might like it.

-- 
# Jeff Liebermann   150 Felker St #D Santa Cruz CA 95060
# 831.336.2558 voice    http://www.LearnByDestroying.com
#                           jeffl@comix.santa-cruz.ca.us
# 831.421.6491 digital_pager  jeffl@cruzio.com     AE6KS

Enter your email address for automatic notification of new posts here
(be sure to whitelist 'feedburner.com' if you use spam filtering)

/Bofcusm/2411.html copyright 1997-2004 (various authors) All Rights Reserved

Have you tried Searching this site?

Unix/Linux/Mac OS X support by phone, email or on-site: Support Rates

This is a Unix/Linux resource website. It contains technical articles about Unix, Linux and general computing related subjects, opinion, news, help files, how-to's, tutorials and more. We appreciate comments and article submissions.

Publishing your articles here