A.P. Lawrence

netcat

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From: Jeff Liebermann <jeffl@comix.santa-cruz.ca.us>
Subject: Re: Netgear print server
Date: Sat, 15 Jun 2002 08:07:18 -0700 References: <pSzK8.32$ir.47310@news.onenet.net> <shh1guot6e7r5thpkg52j8ttnrlrv6pr54@4ax.com> <rg5M8.33$ir.51703@news.onenet.net> <3d097bf8.71609290@news.highway1.com.au> <3D09CEAA.9030400@aplawrence.com> <3D0A9290.5000600@steinmetznet.com>

On Fri, 14 Jun 2002 23:04:17 GMT, Robert Steinmetz
<rob@steinmetznet.com> wrote:

>> True.  But..  netcat works better. 
>> /SCOFAQ/scotec7.html#getnetcat
>
>I have used LPR on many systems, without problems. Why is netcat better? 
>I have seen many posts advocating it use, but no simple explanation of why. 

Methinks you have to roll back the clock about 4-5 years, when OSR5
LPR/LPD was seriously buggy.  The most common problems that I saw were
hangs when printing a large number of small jobs, and high cpu
utilization.  I've experienced both with LPR/LPD.

The alternative, HPNP for HP print servers, was worse.  It had locking
problems, would leave garbage all over /tmp, would hang if you print
to an off-line printer, and belch bogus error messages if SNMP status
were not available from the print server.  I also had some difficult
to reproduce problems that resulted in continuous retries with a
corresponding deluge in network traffic.

In 3.2v5.0.5, there were also some "scoadmin" printer configuration
problems that made printers disappear if added after an LPR/LPD
configured printer.  lpstat -t would sometimes fail to show all
printers and often stall for extended periods waiting for a
configured, but powered off LPR/LPD printer, to come online.

AFAIK, the LPR/LPD, scoadmin, and lpstat problems were solved in some
update to 3.2v5.0.5 and remain fixed in 3.2v5.0.6.

However, 4-5 years ago, there was no suitable solution to the reliable
printing problem.  I was looking for something that preserved the
print spooler system and the print spooler scripts, but communicated
directly with the print server.  Kevin Smith supplied the answer with
his "netcat" program.  I'm not much of a programmist, so additional
help was needed to modify the scripts to use netcat and to add the
/etc/printers configuration file.

I have a customer that was printing about 2000 checks per day.  The
program creates on print job per check resulting in a huge number of
print jobs that had to work perfectly.  We started with LPR/LPD, but
that kept hanging.  We switched to HPNP, but ran into a wide
assortment of stupid problems (inability to recover from an off-line
condition, print server bugs, trash in /tmp, job counter errors, etc).
The system would also bog down somewhat when printing.  When I setup
netcat, the hangs stopped, off-line recovery functioned, the print
server bugs were not an issue, and nobody even notices when it was
printing.  We also noticed an unexpected printing speed improvement as
there is apparently some overhead to setting up a print job using
LPR/LPD and HPNP in the print server.

Try it.  You'll probably like it.

-- 
Jeff Liebermann  150 Felker St #D  Santa Cruz CA 95060
(831)421-6491 pgr (831)426-1240 fax (831)336-2558 home
http://www.LearnByDestroying.com   WB6SSY
jeffl@comix.santa-cruz.ca.us   jeffl@cruzio.com

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