data sitting in spool and not printing

[Helge Blischke]

Bill Greganti wrote:

> Hi everyone,
> 
> I have a client that has just upgraded from an old IBM AIX server to a new
> RHEL 6 server. I installed CUPS on the server to setup printing to 2
> serial dot matrix priners and 1 network printer.  The printers work from
> the GUI and command line.
> 
> They are using a software package that runs on T-bred, but other than that
> I don't know much about it.  We use the software company's support for
> that, but they say this is a Linux problem and they are not sure how to
> fix it.
> 
> My problem is when they print from the software package it opens the print
> job and spools some data to the printer, but does not close the print job.
>  So the spooling never finishes and nothing comes out of the printer. For
> example, when they print checks, it supposed to print an alignment pattern
> first.  They verify that the alignment is good, and then continue the job
> printing all the checks.  But the alignment pattern gets stuck in spooling
> and doesn't print until they exit the check module of the software.
> 
> They say this is not a problem with the software as it worked fine on AIX.
>  They tell me I need to turn off spooling, which I don't see any way to
> do.
> 
> Any help or suggestions would be much appreciated.
> 
> TIA,
> Bill

Well, in the ancient times of serial printers it was quite common to flush 
data to the printers character by character or at least at line breaks.
As I see it, you don't have any chance to configure CUPS to work that way - 
it is contrary to the whole design (in fact, the design of any spooling 
systems).

If your software prints using an executable command (like lp or lpr or 
whatever its name is), you probably could replace it by a script (shell or 
Perl or Python) that divides the possibly infinite data stream into separate 
chunks whenever a certain (adjustable) time of inactivity has elapsed or by 
catching certain signals you can trigger by keystrokes etc., or by scanning 
the data stream for certain byte sequences which mark the possible 
boundaries.

Helge