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From: denise@cwi.nl
Newsgroups: comp.laser-printers
Subject: Re: Adobe Transcript and 4bsd lpc abort
Message-ID: <8707151328.AA02324@brillig.umd.edu>
Date: Wed, 15-Jul-87 10:09:18 EDT
Article-I.D.: brillig.8707151328.AA02324
Posted: Wed Jul 15 10:09:18 1987
Date-Received: Fri, 17-Jul-87 06:01:19 EDT
References: <13447@teknowledge-vaxc.ARPA>
Sender: daemon@ucbvax.BERKELEY.EDU
Reply-To: mcvax!cwi.nl!denise@seismo.CSS.GOV (Denise L. Draper)
Distribution: world
Organization: Centrum voor Wiskunde en Informatica, Amsterdam
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Approved: laser-lovers@brillig.umd.edu


I responded to this about a month ago, but it never showed up in the
newsgroup, so let me try again:

In article <13447@teknowledge-vaxc.ARPA> mkhaw@TEKNOWLEDGE-VAXC.ARPA writes:
> When I do a "lpc abort ps", the lpd daemon associated with my postscript
> printer dies, but the Transcript filters that are the children of the
> killed lpd don't die.  Is that expected, and if so, why?  I expect lpc
> abort to get rid of all of them so I don't have to do a "ps" to look for
> the filters and kill them myself.
>
> Mike Khaw

Simply put, this is a Transcript bug.  The source for lpd clearly states that
all filters should be killable, but pscomm creates children that ignore
signals.  The reason they do this is that pscomm works as two processes
which communicate with each other, and if one were to die, the other
would wait -- forever.

The setup (in pscomm) of having two communicating processes has several
problems.  After trying for awhile to fix some of them, I simply gave up
and wrote a new pscomm.  My version uses only one process, and uses the
bsd select() call to handle `asynchronous' communication with the laser
writer.  So far (which is four months of heavy usage), we have had no
problems with it.  If you are interested, send me some e-mail. (Because
I borrowed heavily from the original Adobe source, I can only distribute
this to people who already have Adobe source).

Denise Draper
denise@mcvax.cwi.nld
...!seismo!m<2e by!gON.E