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From: rcb@RTI-SEL.UUCP (Random)
Newsgroups: mod.computers.vax
Subject: Re: User-modified print symbionts.
Message-ID: <8602261404.AA12266@rti-sel>
Date: Wed, 26-Feb-86 09:04:20 EST
Article-I.D.: rti-sel.8602261404.AA12266
Posted: Wed Feb 26 09:04:20 1986
Date-Received: Sun, 2-Mar-86 04:25:23 EST
References: <8602250741.AA05066@csvax.caltech.edu>
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Organization: Research Triangle Institute, RTP, NC
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I have seen your problem about the print symbionts. I wrote a symbiont to
talk to an Imagen laser printer that talks a WEIRD packet protocol. The printer
is also shared by many computers on our terminal switch, so I had to release
the printer when I was done so that other computers could have it.

The solution I found was a simple timer. In the output routine, I would cancel
the timer and restart it just before returning. If the timer ever timed out
(about 10 seconds was sufficient), I interpreted this as end of job and
dropped the connection. If more than one job was in the queue, these would be
sent without any pause but would have a packet sent with psm$k_start_task
(A task being a full print job (all files)). This seems to work fairly well.

Also, Any print/passall command will cause the symbiont to loop forever.
However, if you can create or munge the file to be printed with /passall into
a file with carriage control=none, It will have the same effect as /passall.


					Random (Randy Buckland)
					Research Triangle Institute
					...!mcnc!rti-sel!rcb