Path: utzoo!utgpu!watmath!clyde!att!rutgers!apple!vsi1!wyse!mips!sultra!dtynan
From: dtynan@sultra.UUCP (Der Tynan)
Newsgroups: comp.unix.microport
Subject: Re: Microport V/AT Printer Spooler non-Problem
Summary: "Centronics" just describes the interface.
Keywords: Microport lp hangs non-bug
Message-ID: <2704@sultra.UUCP>
Date: 5 Dec 88 23:31:50 GMT
References: <1559@ssc.UUCP>
Organization: Tynan Computers, Sunnyvale, CA
Lines: 25

In article <1559@ssc.UUCP>, fyl@ssc.UUCP (Phil Hughes) writes:
> 
> About 1 hour later they called back.  Things had stopped working.  An
> lpstat showed the old "printer spooler bug" - idle printer but files in
> the queue.  This is only one data point but it sounds to me like there is
> a difference between Centronics and Centronics compatible.
>
> Phil Hughes, SSC, Inc. P.O. Box 55549, Seattle, WA 98155  (206)FOR-UNIX

One thing I would check for, is the printer buffering.  A "Centronics"
interface is just that.  An interface.  A lot of older printers don't have
any kind of buffering, which means that you have to feed it data at the
print rate.  This can result in an interrupt-per-character type arrangement,
which can kill even the best operating system :-(  On newer printers, once
you get the interrupt, you can handshake in a lot of chars at once, meaning
that the latency is a lot less.  It seems to me, that the driver/printer
interface is getting confused.  This could be a result of heavy interaction.
Note however, that I don't use Microport UN*X, so the above is nothing more
than idle speculation, given the information posted.  Hope it helps...
						- Der
-- 
	dtynan@zorba.Tynan.COM  (Dermot Tynan @ Tynan Computers)
	{apple,mips,pyramid,uunet}!Tynan.COM!dtynan

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