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From: mmm@iconsys.UUCP
Newsgroups: comp.unix.wizards
Subject: Re: inexplicable slowness
Message-ID: <145@iconsys.UUCP>
Date: Wed, 4-Feb-87 23:40:00 EST
Article-I.D.: iconsys.145
Posted: Wed Feb  4 23:40:00 1987
Date-Received: Sat, 7-Feb-87 14:40:43 EST
References: <146@dcl-csvax.comp.lancs.ac.uk> <4760004@hpirs.HP>
Lines: 21
Summary: check your serial ports


Oftentimes, I have seen serial ports that were not terminated
properly (i.e. when the terminal is turned off) have problems
with line ringing.  What happens is that a character is generated
on the line, echoed by the host, then reflected back to the
host again, ad infinitum.  This can really affect performance, 
especially if you have more than one line going.  

Doing an iostat or equivalent will display the amount of character
traffic, and if this is high when there is no good reason for it,
line ringing could be your problem.

One solution is to always log out before turning off a terminal 
(a good idea anyway), because getty will not echo forever.  Another 
solution might be to check your hardware and make sure your lines are 
terminated properly.
-- 

	Mark Muhlestein @ Icon International Inc.

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