Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!bcm!shell!nuchat!steve
From: steve@nuchat.UUCP (Steve Nuchia)
Newsgroups: comp.unix.wizards
Subject: Re: System performance
Keywords: sluggish, slow, non-existent
Message-ID: <13436@nuchat.UUCP>
Date: 11 Aug 89 14:40:34 GMT
References: <932@lakesys.UUCP>
Reply-To: steve@nuchat.UUCP (Steve Nuchia)
Distribution: comp.unix.wizards,comp.unix.xenix
Organization: Houston Public Access
Lines: 15

In article <932@lakesys.UUCP> davef@lakesys.UUCP (Dave Fenske) writes:
>When there is a disk intensive program running, if there is a lot of sequential
>I-O, the performance level of SCO Xenix seems to drop to nill (NULL).  This

I have observed a similar phenomenon on my Bell Tech 386 3.0 system.
In particular, I can run
	dd if=/dev/dsk/0s3 of=/dev/null bs=16k
for instance and absolutely nothing else gets serviced on that disk
until I kill it.  I interpret this as an effect of the elevator
algorithm.  It would have to be modified with some kind of fairness
provision to prevent this behaviour.
-- 
Steve Nuchia	      South Coast Computing Services
uunet!nuchat!steve    POB 890952  Houston, Texas  77289
(713) 964 2462	      Consultation & Systems, Support for PD Software.