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From: Soeren Schmidt <sos@spider.deepcore.dk>
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To: Buckie <freebsd1@centrum.cz>
Date: Thu, 31 Jul 2003 14:19:21 +0200 (CEST)
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cc: freebsd-hackers@freebsd.org
Subject: Re: Ultra ATA card doesn't seem to provide Ultra speeds.
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It seems Buckie wrote:
> I ran a dd:
> dd if=/dev/ad1 of=/dev/zero ibs=8192
> ...and cancelled it after some amount of time:
> 2321+0 records in
> 37136+0 records out
> 19013632 bytes transferred in 27.876118 secs (682076 bytes/sec)
> 
> I don't use static2 ata device numbering hence Maxtor is assigned ad1,
> but it would be ad4 if things were static.
> 
> Experiemnting with ibs value I can get speeds of up to 16MB per
> second. But no more.

OH, you need to output to /dev/null NOT /dev/zero :)

besides that, all looks OK, but you need a fairly large bs to se improvments
on this (relatively slow) machine, try a bs of 1m and see if that
helps, if not there is something slowing down your system..


-Søren