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Date: Thu, 20 Feb 1997 15:37:15 +1100
From: Bruce Evans <bde@zeta.org.au>
Message-Id: <199702200437.PAA19813@godzilla.zeta.org.au>
To: bde@zeta.org.au, msmith@atrad.adelaide.edu.au
Subject: Re: _big_ IDE disks?
Cc: hardware@freebsd.org, se@freebsd.org
Sender: owner-hardware@freebsd.org
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>> I checked the specs for it.  It really can do > 8MB/s except
>> possibly on the inner tracks.
>
>Yup, this was a basic criteria for it being used instead of a SCSI
>disk; by the time you compensate for the extra CPU overhead, I figured
>that it would make a reasonable alternative to a ~3M/sec SCSI disk
>(which was not available 8( )

The DORS-32160 is 5-6MB/sec, but you only nead a FireballTM to compete
with that on transfer speed :-).

>> from the buffer cache.  If the CPU is a P5/166, then i586-optimized
>> copyout is apparently not being used.  I think the overhead would be

>How do I go about ascertaining this?  npx0 is enabled, and the kernel
>was build with I586_CPU defined (obviously). The kernel it's running
>is built with npx.c v 1.31.2.5.

I can't think of a better way than using `cvs log'.  It was reenabled
in npx.c 1.31.2.6.  Other ways: run a debugger and look at the vectors.
Run `dd if=/dev/zero of=/dev/null bs=1m count=1000' and complain if
the throughtput is much lower than 120MB/sec.

Bruce