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From: tim@cit-vax.Caltech.Edu (Timothy L. Kay)
Newsgroups: comp.unix.i386
Subject: Future Domain 881: How fast?
Message-ID: <15527@cit-vax.Caltech.Edu>
Date: 6 Jul 90 23:14:57 GMT
Reply-To: tim@cit-vax.UUCP (Timothy L. Kay)
Distribution: usa
Organization: California Institute of Technology
Lines: 24

I have seen quite a discussion about performance tuning the Adaptec
controller.  I have a Future Domain 881, and I am curious just how
fast I should expect it to be.  I did

	dd if=/unix of=/dev/null bs=32k

and clocked about 170 KB/s.  I did a

	dd if=/dev/rdsk/0p0 of=/dev/null bs=32k count=100

and clocked about 360 KB/s.  First of all, are these all I can
expect?  I understand that the 881 is a slower controller, and
I have only a 386/20 anyway.

Secondly, why do I get timings like

	0.1u 9.1s 0:07 130%

in which I get more than 100% of the machine?  Is it that
the accounting is messed up because interrupts are being
turned off for a non-trivial amount of time or something
like that?

Tim