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Date:      Mon, 3 Aug 1998 19:27:49 +0000 (GMT)
From:      Terry Lambert <tlambert@primenet.com>
To:        bde@zeta.org.au (Bruce Evans)
Cc:        current@FreeBSD.ORG, rock@cs.uni-sb.de
Subject:   Re: IO performance (UFS read clustering), bad ZIP drive performance
Message-ID:  <199808031927.MAA01657@usr07.primenet.com>
In-Reply-To: <199808030726.RAA16337@godzilla.zeta.org.au> from "Bruce Evans" at Aug 3, 98 05:26:02 pm

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> >I get unacceptable performance from my SCSI ZIP drive (compared to other
> >operating systems). While UFS writing is OK (up to the capabilities of the
> >drive: 600-1000 kB/s), everything else (UFS read, MSDOSFS r/w, mtools)
> >is extremely slow (down to 80 kB/s).
> 
> ufs clustered reads have been broken (except on wd drives) since rev.1.18
> (1998/01/24) of ufs_bmap.c.  SCSI ZIPs have a huge command overhead
> (20 msec here on an ncr 53c810) and don't seem to support tags, so
> performance without clustering is poor.
> 
> Fix:

Is there a particula reason you are posting this to -current instead of
to the CVS tree?


					Terry Lambert
					terry@lambert.org
---
Any opinions in this posting are my own and not those of my present
or previous employers.

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