From owner-freebsd-scsi  Sun Oct  5 04:51:53 1997
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Date: Sun, 5 Oct 1997 13:48:40 +0200
From: j@uriah.heep.sax.de (J Wunsch)
To: freebsd-scsi@FreeBSD.ORG
Cc: phk@FreeBSD.ORG (Poul-Henning Kamp), davidg@FreeBSD.ORG (David Greenman)
Subject: Re: New SCSI Framework Patches Available
References: <19971005115559.AS58851@uriah.heep.sax.de> <199710051052.FAA00587@dyson.iquest.net>
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Reply-To: joerg_wunsch@uriah.heep.sax.de (Joerg Wunsch)
In-Reply-To: <199710051052.FAA00587@dyson.iquest.net>; from John S. Dyson on Oct 5, 1997 05:52:50 -0500
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As John S. Dyson wrote:

(Me, about supporting arbitrary block sizes.)

> > I would prefer a transition from b_blkno to b_offset, thereby
> > eliminating all the ``shift right here, shift back left there'' mess
> > completely.

> SCSI isn't probably the best place to discuss the eventual transition
> from b_blkno to b_offset,

Well, it has less babble than -hackers, and seems to have all the
relevant people on it anyway. :-)

> but I don't think that it will cause us very much inefficiency to
> move to the offset representation.  My opinion (guess) is due to all
> of the conversions that we are already doing being costly.

Sounds reasonable.

> The cost is compounded by the necessity for us to do alot of the
> calculations in 64bits anyway.  If we think that this should be a
> 3.0 thing, let's make the decision ASAP,

I'm willing to sacrifice my scratch machine for testing.  It's
probably beyond my understanding to resolve the various abuses of
b_blkno however.  (The transition itself could probably be done in a
rather mechanic way, only these abuses need to be resolved manually,
and replaced by better methods for providing arbitrary `cookies'.)

> and make sure that DG, BDE, and PHK get involved in the
> discussions.

Bruce is listening to -scsi.  I'm Cc'ing David and Poul, remove your
names again if you are already on the list.

-- 
cheers, J"org

joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE
Never trust an operating system you don't have sources for. ;-)