From owner-freebsd-scsi  Mon Oct  2 19:53:11 2000
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From: Terry Lambert <tlambert@primenet.com>
Message-Id: <200010030252.TAA01796@usr06.primenet.com>
Subject: Re: Partitioning (was: ccd with other filesystems)
To: grog@lemis.com (Greg Lehey)
Date: Tue, 3 Oct 2000 02:52:51 +0000 (GMT)
Cc: tlambert@primenet.com (Terry Lambert), freebsd-fs@FreeBSD.ORG,
	freebsd-scsi@FreeBSD.ORG
In-Reply-To: <20001003090846.F372@wantadilla.lemis.com> from "Greg Lehey" at Oct 03, 2000 09:08:46 AM
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> > The PReP specification makes it crystal clear how you can
> > support up to 2^32 sectors with the DOS partition table
> > mechanism.  It's perhaps the best documentation I've ever
> > seen for the DOS partition table, and the 32 bit sector
> > field.  I'd have bought the thing for that documentation
> > alone, had I known it was there when I needed it.
> 
> Why do we need it?

Compatability?  Interoperability?  Booting disks on AlphaBIOS,
Motorolla PowerStack machines, etc.?  To avoid yet another
gratuitous difference from the rest of the world?


> > PS: That's 112 TB, in LBA mode.
> 
> I make 1 TB for signed sector numbers, which is what we already have.
> How do you get 112 TB out of 512*2**31?

Sorry, 2TB (it's unsigned).

2^32 * 512 = 2.233383e+11

I guess I clicked again when I shouldn't have in the calculator;
my bad.  I should have done it in my head, instead; it's easy
to say "4 billion over 2 times 1000".


					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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