Subject: Re: terabyte array and negative cylinders
From: David Laight <firstname.lastname@example.org>
Date: 07/03/2003 10:00:11
On Thu, Jul 03, 2003 at 10:44:34AM +0200, Ignatios Souvatzis wrote:
> On Wed, Jul 02, 2003 at 05:07:22PM +0100, David Laight wrote:
> > > I haven't really looked at the code yet, but just thought I'd toss this
> > > out & see what other people thought--I haven't seen any mention of terabyte
> > > arrays & NetBSD on the net anywhere.
> > There are a lot (and I mean LOT) of places where the disk sector number
> > is held in an int. Much of the kernel was changed to use daddr_t (64bit)
> > but that doesn't help much since all the disklabel/mbr handling only
> > had 32 bit fields.
> > Clearly the 32bit values could be unsigned, but that only gives a factor
> > of 2 - and if you can build a 1TB disk, a 2TB one shouldn't be hard!
> Note that negative values of 32 bit disk numbers are used as a special flag
> in some places in the file system code. On-disk.
But wouldn't they be 'fragment' numbers?
Limiting a UFS1 filesystem to 2^31 fragments - easily > 2^32 sectors.
David Laight: email@example.com