From: "H. Peter Anvin" <hpa@zytor.com>
To: Doug Ledford <dledford@redhat.com>
Cc: Janek Kozicki <janek_listy@wp.pl>, linux-raid@vger.kernel.org
Subject: Re: switching root fs '/' to boot from RAID1 with grub
Date: Thu, 01 Nov 2007 11:57:24 -0700 [thread overview]
Message-ID: <472A2194.9070408@zytor.com> (raw)
In-Reply-To: <1193941858.10336.659.camel@firewall.xsintricity.com>
Doug Ledford wrote:
>
> Correct, and that's what you want. The alternative is that if the BIOS
> can see the first disk but it's broken and can't be used, and if you
> have the boot sector on the second disk set to read from BIOS disk 0x81
> because you ASSuMEd the first disk would be broken but still present in
> the BIOS tables, then your machine won't boot unless that first dead but
> preset disk is present. If you remove the disk entirely, thereby
> bumping disk 0x81 to 0x80, then you are screwed. If you have any drive
> failure that prevents the first disk from being recognized (blown fuse,
> blown electronics, etc), you are screwed until you get a new disk to
> replace it.
>
What you want is for it to use the drive number that BIOS passes into it
(register DL), not a hard-coded number. That was my (only) point --
you're obviously right that hard-coding a number to 0x81 would be worse
than useless.
-hpa
next prev parent reply other threads:[~2007-11-01 18:57 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-30 20:07 switching root fs '/' to boot from RAID1 with grub Janek Kozicki
2007-10-30 20:37 ` Janek Kozicki
2007-10-30 22:01 ` Doug Ledford
2007-10-31 15:01 ` Janek Kozicki
2007-10-31 17:38 ` Doug Ledford
2007-10-31 20:12 ` xosview + RAID (was: switching root fs '/'...) Janek Kozicki
2007-10-31 20:47 ` xosview + RAID David Greaves
2007-11-01 17:31 ` switching root fs '/' to boot from RAID1 with grub H. Peter Anvin
2007-11-01 18:30 ` Doug Ledford
2007-11-01 18:57 ` H. Peter Anvin [this message]
2007-11-02 15:55 ` Doug Ledford
2007-11-01 19:04 ` Janek Kozicki
2007-11-01 19:20 ` Doug Ledford
2007-11-02 16:36 ` berk walker
2007-11-04 3:18 ` Bill Davidsen
2007-11-04 3:44 ` H. Peter Anvin
2007-11-04 4:28 ` Bill Davidsen
2007-11-04 18:02 ` H. Peter Anvin
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