Re: partition table read incorrectly

Re: partition table read incorrectly

[Andries.Brouwer]

>> Maybe there is still "0xaa55" on the disk at 0x1fe and the kernel
>> thinks it is a DOS partition?

> Note that that is true for *ANY* partition scheme which is bootable,
> since this is a requirement of the boot firmware interface, rather of
> any particular partitioning scheme...

You mean on i386 hardware? With the most common BIOS versions?

Re: partition table read incorrectly

[Charles Marslett]

Andries.Brouwer@cwi.nl wrote:
> 
> >> Maybe there is still "0xaa55" on the disk at 0x1fe and the kernel
> >> thinks it is a DOS partition?
> 
> > Note that that is true for *ANY* partition scheme which is bootable,
> > since this is a requirement of the boot firmware interface, rather of
> > any particular partitioning scheme...
> 
> You mean on i386 hardware? With the most common BIOS versions?

I think it applies to almost all boot firmware -- the Atari 68000 hard
disk format used it, all the x86 firmware I am familiar with uses it, and
I think Apple uses it in all it's Mac incarnations.  That's pretty wide
coverage (I know nothing about Sun or other workstation formats).

If the 0xAA55 marker is not present, the standard interpretation is that
the disk is not partitioned, and the disk may still boot, but you may
just be lucky it works if it really is partitioned.

Or have I missed something (I'm not all that familiar with non-x86 hardware
so I could be missing something big -- and I'd like to know that)?

--Charles

partition table read incorrectly

[Wichert Akkerman]

I seem to run into a weird problem. LVM refused to work properly,
after a "vgscan" command "vgchange -a y" would still complain
that things weren't consistent and I got a messages about an
I/O error on 08:11.

Interestingly my sdb does not have any partitions since it's one
big PV, and fdisk agrees with me on that. However the kernel
seems to thing I do have a partition there and as a result LVM
seems to get somewhat confused.

This happens with both 2.4.9-ac17 and 2.4.10-ac3. If anyone has
any ideas on how to go about fixing this don't hestitate to ask
me for more details.

Wichert.

-- 
  _________________________________________________________________
 /       Nothing is fool-proof to a sufficiently talented fool     \
| wichert@wiggy.net                   http://www.liacs.nl/~wichert/ |
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Re: partition table read incorrectly

[Alan Cox]

> I seem to run into a weird problem. LVM refused to work properly,
> after a "vgscan" command "vgchange -a y" would still complain
> that things weren't consistent and I got a messages about an
> I/O error on 08:11.

Does it complain about wrong block sizes ?

> Interestingly my sdb does not have any partitions since it's one
> big PV, and fdisk agrees with me on that. However the kernel
> seems to thing I do have a partition there and as a result LVM
> seems to get somewhat confused.

The partition code will look for tables. That bit is fine

The exact error would be good too

Re: partition table read incorrectly

[Wichert Akkerman]

Previously Alan Cox wrote:
> Does it complain about wrong block sizes ?

No
 
> The partition code will look for tables. That bit is fine

If that bit is fine then how can it differ in opinion from fdisk?

> The exact error would be good too

 I/O error: dev 08:11, sector 0

Wichert.

-- 
  _________________________________________________________________
 /       Nothing is fool-proof to a sufficiently talented fool     \
| wichert@wiggy.net                   http://www.liacs.nl/~wichert/ |
| 1024D/2FA3BC2D 576E 100B 518D 2F16 36B0  2805 3CB8 9250 2FA3 BC2D |

Re: partition table read incorrectly

[Andreas Dilger]

On Oct 02, 2001  22:00 +0200, Wichert Akkerman wrote:
> Previously Alan Cox wrote:
> > Does it complain about wrong block sizes ?
> 
> No
>  
> > The partition code will look for tables. That bit is fine
> 
> If that bit is fine then how can it differ in opinion from fdisk?

What does the first 512 bytes of the disk show (od -Ax -tx1 /dev/)?
Maybe there is still "0xaa55" on the disk at 0x1fe and the kernel
thinks it is a DOS partition?

> > The exact error would be good too
> 
>  I/O error: dev 08:11, sector 0

Hmm, this is sda11, so you would need both a primary and extended
partition table to get that.  What does /proc/partitions show?

Cheers, Andreas
--
Andreas Dilger  \ "If a man ate a pound of pasta and a pound of antipasto,
                 \  would they cancel out, leaving him still hungry?"
http://www-mddsp.enel.ucalgary.ca/People/adilger/               -- Dogbert

Re: partition table read incorrectly

[H. Peter Anvin]

Followup to:  <20011002150820.N8954@turbolinux.com>
By author:    Andreas Dilger <adilger@turbolabs.com>
In newsgroup: linux.dev.kernel
> > 
> > If that bit is fine then how can it differ in opinion from fdisk?
> 
> What does the first 512 bytes of the disk show (od -Ax -tx1 /dev/)?
> Maybe there is still "0xaa55" on the disk at 0x1fe and the kernel
> thinks it is a DOS partition?
> 

Note that that is true for *ANY* partition scheme which is bootable,
since this is a requirement of the boot firmware interface, rather of
any particular partitioning scheme...

	-hpa
-- 
<hpa@transmeta.com> at work, <hpa@zytor.com> in private!
"Unix gives you enough rope to shoot yourself in the foot."
http://www.zytor.com/~hpa/puzzle.txt	<amsp@zytor.com>

Re: partition table read incorrectly

[Guest section DW]

On Tue, Oct 02, 2001 at 03:08:20PM -0600, Andreas Dilger wrote:

> >  I/O error: dev 08:11, sector 0
> 
> Hmm, this is sda11

No. These messages give hex values.

Re: partition table read incorrectly

[Alan Cox]

> If that bit is fine then how can it differ in opinion from fdisk?
> 
> > The exact error would be good too
> 
>  I/O error: dev 08:11, sector 0

Nothing before or after it ?

Re: partition table read incorrectly

[Wichert Akkerman]

Previously Alan Cox wrote:
> Nothing before or after it ?

Nothing at all.

Wichert.

-- 
  _________________________________________________________________
 /       Nothing is fool-proof to a sufficiently talented fool     \
| wichert@wiggy.net                   http://www.liacs.nl/~wichert/ |
| 1024D/2FA3BC2D 576E 100B 518D 2F16 36B0  2805 3CB8 9250 2FA3 BC2D |