Re: [PATCH] Skip partitions during OS probing

[Axel Kellermann <axel.kellermann@gmx.de>]

On 07/11/2011 10:21 PM, Phillip Susi wrote:
> Fixing the underlying problem of detecting and ignoring the Win7 system
> partition would render the patch moot.  If it does really still cover a
> use-case to be able to manually specify partitions to ignore, it needs
> to be done with UUIDs or something else more stable.
Just to tie up that loose end, I had a look at the way update-grub
determines the presence of a bootable Win7 partition. Turns out it
utilizes the os-prober package, which basically uses a four step process
to check for a Win7 system:

1. check for presence of file /bootmgr
2. check for presence of directory /boot/
3. check for presence of file /boot/bcd
4. grep OS version string from file /boot/bcd

If all four steps succeed, the partition is classified as bootable and
update-grub writes a boot meny entry.

The Win7 system partition on my machine passes all the checks os-prober
does, but actually booting from that partition fails with an error
message. To solve this, os-prober would have to include some kind of
sanity check whether the bootloader configuration on the examined
partition is set up correctly and really boots the system. I'm not sure
if that is feasible and/or possible at all, and one could also argue
that it's up to the user to fix the faulty boot setup on the partition
and not blame grub/os-prober for detecting a messed up bootloader. :)

Thoughts?

BTW, I still think the patch covers a use-case and its functionality
could be handy.


Thanks,

Axel