Re: In a multiboot context (2 Ubuntu and 2 Windows OSes), Grub shows a very surprising behavior. Is this a bug ?

[Jordan Uggla]

First, please don't send html email to help-grub (or to most other
technical mailing lists). It often makes it more difficult to read and
in this case has messed with the proper indentation of replied
messages with '>'.

On Thu, Apr 5, 2012 at 10:25 AM, Arbiel Perlacremaz
<address@hidden> wrote:
> Grub sits on the MBR of each drive and, as long as we have been able to
> understand, each Grub instance points to a unique grub.cfg, which sits on
> drive 1.

This last sentence is unclear, but what the boot info script output
shows is that each drive has grub installed to its mbr, and every
drive's grub is configured to read a grub.cfg contained on their own
drive, i.e. every time you change which drive is booted from the BIOS
you are changing which grub.cfg is read.

> Here is the bootinfo report

You'll notice that there are a total of 5 menu entries relating to
Windows from the various grub.cfg files. From sdc1's
/boot/grub/grub.cfg we have:

menuentry "Windows 7 (loader) (on /dev/sdb1)" --class windows --class os {
    insmod part_msdos
    insmod ntfs
    set root='(hd1,msdos1)'
    search --no-floppy --fs-uuid --set=root 439C8E7F4DCFF3BB
    chainloader +1
}
menuentry "Windows 8 (loader) (on /dev/sda5)" --class windows --class os {
    insmod part_msdos
    insmod ntfs
    set root='(hd0,msdos5)'
    search --no-floppy --fs-uuid --set=root CE80A4F080A4E067
    chainloader +2
}


>From sdc6's /boot/grub/grub.cfg we have:

menuentry "Windows 7 (loader) (on /dev/sda1)" --class windows --class os {
    savedefault
    insmod part_msdos
    insmod ntfs
    set root='(hd0,msdos1)'
    search --no-floppy --fs-uuid --set=root F64836B14836710B
    chainloader +1
}

menuentry "Microsoft Windows Seven (sda1)" {
        set root=(hd1,1)
        chainloader +1
}
menuentry "Microsoft Windows Seven (sdb1)" {
        set root=(hd2,1)
        chainloader +1
}


Every one of these is different, pointing to a different partition.
(The last two menu entries are manually added ones which don't search
by UUID, making them unreliable)

My guess is that the user is simply confusing menu entries which have
very similar titles but which are not in fact the same.

-- 
Jordan Uggla (Jordan_U on irc.freenode.net)