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

[Arbiel Perlacremaz]

Hi

This call for help is related to an issue raised on the Ubuntu.fr forum. Even if you don't understand french, you will find there BootInfo reports, menuentry codes, ...  I can help translate any additionnal information you may fell necessary to understand.

The situation is the following :
three disk drives
first drive : two Ubuntu 11.10 et 12.04
second drive : Windows 7
third drive : Windows 8.

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.

4 menues entries (discarting the recovery and memory testing entries)
Ubuntu 11.10
Ubuntu 12.04
Windows 7
WIndows 8.

Windows 7 menuentry boots Windows 8.

This may be a Windows issue, however tests run by the user show a very surprising Grub's behavior.

When the BIOS points to the second drive, the selection of  the Windows 7 menuentry boots Windows 7. This is quite surprising as Grub sits on the MBR of this drive and uses the same grub.cfg file as the Grub which sits on drive 1. The only difference in the two runs seems to be the way grub names the drives. But even this does not explain the behavioral difference, as the "set root=(hdx,msdosy)" are followed by a "search --set=root" instruction before invoking the "chainloader" command.

By the way, what is the purpose of the "set root=" commands ? They seem to me to be quite useless, unless ${root} is taken as a default value for the --hint option of the search command. And in that case, why not code the --hint option into the search command.

Any explanation will be welcome.

Arbiel