Re: Default Grub legacy menu.lst to Grub2 grub.cfg

[Andrey Borzenkov]

В Tue, 8 Jan 2013 11:20:07 -0700
Chris Murphy <address@hidden> пишет:

> 
> On Jan 8, 2013, at 10:26 AM, Tom Oakes <address@hidden> wrote:
> 
> > My Disk does have a MBR with Grub 1.98 installed to access the /boot/grub 
> > directory of the ubuntu system installed in /dev/sdb5, which is in the 
> > extended partition /dev/sdb3. The ubuntu boots with no problem from the 
> > installed Grub2 system.
> 
> GRUB 1.98 is positively ancient, it's almost three years old. And that was a 
> development version for GRUB2. The final stable shipping release is 2.00. You 
> really do need to upgrade, there have been many, many changes. I suggest 
> building it from source, or maybe finding a newer version from Ubuntu's 
> repositories. They should have one by now.
> 
> > 
> > I have two basic questions:
> > 1. Is correct that it necessary for the Grub2 MBR to be access Grub files 
> > installed in a separate partition in order for it to boot freeBSD?
> 
> No.
> 

Not quite. GRUB2 has modular design. It consists of many small drivers
(modules), each for a single feature. The part, that is embedded (in
post-MBR gap) usually contains the minimal number of modules which are
exactly enough to access another file system, where all other modules
are located.

So to have full featured GRUB2 answer is - yes, it needs access to
GRUB2 files in another partition.

It is possible to build monolithic GRUB2 that has everything, but then
it won't fit in post-MBR gap anymore.

> > 
> > 2. If it is necessary, can it be a partition in an extended partition?
> 
> No, because extended partitions mean you're using MBR. And for MBR there is 
> no such thing as a partition for GRUB. That's only for GPT. If you're using 
> MBR, then GRUB belongs in the MBR gap between LBA 0 and LBA 2048.
> 

You mix "partition to embed GRUB2" and "partition to store GRUB2
files". On GPT with bios_grub partition it contains image with enough
drivers to access another partition with filesystem that in turn
contains all other GRUB2 files.

To reply to original question - it can be any partition as long as this
partition has filesystem that is recognized by GRUB2.