Re: advanced dualboot linux+win with grub

From: CBFalconer (cbfalconer_at_yahoo.com)
Date: 08/02/05 

Date: Tue, 02 Aug 2005 13:25:03 GMT

Timothy Murphy wrote:
> CBFalconer wrote:
>
>> I don't know about grub, but I imagine the fundamentals are similar
>> to lilo, in that the initial default and options are written into
>> the MBR.
>
> That isn't right.
> The default is written in /etc/grub.conf ,
> and can be changed without re-writing the MBR.
>
>> After all, when the machine boots that is all the
>> information available. So any such flipping of the default would
>> involve rewriting the MBR. This would mean that any fault could
>> easily write an invalid MBR and result in an unbootable machine.
>
> You are wrong.
>
> Regarding the OP's query, I have seen postings explaining
> how to make changes similar to the one he/she wants.
> It could be done by getting Linux to re-write /etc/grub.conf
> when you logout.
> But there is probably a better way.

That would require that the boot loader in the MBR know how to read
and interpret the grub.conf file without the benefit of any
filesystem in place. I can conceive of hairy ways to do that
involving the MBR knowing absolute disk addresses of things, but I
can hardly imagine that being robust. It would also limit the
filesystems ability to relocate grub.conf (or some other module) in
normal operation. 

-- 
"If you want to post a followup via groups.google.com, don't use
 the broken "Reply" link at the bottom of the article.  Click on 
 "show options" at the top of the article, then click on the 
 "Reply" at the bottom of the article headers." - Keith Thompson