Re: How to de-Grub?
On Thu, 2004-07-22 at 13:35, Robert William Hutton wrote:
> Stephen Cradock wrote:
> >
> I'd recommend that you install LILO using the first woody CD. LILO, unlike
> GRUB, installs itself exclusively in the MBR, so you don't need some other
> partition for the stage 2 loader which GRUB requires.
Are you sure? The MBR is only 512 bytes. I'm pretty sure that LILO gets
the MBR to point to the "real" LILO data residing inside a linux
filesystem, just like Grub does. You don't get much code inside 512
bytes...
I believe the MBR simply holds a list of block offsets within the disk,
and enough code to load the data in those disk blocks into memory and
jump to them. The loaded data normally resides as real files in a
filesystem (which had better not try to move them, eg via
"defragmenting" the disk).
The difference (AFAIK) is that Grub has the option of getting the MBR to
"raw load" a simple "stage 1.5" app that knows about filesystems, and
loads the real bootloader "stage 2" using proper filesystem semantics.
Lilo instead essentially puts all its logic in the "stage1.5" file.
Quite what benefit Grub gets from the separation of stage1.5 vs stage2 I
don't know. And I see that "grub2" is going to do away with the
"stage1.5" concept.
Potentially, I guess, the LILO bootloader (and grub stage 1.5) can
reside in a disk partition that has never been formatted as any kind of
filesystem, because the data is fetched using raw disk block addresses.
But who ever does that? Maybe it's useful for embedded systems..
Cheers,
Simon
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