[LinuxBIOS] Using GRUB as a payload

Al Boldi a1426z at gawab.com
Mon Sep 25 06:52:37 CEST 2006

Stefan Reinauer wrote:
> * Al Boldi <a1426z at gawab.com> [060924 21:14]:
> > So maybe leave the bootloader chainloaded as a separate module from the
> > block-driver.
> In theory possible but fragile. Of course you can load any number of
> intermediary loaders from disk.
> > > No, "a simple MBR chainloader" is not all that is needed. The code
> > > that you will find in an MBR will do bios callbacks, and you need to
> > > answer those, or you will jump to nirvana.
> >
> > Ok, that's why we need a block-driver to chainload the MBR.
> No, the block driver is there. It is Grub/LILO itself that calls 16bit
> bios code. And LinuxBIOS doesnt have 16bit bios code.
> This has nothing to do with a block driver.

LinuxBIOS is 32bit.  AwardBIOS is 16bit.  Grub/LILO is 16bit.
ADLO is a 32bit/16bit BIOS call translation layer needed for 16bit BIOS calls 
to succeed on a 32bit LinuxBIOS.

ADLO should not be necessary on a 32bit-BIOS with 32bit bootloader bioscalls, 
nor should it be necessary on a 16bit-BIOS with 16bit Grub/Lilo bioscalls.


> > > What is your requirement? Loading Windows?
> >
> > Loading Linux, on an i440bx with a brain-dead AwardBIOS that can't boot
> > USB, nor can it boot disks >32GB.
> >
> >
> > Filo does the trick, but has its issues wrt
> > APM and its inability to remember boot commands like LiLo can.
> How does APM come into play here?!?

When loading vmlinuz using Filo, on an i440bx with a 16bit AwardBIOS, APM 
mysteriously disappears.  I am hoping by chainloading Grub/Lilo to load 
vmlinuz properly for APM to survive.

> So one requirement is: - remembering boot commands.
> So you want to choose which OS to boot on the next reset?
> This is a 3 liner patch to FILO..

Great feature!

> > Would chainloading LiLo be possible?
> No, as I mentioned. Its a 16bit bootloader that requires a 16bit bios.

AwardBIOS is a 16bit bios.  No?

Thanks for enduring my questions!


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