Re: multiboot2: make multiboot header optional

[Yoshinori K. Okuji]

On Wednesday 15 November 2006 19:42, Hollis Blanchard wrote:
> > If the operating system kernel is stupid enough to require as special
> > video mode the user should be aware of that and setup the bootloader
> > so that it is in that mode before the kernel is started.
>
> The only information in the multiboot header is a) the load addresses
> for a.out and "other" formats, and b) the VGA info.
>
> We could certainly drop the VGA info.

No. The problem is that a kernel cannot initialize VESA in protected mode in 
some BIOSes. If you need more info, please dig into the archive of bug-grub.

> I don't think it would be a big deal to drop a.out as well; I don't know
> of any modern OS that uses these, and anyways kernel builds are special.
> However (and I don't know how reasonable this is), Mac OS X's toolchain
> will build only Mach-O binaries, so one would be unable to build a
> kernel that GRUB could load. We could require a Mach-O loader in that
> case, but I will admit that the "a.out hack" multiboot header fields
> simplify this problem.

Never drop the a.out kludge. This flexibility is one of the advantages in 
Multiboot. Note that GRUB itself uses this feature.

Okuji