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GRUB

Posted: Fri Mar 08, 2002 12:00 am
by Alexei
GRUB loads kernel, enters protected mode
and jums to my kernel entry point, right?
Where is located GDT, IDT?

RE:GRUB

Posted: Sat Mar 09, 2002 12:00 am
by J. Weeks
>On 2002-03-08 02:06:47, Alexei wrote:
>GRUB loads kernel, enters protected mode
>and jums to my kernel entry point, right?
>Where is located GDT, IDT?

Uhm... I don't think so... have you read the docs?
It looks to me like it simply loads your kernel
and jumps to it, loading in any support modules
if need be (such as in a VSTa or MACH microkernel).

I know GRUB is intended for 32-bit pmode OSs, but
it'll also boot DOS, right? So, I doubt it'll
enter pmode (seeing as though DOS can't run
in pmode).

Anybody know for sure?

All this stuff's gotta be in the multiboot
standard, and the GRUB docs, though.
http://www.gnu.org/software/grub/

Jeff

RE:GRUB

Posted: Sat Mar 09, 2002 12:00 am
by Chris Giese
>On 2002-03-08 02:06:47, Alexei wrote:
>GRUB loads kernel, enters protected mode
>and jums to my kernel entry point, right?

Right.

>Where is located GDT, IDT?

The location and layout of the GRUB GDT is undefined. You should create your own.

GRUB does not define an IDT. You must create your own.

AFAIK, real-mode is supported only for chain-loaded bootsectors.
This is how GRUB boots DOS.