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GRUB Problem... again!
Posted: Thu Feb 20, 2003 9:40 pm
by Mastermind
I'm trying to switch to using GRUB to boot up my OS. I've got it installed on my floppy disk. I cannot load my OS from it. I figured that this may be because my OS is not "multiboot compliant." What is "multiboot compliance" and how can I make my OS compliant? Is there a solution?
The OS runs fine from my current loader, so it cannot be a programming error...
??? ??? ??? ???
Re:GRUB Problem... again!
Posted: Thu Feb 20, 2003 10:05 pm
by Parabola1
Just did this today for myself.
Here are a few links to help you.
The big multiboot specification:
http://www.mcc.ac.uk/grub/multiboot_toc.html
The "quickstart" guide to grub and multiboot:
http://osdev.neopages.net/tutorials/grub.php
That last link was the most helpful. Just compile your kernel as an ELF executable and use the "simple multiboot header" there.
What I did is create a simple multiboot ASM file with:
Code: Select all
MULTIBOOT_PAGE_ALIGN equ 1<<0
MULTIBOOT_MEMORY_INFO equ 1<<1
MULTIBOOT_HEADER_MAGIC equ 0x1BADB002
MULTIBOOT_HEADER_FLAGS equ MULTIBOOT_PAGE_ALIGN | MULTIBOOT_MEMORY_INFO
CHECKSUM equ -(MULTIBOOT_HEADER_MAGIC + MULTIBOOT_HEADER_FLAGS)
; The Multiboot header (in NASM syntax)
align 4
dd MULTIBOOT_HEADER_MAGIC
dd MULTIBOOT_HEADER_FLAGS
dd CHECKSUM
and then used my build script to build and link it:
Code: Select all
#!/bin/bash
nasm -f elf -o bin/mbhead.o code/mbhead.s
gcc -fno-builtin -c code/kernel.c -o bin/kernel.o
ld -o kernel.bin --oformat elf32-i386 -Ttext 0x100000 -e kernel bin/mbhead.o bin/kernel.o
and voila! (I think). While grub seems to like the kernel, and it seems to be booting, the catch is that since my kernel currently consists of a "while (1) do;", i'm not sure what is actually happening yet.
Good luck!
GRUB Problem... solved!
Posted: Fri Feb 21, 2003 10:22 am
by Mastermind