If you want to understand how Grub boots and what it "sees", I'd suggest making a Grub boot floppy and then trying different things. If you have Grub installed (not necessarily as the bootloader: you just need the Grub package on the system), you can read the instructions for creating a boot floppy if you do '
info grub' then choose 'Installation' and then find the section on installing to a floppy disk (press 'q' to quit from the 'info' command). I think the commands are these:
Code:
/sbin/grub
root (fd0)
setup(fd0)
With a generic Grub boot floppy you can boot to the 'grub>' prompt and then "manually" boot your system. Grub has a useful filename completion feature. If, at the grub> prompt, you do: '
kernel (hd1,0)/ <tab>' Grub will list the directory of the partition that it recognizes as (hd1,0). You can drill down into the directories to find any file you want: '
kernel (hd1,0)/boot/ <tab>' will show the kernels and any other files and directories in the /boot subdirectory on partition (hd1,0) if the /boot directory exists.
The cool thing is, you can poke around extensively without ever booting your system until you are ready. The Grub boot floppy can also be used to install Grub to the MBR "natively" and it serves as a useful rescue boot disk.