[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]

Re: Triple boot:XP,ubuntu&FC5 grub failed

Mike McCarty wrote:

The BIOS does NOT search the partition table for an active partition.
It is the code in the MBR which does that. All the BIOS looks for
is the first physical sector on the physical volume having the BOOT
RECORD signature (AA55) in the last two bytes. The BIOS accesses the
disc in a physical manner (LBA translation aside). It knows nothing
about partitions. Indeed, there are more than one way of partitioning
discs, and the "traditional" method is not the only one. Anyway, if
the BIOS finds the BR signature in the first physical sector, then it
simply loads it to 0000:7C00 (IIRC) and jumps to it. [NB: The processors
all reset to REAL mode, so this is not a selector address, but a
segmented address.]


So if I want to install grub onto partition 2 of my first drive and have no Grub installed into the MBR, the BIOS will not start loading whatever is in the first sector of my second partition? I have not tried to load grub into a partition and then make the partition active. I thought that I read that someone else was loading grub from a partition. I changed the active partition for the other OS and the OS which was on the active partition booted. When I changed the active partition to the other "other" OS, the secondary OS booted. I assumed that grub loaded in a similar way as the other OS to Load the Linux OS with the information grub puts into the selected partition.

I'm confused a bit on what grub is capable of. I'm curious enough to experiment on a computer. I want to try to run two different Linux distributions and be able to toggle the active partition in my experimenting. (Grub installed in the selected partition, no grub in the MBR)


Many receive advice, few profit by it.
		-- Publilius Syrus

[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]