On Tue, Jun 05, 2012 at 11:39:35PM +0700, Ivan Shmakov wrote:
Kevin O'Connor kevin@koconnor.net writes: On Tue, Jun 05, 2012 at 10:58:43AM +0200, Fred . wrote:
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But does GPT disks even have a MBR? Isn't the GPT a replacement for MBR? If the disk doesn't have any MBR, does the BIOS load the first sector of GPT?
To note: FreeBSD's version of “protective MBR” (pmbr.s) has the support for GPT and will load the “big” bootloader from a GPT partition of a specific type.
I'm not sure how I could be more clear on this. SeaBIOS cares nothing about the partition table.
Not even about the 0x55 0xAA magic?
SeaBIOS does check that the last two bytes of the first disk sector is 0xaa55 before executing code there as a sanity test.
No BIOS spec (that I'm aware of) requires the BIOS to care anything about the partition table.
The problem is that the BIOS specs are currently being replaced with the new UEFI ones, and UEFI boot sequence may be much more complex (but, AIUI, even in the simplest case, it has to support the MBR and GPT partition schemes, /and/ the FAT family of filesystems.)
UEFI is very complex.
I've seen companies push UEFI as a requirement for >2Terabyte drives - but that's really not true.
-Kevin