[SeaBIOS] GPT disks in a BIOS world

[Ivan Shmakov]

>>>>> Kevin O'Connor <kevin at koconnor.net> writes:
>>>>> On Tue, Jun 05, 2012 at 10:58:43AM +0200, Fred . wrote:

[…]

 >> 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?

 > 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.)

	Check, e. g., [1].

[1] http://en.wikipedia.org/wiki/Unified_Extensible_Firmware_Interface

 > The BIOS loads the first sector of the hard drive into memory and
 > executes the code found there.  GPT partitioned disks do arrange to
 > be able to place boot code in the first sector of the hard drive.

[…]

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