booting off GPT partitions

Dimitry Andric dimitry at
Thu Jan 28 12:26:15 UTC 2010

On 2010-01-28 13:06, Robert Noland wrote:
> John or Marcel can correct me, but I don't think that this is an issue.
> The bootstrap is located in the pmbr in sector 0 and the GPT headers and
> tables are in sectors 1 - 34.  The bootstrap code knows how to read the
> GPT tables and can deal with>  2 tb lba's.

Ah yes, I see it now.  It uses EDD packets with the BIOS int 13
interface, which apparently have a 64-bit LBA.  This should support up
to 8 ZiB with 512-byte sectors...

OTOH, I have no idea how well most BIOSes actually implement this.
Since many OSes simply don't support anything over 2^32 sectors, I would
not be amazed to find much BIOSes out there that behave the same.  Or am
I too paranoid now? :)

More information about the freebsd-questions mailing list