[SeaBIOS] GPT disks in a BIOS world

[Gleb Natapov]

On Tue, Jun 05, 2012 at 10:58:43AM +0200, Fred . wrote:
> On Tue, Jun 5, 2012 at 5:21 AM, Kevin O'Connor <kevin at koconnor.net> wrote:
> > On Mon, Jun 04, 2012 at 07:11:30PM -0700, Ralf A. Quint wrote:
> >> At 03:36 PM 6/4/2012, Kevin O'Connor wrote:
> >> >On Mon, Jun 04, 2012 at 03:33:05PM +0200, Fred . wrote:
> >> >> http://mjg59.dreamwidth.org/8035.html
> >> >>
> >> >> Does SeaBIOS support GPT disk labels?
> >> >> Does SeaBIOS understand GPT disk labels? Is it aware of GPT?
> >> >
> >> >This is a common misunderstanding of the BIOS.  The BIOS doesn't do
> >> >anything with partition tables at all (at least according to the
> >> >available specs).  Thus, the BIOS doesn't care if it's a legacy
> >> >partition table or a GPT partition table.
> >>
> >> Excuse me, but isn't it the BIOS that after POST is initiating the
> >> boot process from the active partition?
> >
> > Not quite.  The BIOS loads the first sector of the hard drive (ie, the
> > MBR) into memory and runs the code found there.  It cares nothing
> > about the partition table.  It's quite common for the executable code
> > in that first sector to analyze the partition table, load yet other
> > code, and then jump to that code - but that activity is outside the
> > BIOS and is easily upgradable.
> 
> But does GPT disks even have a MBR?
Do you know this new site called google.com? You can try to ask it a
couple of question :)
http://www.petri.co.il/gpt-vs-mbr-based-disks.htm

> 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?
> 
> >
> > At least, that's what SeaBIOS does and what the available BIOS specs
> > call for (and what every boot loader I've seen expects the bios to
> > do).  But, who knows what crazy things various comercial BIOSes do.
> >
> > -Kevin
> >
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--
			Gleb.