Re: ATA 4 KiB sector issues.

[H. Peter Anvin]

On 03/10/2010 02:46 AM, Johannes Stezenbach wrote:
> On Tue, Mar 09, 2010 at 04:32:04PM -0800, H. Peter Anvin wrote:
> > It can.  The BIOS doesn't care about the partition table at all --
> > all it does is load the MBR.
>
> A little story for your entertainment pleasure:
>
> I have a Gigabyte GA-MA78GM-S2H board, and during install
> turned off the power after partitioning but before formatting
> any partition because I got distracted by something else.
>
> Result: System could not boot anymore, BIOS hung before
> I could get to the "select boot device" screen. This also
> happened when I removed the hdd from the boot device
> list in BIOS. The last BIOS message was "Verifying DMI Pool Data"
> and you can find numerous similar reports by searching for
> 'gigabyte bios hang "Verifying DMI Pool Data"'.
>
> In my case it worked to switch the SATA mode from AHCI to
> something else, then wipe the partition table and switch
> back to AHCI.  But I read on the net that some people had
> to format the drive in another PC, or hotplug it after the BIOS
> got past "Verifying DMI Pool Data".

Well, yes, there are buggy BIOSes of a gazillion varieties.  A fair 
number of them read the partition table to try to guess what C/H/S 
geometry the user intended.  However, the GPT spec specifically uses a 
"Protective MBR" to guard against this and other issues like it; it 
makes the entire disk look to MBR-reading software like a single fully 
partitioned disk with one large partition on it.

	-hpa
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