New BSD Installer

Freddie Cash fjwcash at
Fri Feb 17 21:50:11 UTC 2012

On Fri, Feb 17, 2012 at 1:38 PM, Andriy Gapon <avg at> wrote:
> And just in case:
> Unified Extensible Firmware Interface Specification Version 2.3.1, Errata A
> September 7, 2011 says:
> [snip]
>> Two GPT Header structures are stored on the device: the primary and the
>> backup. The primary GPT Header must be located in LBA 1 (i.e., the second
>> logical block), and the backup GPT Header must be located in the last LBA
>> of the device.
> I can not see any ambiguity or openness to interpretation in this paragraph.

Unless it's specified somewhere else (which is possible), in this
paragraph, "device" does not necessarily mean "physical disk".  "Last
LBA of the device" could be interpreted as "last LBA of the GEOM

The beauty of GEOM is that "device" is whatever logical mapping it provides.

After all, LBAs are logical addresses (it's right there in the name!),
not hardwired physical sector addresses.  ;)  If they were hardwired,
then how would internal sector remapping work?  ;)

Freddie Cash
fjwcash at

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