FreeBSD Installer Roadmap

[John Baldwin]

On Wednesday, February 23, 2011 11:15:09 am James R. Van Artsdalen wrote:
> On 2/22/2011 2:57 PM, Peter Jeremy wrote:
> > When that does come, it will probably be driven by BIOS and hardware
> > vendors dropping support for MBR.
> 
> MBR is not a BIOS concept.  MBR is an OS thing.  The BIOS does not care
> or know what kind of partitioning you use, or if you partition at all.

That is mostly true.  There are some SCSI BIOSes that would examine the MBR
and infer what C/H/S geometry the OS was expecting from the MBR.  The
original dedicated disk dummy MBR triggered a divide by zero in one of these
BIOS ROMs.

> A GPT disk with FreeBSD  should boot fine on a quarter-century-old IBM
> PC/AT, until FreeBSD's "don't support 80286" message.

Even a GPT has a legacy MBR (the PMBR) at the front of the disk (it marks the 
entire disk as in use by a special 0xee partition or some such).

-- 
John Baldwin