FreeBSD Installer Roadmap
John Baldwin
jhb at freebsd.org
Wed Feb 23 16:33:25 UTC 2011
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
More information about the freebsd-current
mailing list