formatting disk for FreeBSD : Detecting IDE Primary Master ...[Press F4 to skip]

[Ted Mittelstaedt]

> -----Original Message-----
> From: owner-freebsd-questions at freebsd.org
> [mailto:owner-freebsd-questions at freebsd.org]On Behalf Of Nerius Landys
> Sent: Saturday, January 26, 2008 12:04 PM
> To: Chris Whitehouse
> Cc: freebsd-questions at freebsd.org
> Subject: Re: formatting disk for FreeBSD : Detecting IDE Primary Master
> ...[Press F4 to skip]
>
>
> > Some motherboards had an upper limit on hard disk size which I think was
> > 32gb. Some drives have a jumper to limit the apparent size to 32gb (if
> > that was the size).
> >
> > Also I no longer have hardware to test this on but if it is a BIOS
> > problem I believe if you could put the hard disk in a newer machine for
> > the install it would then boot in the older machine as FreeBSD accesses
> > the disk directly, not through the BIOS.
> >
> > When he puts that big hard drive back in the old computer, he
> still won't
> be able to boot because to boot the BIOS reads the MBR on the
> hard disk and
> passes control to that program.

All BIOS code is written to check for firmware at locations
c000:0000 through c789:0000 during bootup - this is where add-in
cards like the Promise card that I indicated he should use, have
their firmware. When the CPU transfers control to that firmware,
it can overwrite BIOS parameters to allow booting to occur off the
hard disk on the add-in card.

Ted