John Nemeth <jnemeth%cue.bc.ca@localhost> writes:
> } But trying to boot this disk on an old mac doesn't work.
>
> Um, silly question, but why would you expect something designed
> to talk to a standard PC BIOS (gptmbr) to work on something that
> isn't a PC? At minimum you're going to need something like bootcamp
> or possibly rEFind. Note that I have never tried to get an Intel
> Mac booting. One of the Mac people is likely to be able to give
> you a better / more complete answer.
Actually that's a pretty good question...
By 'old mac', I mean an early 2008 MacBook Pro, which has a Core2 Duo
T7500, 2 x 2.20 GHz, and 4GB DDR2 RAM. So it's old, but not really that
crufty.
While you have a fair point that Intel Macs seem to be i386/amd64
machines without the usual BIOS crud, I have, on an even older Macbook
(still Core2 Duo) installed i386 NetBSD, with an MBR partition table,
and the normal NetBSD mbr bootblocks, and it boots fine off the hard
disk. So it does seem that Intel Macs can do the "load sector 0, run
it" approach, and enough BIOS calls for boot code to run.
But, my real question is:
If I install gpt boot blocks as above, on say a 4T SATA disk, and put
that in a regular Dell-built amd64 PC, is it likely to work?
and a further question:
I know /boot (with MBR) can skip the raidframe header. So given a
disk with a single MBR partition of type RAID, and an inside-the-RAID1
disklabel with raid0a starting at 0, booting works. (I'm sure because
I do this all the time.)
But, if I have gpt, with a RAID partition, and in the RAID1 have
another gpt label, and in that a partition, is there any way to boot
from that? Basicallly I'm thinking
sd0
A=gpt partition 1, type raid, starts at 1024, big
raid0 (so starts at 1024*64)
B=gpt partition 1, starts at say 1024+64+64
and would like the bootxx_ffsv2 code written to the beginning of
A to see type 'raid', skip 64, and then interpret gpt vs mbr and find
the active inner gpt partition.
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