[BSD-INDIA] Booting GPT disk on non-EFI box.

[Ashish SHUKLA]

Arun Sharma writes:
> On Mon, Aug 3, 2009 at 8:25 AM, Ashish SHUKLA <wahjava.ml at gmail.com> wrote:

>> Hi all,
>> 
>> With the help of GRUB2[1], I'm able to boot my box (Intel DG35EC mobo and
>> Intel Core 2 Duo CPU) which has both the disks partitioned in GPT. I've
>> GNU/Linux and FreeBSD installed as primary operating systems. GRUB2 also
>> has support for booting FreeBSD kernels and loading FreeBSD modules[2]
>> directly without the need of loader(8).
>> 

> Yes - GPT works great for having many FreeBSD and  Linux partitions on a
> large disk. Most of the problems I experienced a few months ago had to do
> with generic problems HP laptop BIOSes had booting from external USB disks.
> I suspect that the timeout programmed in the BIOS is too small and before
> the boot sector could be read, the BIOS moves on to the next bootable
> device.

So nothing due to GPT ? BtW, the issue I encountered while setting up my
box is BIOS is not letting my HDDs boot which I found later is due to no
partition being marked active in MBR. Fucking Intel BIOSes...:(

> Windows (even the windows 7 beta) continues to have problems reading FAT
> partitions from the GPT partitioned disks - although I suspect that there is
> some GPT support in the OS.

lol.

> Same for Mac. You get a "Can't read the disk - format disk or eject?"
> type of dialog.

This is strange. While researching on this I've seen that Apple is the
one to support GPT in their EFI based Macs.

> The other choice that a BSD user needs to make is whether to a have:

> a) Single large protective MBR (partion type 0xee starting from 0 to the end
> of the disk)
> b) Mirrored MBR (the first 3 partitions the same as GPT, the fourth one
> being 0xee). Programs such as gptsync do this. Probably this makes windows
> and mac happy - although I haven't really benefited from it.

I thought of doing this but I didn't understand how would OS kernels
tackle this ? Are we going to get 6 device nodes for 3 partitions ? So I
dropped the idea :).

Did you tried FreeBSD's gptboot ? I think it also lets user boot from
GPT disk without need of EFI.

>  -Arun

> PS: I  had surprises with the freebsd 7.2 installer when installing to a GPT
> disk. Although some pieces of the installer knew about GPT, other parts
> didn't and I somehow ended up with a weird MBR partitioned disk. I fixed up
> the GPT manually post install.

I think FreeBSD team should write a Gentoo installation handbook like
document to install from tarballs directly which is the most reliable
way of all :-).

Ashish SHUKLA
-- 
Optimists say the glass is half-full,
Pessimists say the glass is half empty,
I says it's time for a beer run.
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