Re: using GPT support in BIOS boot

[Thomas Mueller <mueller6724%bellsouth.net@localhost>]

> Just a quick summary of how to use the new GPT support in
> the x86
> boot stack.  (sysinst doesn't understand this yet.)
 
> # gpt create wd1
> # gpt add -b 64 -s 2097152 wd1
> # dkctl wd1 addwedge wd1_1 64 2097152 ffs
> # newfs -O2 dk0
> # installboot /dev/rdk0 /usr/mdec/bootxx_ffsv2
> # gpt biosboot dk0
> # mount /dev/dk0 /mnt
> # cp -p /usr/mdec/boot /mnt/
 
> That's the basics, you'll want a kernel and root file
> system
> on dk0 too to completely test this out.

> Features:
> - You can boot from a root partition at or above 2TiB if
> your BIOS
>   properly supports block addresses above the 32-bit
> barrier.
 
> Limitations:
> - The GPT MBR only supports 128 partitions (the default and
> minimum).
> - "/boot" only understands the first 26 partition entries
> (hdX[a-z]).
 
> Thanks to Mike M. Volokhov for his work during GSoC 2009
> that
> made this possible.
 
>     Jonathan Kollasch

Some questions on my part:

What versions of NetBSD is this good for?  Only 6 (current)?

Would NetBSD be able to see only the first 26 partitions?  Would NetBSD 
partitions such as /, swap, /home all be MBR partitions, or would they be 
subpartitions as is done when using traditional fdisk on hard disks < 2 TiB?

Can part of the disk < 2 TiB be reserved for OSes not aware of GPT, such as 
FreeDOS?

How would NetBSD be installed if sysinst can't be used?  Just unpack the sets 
over the root directory and edit some of the files under /etc?

Where does one get gpt and dkctl, what package do they belong to?  Or will they 
be part of NetBSD 6 (current) and on the installation CD?

I wouldn't use gpt on my present 40 GB hard disk but am planning to buy a new 
computer with amd64 multicore CPU and possibly Western Digital's Caviar Green 3 
TB hard drive, not that I could use > 2 TB immediately, but to be more prepared 
for the future.

I can't really see how I'd use > 26 partitions, even with FreeDOS + NetBSD + 
FreeBSD + Linux.

Tom