dual booting

[Lennart Sorensen]

On Sat, Jan 02, 2010 at 02:16:30PM -0500, D. Hugh Redelmeier wrote:
> GPT is a bit of a mystery to me.  Not so much the theory.  Just which
> tools and environments work with GPT?  Should we all switch to GPT and
> be done with the old style?

Pretty soon you will have to.  DOS style partitions can not go larger
than 2TB drives.  I have already had to start using GPT on raids.

> Yeah.  I had one machine set up that way.  Mostly because I found
> Vista so unwilling to survive a Linux installation.

Well gparted can resize vista's ntfs.  The vista bootloader is extremely
picky about the filesystem details, and often resizing the partition
makes it stop booting.  Booting the install DVD and running the boot
repair fixes it though, so it isn't that hard to deal with (other than
the fact most machines don't ship with a real isntall DVD).

> When I asked the BIOS to boot from the second (Linux) drive, drive
> naming in Linux changed.  So I had to patch up the installation.  This
> was over a year ago, so I don't remember what I had to change, but I
> think it was /boot/grub/{menu.txt,grub.conf}.  Using UUID in
> /etc/fstab should fix any problems there.

Certainsly helps.

> I don't want to install a second drive to dual boot.  I keep Windows
> if it was bundled with the machine, but I don't want to waste a whole
> drive on it.  All I seem to do with MS Windows is apply updates (to
> Windows and to firmware).

Hmm, many systems seem able to do bios updates from the bios directly
using a USB key.

> When I've installed Linux on a system with pre-installed Vista, the
> main problem is with resizing the Vista partition.  Vista itself can
> resize, but it never seems willing to give up much space.  Ubuntu's
> partition editor (gparted, I think) can resize Vista partitions, but
> it damages them.  What works for me is to do the resize in Ubuntu and
> immediately reboot Vista; it will complain and then fix up the
> partition.  Then it is safe to install Linux.

The resize in vista only shrinks the partition without moving data,
gparted has no issue moving data.  Using the boot repair will always
fix it after a resize.

If you don't have a real vista DVD then there is fortunately a repair
CD for vista that contains the needed tools.  See here for example:
http://neosmart.net/blog/2008/windows-vista-recovery-disc-download/

> What filesystems don't leave the first sector as a boot record?

I don't remember if btrfs does.  I was probably thinking more of grub's
stage 1.5 which is not 1 sector in size.  Not that the MBR helps with
that either.

> I try to install bootloaders on the boot record of the partition.
> Unfortunately, some Linux installers (Fedora 11 and 12, and maybe some
> Ubuntus) claim to be willing to do this but have curdled the MBR in
> the process.  I've not dug into this because testing is so laborious.
> 
> I think (but do not know) that the traditional MBR can only boot from
> a primary or extended partition's boot record, not a logical
> partition's boot record.  But Grub and LILO can chainload from any of
> those.

Correct, only a primary partition can be booted from by the MBR.
Debian includes a tool with a better MBR that has the ability to boot
from any partition using a little menu.  I used to use that a lot.

> I often have several Linux installations on a system.  There are at
> most 4 primary partitions, and at most 3 if there is an extended
> partition.  MS Windows typically takes 1 or 2 primary partitions (one
> for the NTFS filesystem and one for the restore partition).  So some
> of my Linux installations end up in logical partions.
> 
> Why do I have multiple Linux installations?  Because I almost never
> upgrade an installation -- I create a parallel installation of the
> newer version.  Then, if the new one is unsatisfactory, I can still
> run the old one.

Sounds very time consuming and like a waste of disk space.  I always
upgrade and so far that hasn't failed me yet (well since I moved to
Debian in 1999 that is, before that upgrades of redhat often made a mess).

-- 
Len Sorensen
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