>Ken Fuchs wrote:

>> I'd recommend saving the current MS Windows 98 MBR (first 512 bytes of
>> the raw boot disk usually either /dev/hda or /dev/sda) to a file as soon
>> as possible using Linux.

Callum Lerwick wrote:

>Why bother backing it up? Just boot a DOS/Win floppy or CD or whatever,
>and 'fdisk /mbr'. Bam, its back. I wonder if that MBR code has even
>changed in 20 years... I think NT uses a different MBR...

MS "fdisk /mbr" simply overwrites the Grub MBR (which is the opposite of
what the original poster wants to do).

Grub is just as easily installed in the MBR by booting the rescue floppy
and executing "grub-install /dev/hda", considering that /dev/hda is
almost always the boot disk for ATA disk based systems.

Backing up the MS Windows 98 MBR from Linux allows one to restore it
from Linux.  That's especially nice when one can't find MS boot media.

However, my purpose in backing up the MS W98 MBR was to use it later in
case chain loading MS Windows 98 from the Grub MBR boot loader fails.

>Anyway, on multiboot systems I recommend putting GRUB/LILO on your Linux
>root partition, and setting your root partition 'active'. This will
>cause the windows MBR code to jump to the boot code on your root
>partition, and it will happily boot grub/lilo for you from there.

Doesn't this require an MS Windows MBR or other boot loader that looks
for the active partition?  Not all boot loaders installed in the MBR
check for (or at least act on the presence of) an active partition.

Grub/lilo in a partition boot record will not be loaded as soon as
another partition is made active (by accident).

Do you really want MS code in your MBR?  I'd rather have grub there.

In my opinion, the concept of an active partition is a bad idea.  It is
just another variable that must be considered in the boot process that
causes the side effect of (sometimes unexpectantly) loading another boot
loader.

However, if you do use MS Windows 98/98SE/ME a lot, including
reinstalling it, don't mind having MS code in the MBR, don't do anything
that accidentally changes or erases the active partition marker,
Callum's idea should work with excellent results and minimum maintenence!

>The nice thing about this setup, is if windows decides to take over the
>system, all you have to set your Linux root partition active again,
>which can be done with windows FDISK, and you've got GRUB/LILO back. No
>digging for a Linux rescue disk or CD, you just need the windows that's
>hopefully already booted up on the system...

My X Window System which is the window system I'm almost always using,
doesn't seem have a active partition marking function.  :)

Callum's suggestion of installing grub/lilo in the GNU/Linux root
partition would be perfect for MS Windows users who are adding GNU/Linux
to their system, except for a couple potential problems:

1) If the GNU/Linux distribution is (being) installed with a /boot
   partition, the grub/lilo loader should be installed in the boot
   partition rather than the root partition.  This is often done to
   avoid the BIOS boot limitations of earlier machines; hopefully the
   boot partition is in range; the root partition may be not be.

2) The MS Windows 95/98 MBR loader uses the BIOS functions to boot the
   operating system or boot the active partition's boot loader.  If
   either of these is beyond the BIOS disk routines' range, booting
   fails.  Grub uses the BIOS disk routines only to boot the initial
   stages of itself which must be in BIOS range, but its later stages
   and the operating systems it boots have no range limitations since by
   this point, grub is using another set of disk routines that do NOT
   use the BIOS disk routines.  Newer MS operating systems and newer PCs
   don't have these limitations, but for older machines with large (>8
   GB) drives with some partitioning, putting grub in the MBR is the
   only way for the system to dual boot MS Windows and GNU/Linux.

Earlier MS Windows operating systems should always be installed near the
beginning of large disk to avoid BIOS booting limitations of its MBR
loader.

Callum's suggestion has a lot of merit, but it isn't always the right
boot loader setup.  Putting grub/lilo in the MBR versus a partition has
many pros and cons and is a personal decision that each of us must
make.  In the end, it doesn't matter which booting method is used as
long as we are comfortable about the way it works (and know how to fix
it when it breaks).

Sincerely,

Ken Fuchs <kfuchs at winternet.com>



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