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new master boot record

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onx

Member
Joined
Feb 20, 2003
Location
CA
currently I have linux on one drive (120GB), and windows on another (80GB). When I installed linux on the 2nd drive (kubuntu), I assume it modified the mbr (which was on the 80GB drive) and installed the grub (at least I'm pretty sure it's grub) boot loader. Right now these two drives are like conjoined twins, I can't disable (or remove) one drive and still be able to boot into the os that is loaded onto the existing drive, but this is exactly what I want to do. How do I repair the MBR on the 80GB drive (the one with windows on it) so that it can boot all by its lonesome? I did a bit of research and found this on the ms site:

Link to M$ site
You can use the fixmbr command in Recovery Console to rewrite the MBR to resolve a corrupted MBR on a startup disk. However, running fixmbr overwrites only the master boot code, leaving the existing partition table intact. If the corruption in the MBR affects the partition table, running fixmbr might not resolve the problem.

Caution
Use this command with care because it can damage your partition table if any of the following apply:
A virus is present and a third-party operating system is installed on the same computer.
A nonstandard MBR is installed by a third-party disk utility.
A hardware problem exists.

The part where it says "A nonstandard MBR is installed by a third-party disk utility" can "damage your partition table" that kind of freaks me out a bit...What do you think my chances are with this method given my current setup, or is M$ just trying to cover it's tush with this warning? Is there a better way to accomplish what I wish outside of reformatting, reinstalling, and reloading a ton of backed up ****?

Thanks for your help.
 
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I would go ahead and run it, don't freak too much. I have seen that warning about 10 or so times and have yet to have it do any damage. If you are going to run fixmbr I would run fixboot right after.

fixmbr
fixboot
exit



Fixmbr repairs the startup partition's master boot code.

Fixboot writes a new startup sector on the system partition.

Exit quits the Recovery Console, and then restarts the computer.
 
First: fixmbr will work, no need to believe the MS scare tactics there.

Grub is installed in two places: the MBR which then loads the stage2 of grub, in your case from the 2nd harddisk in /boot/grub/ on your linux partition. That's why you can't boot when the 2nd drive is removed, cause then stage1.5/2 is missing
 
If you want to preserve your linux but still be able to remove its drive you can put the GRUB boot loader on a floppy disk. Boot into linux and log in as root and type the command:
grub-install /dev/fd0

You can now safely remove GRUB from the hard drive MBR with fixmbr command.

Without the floppy disk the computer boots directly to Windows

With the floppy disk the GRUB menu comes up
 
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