Backing up the MBR

after Windows messes it up. In Linux, the “dd” command can read and
write to/from raw disks and files. If you have a floppy drive, creating
a boot disk is as simple as putting a floppy in the drive and typing

$ su
<type password>
# dd if=/dev/hda of=/dev/fd0 bs=512 count=1

This makes an exact copy of the MBR of the first hard drive, copying it
to a floppy disk. You can boot directly from this floppy, and see your
old boot menu. You can restore it by switching the “if=” and “of=”
(input file, output file) parameters.

If you don’t have a floppy drive, you can back it up to a file with

# dd if=/dev/hda of=/home/john/boot.mbr bs=512 count=1

Then you can boot into a CD-ROM distribution such as Knoppix, or often
use your Linux distribution’s installation CD to boot into rescue mode,
and restore it with:

$ su
# dd if=/mnt/hda5/john/boot.mbr of=/dev/hda bs=512 count=1

(you’ll need to find and mount the partition containing the directory
where you backed up the MBR for the “if” parameter–this is an example).


John Locke