Re: Cannot boot xp
On Tue, Feb 22, 2005 at 01:51:20PM +0000, Floris Bruynooghe wrote:
> On Tue, Feb 22, 2005 at 01:28:01PM +0100, xerces8 wrote:
> > From: "xerces8" <xerces8@butn.net>
> >
> > BACKUP the partition table to somewhere where you can access
> > it if you break the disk layout ! Like on a floppy or network drive.
> > "sfdisk -d > part_table_backup" is a good backup IMO.
Good call:)
> "dd if=/dev/hda of=/floppy/mbr.backup bs=512 count=1" looks like a
> better one to me. Altho that copies the mbr as well which might be
> undesirable under certain circumstances. IIRC only the last 64 bytes
> of that file will be the partition talbe but you should really check
> these things before you do them.
Close. The MBR is 512 bytes, and includes the partition table. The
last two bytes are a magic number "0xAA55" (or byte-swapped). The 64
bytes previous to that are the partition table, with 16 bytes per
partition. And the other 450 bytes are machine code, usually starting
with a jmp instruction, possibly with a couple bytes of ASCII (like
the "L" in LILO).
Justin
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