On Fri, 2009-12-25 at 05:21 +0800, Robert Millan wrote: > I think making a backup is a fine idea, but I'd rather avoid the "option > creep". It doesn't hurt to simply dump the files in /boot/grub/. If user > later discovers that valuable data was overwritten, she can figure out > how to call dd just as she can figure out the right parameters for > grub-install.
OK. My only concern is the start position of grub core.img (as in disk sectors) is a variable (see find_usable_region_xxx). This ends up the backup file is not a simple dump. I used below format in my patch. <512 bytes MBR> + <U64 start position> + <sizeof(core.img) old sectors> Option 2 is to put the start position in a separated file. Option 3 is to use the information in boot.img (as I used in my patch as a verification method) to get the start position, i.e. `od -j92 -N8 -An -td8 $grubdir/boot.img`. Option 4 is to backup everything from MBR to the end of core.img (including the holes in the middle). This ends up with a bigger image. Option 1~3 requires the recover has the knowledge of the backup file format somehow, but a simple dd is enough for option 4. What do you think? Thanks, -yi _______________________________________________ Grub-devel mailing list Grub-devel@gnu.org http://lists.gnu.org/mailman/listinfo/grub-devel
