James Courtier-Dutton wrote: > I thought that valid boot sectors have a checksum or some kind of > signature bytes. It might be worth verifying that it is a valid boot > sector before blindly using it. If it is not a valid boot sector, one > might as well fill it with zeros.
Which field are you thinking of here? There's the (optional) 32-bit disk signature at 0x01b8 (immediately following the executable code) and the 16-bit MBR signature at 0x01fe. From what I can see, neither of these would be suitable. The disk signature is optional and is only intended to be a unique identifier. The "MBR signature" is intended to signify a valid MBR but it's not based on any kind of checksum - if the field contains "0xaa55" it's valid, any other value and it's not. I just checked a bunch of devices that have valid MSDOS partition tables but do not have valid boot code (removable USB devices, some auxiliary HDs and a bunch of LUNs on my iscsi test box). All of these had the 0xaa55 signature, but no valid bootcode at offset 0, so I don't think we can use this as a check. Regards, Bryn. _______________________________________________ parted-devel mailing list [email protected] http://lists.alioth.debian.org/mailman/listinfo/parted-devel
