Alan Cox wrote:
> > Reading this thread, I see that many have a misconception. Bad blocks
> > will not be found when someone tries to write to a bad sector! As
>
> Actually on IDE and modern SCSI disks they will be. The drive does it for
> you without you knowing. It also schedules its own I/O, it lies about
> geometry and it does transparent block remapping.
I've been wondering about this for years. I've seen drives "grow"
defects. For example, over 10 years ago, I accidentally bumped my knee
against the underside of the table where the computer was sitting.
Bang! 5 bad sectors!
Similarly, I've seen IDE disks get bad spots. Wether that's due to
marginal blocks getting OKed at the factory, or physical abuse, I
don't know.
On SCSI disks, I've also seen the term "grown defect list" which on
good disks tends to be empty. However, the provisions are there.
Anyway, if a disk finds a block to be unreadable for some reason, it
cannot do anything else but report error. Possibly if you issue a
write request for that block, it could reallocate the block, however,
I've tried "fixing" disks with badblocks by doing a
dd if=/dev/zero of=/dev/<disk>
but the bad blocks remained in place.
So how DO I trigger a reallocation of a grown bad block?
Roger.
-- ** R.E.Wolff@BitWizard.nl ** http://www.BitWizard.nl/ ** +31-15-2137555 ** *-- BitWizard writes Linux device drivers for any device you may have! --* * Common sense is the collection of * ****** prejudices acquired by age eighteen. -- Albert Einstein ********- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Sat Apr 15 2000 - 21:00:20 EST