Can't I get a /dev/one?

[Benjamin J. Weiss]

On Thu, 15 Jul 2004, Rick Stevens wrote:

> Benjamin J. Weiss wrote:
> > I believe that this is what is called a "low level" format.  IIRC, it 
> > formats all of the sectors, both good and bad and resets the flags.  Then 
> > it reserves a bunch of sectors as spares.  Then it tests all of the 
> > sectors to see if they'll hold the data properly.  If the software detects 
> > a problem, it flags the bad sector and brings a spare into use, just as 
> > James said.
> 
> I used to work for Micropolis and we made hard drives.  All hard drives
> have bad sectors on them.  The maker reserves a bunch of good sectors to
> be used as replacements and the first format tags the bad sectors and
> modifies a remapping table on the drive which causes it to go to one of
> the spares whenever one of the bad sectors is referenced.
> 
> As time goes on and other sectors go bad, a "low level" format finds
> the new bad sectors and further modifies the remapping table to use more
> of the spare sectors.  S.M.A.R.T. drives are supposed to be able to do
> this on the fly.
> 
> Eventually, the drive will run out of spare sectors and you can't
> successfully low level format it any more.  The manufacturer can wipe
> the original remap table and go through it again, but by that time the
> drive is usually well past its MTBF and it's somewhat silly to try to
> push it any further.

Thanks, Rick!  I'm glad to get my misconception fixed. :)  Like they say, 
you learn something new every day, and this was today's. ;)

Ben