hmmm found the below info
discussions.virtualdr.com
A hard drive contains platters that are magnetic media capable of
having the magnetic state of areas on them changed and having this
magnetic state retained/maintained. Data is held on a hard drive by
representing it in binary form (1s an 0s). The way these 1s and 0s
are physically represented on a drive's platter(s) is by having
areas (spots) that are magnetically charged or not. The 1's are
represented by charged (positive and negative) areas, the 0s are
represented by uncharged areas (there is a level of tolerance by
which an area is deemed charged or not). When a sector becomes
"bad", or is deemed to be so, it is because areas within it no
longer appear to be able to maintain a sufficiently magnetized
(postitive or negative) state (charge) to represent the 1's data in
those areas. Bad sectors are marked (flagged) in a table and, when
possible, remapped to one of series of spare sectors all hard
drives have.
Now, sometimes an area is deemed (flagged) as bad when it may in
fact not really be. Perhaps some oddity during the write process
caused the spot to be too weakly charged (which really shouldn't
happen or at least not often as that is a sign of another problem),
rather than it being a case of the actual area on the media being
bad in some way. Using the appropriate utility a sector previously
marked as bad can be un-marked (taken off the bad list). And you
can use one of these utilities to put a sector back in service (so
to speak). Nothing is "fixed", just made available for use again as
is.
Few if any sectors in modern hard drives should go bad after they
leave the factory. Occassionaly maybe a sector may be erroneously
flagged as bad when it really isn't, but this should be very rare.
And if sectors do start cropping up as bad it is time to start
thinking about another hard drive. Bad sectors can't get repaired,
not by the user (not even with the hard drive manufacturer's
utilities).
if the above info is indeed true, does that means freezing will
actually affects the harddisk polarity???
