When a read/write head crashes into the spinning disk because of power
interuptions or jarring, particles break loose and cause parts of the drive
to become unreadable. These particles could move around if the drive was
jarred or the drive position was changed. This used to be a very common
problem in early hard drives but modern drives have largely eliminated this
problem.


"Andy Cuffe" wrote in message
...
On Sat, 4 Sep 2004 00:17:31 -0300, Chaos Master
wrote:

Hello people.

I have an oldish 800MB hard drive here which is still working (it stores
some
audio files).

Recently, after a power surge, it developed a "bad block" (4kb marked as
bad),
but it still works correctly.

Q: What is a "bad block" in a hard drive?
Physical damage?

Thanks


If you're worried about the drive, go to the manufacturer's web site
and download their diagnostic utility. It will test the entire drive
and tell you if there's anything wrong with it. It may even be able
to repair the bad sector. I always do this to a drive, even if it's
new. You'd be surprised how many drives seem fine, but fail to meet
factory specs.
Andy Cuffe