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Date: Fri, 06 Aug 2004 15:17:36 -0400
From: Gary Corcoran <garycor@comcast.net>
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Subject: Re: Fwd: How to read bad blocks error message & marking of same
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Mike Meyer wrote:

> Modern drives deal with bad block substitution all by themselves.

Umm - not quite, right?  That is, if a block "goes bad" and you get
a read error, the drive isn't going to do any "substituting" at that
point.  You'll just continue to get the read error if you try to
access (read) that block.  It's only when you allow another *write*
to that block (e.g. by deleting the original file and writing new
files) that the drive will automatically substitute a spare block
for the one that went bad.

> By
> the time you've got blocks going bad that the OS sees, the drive is in
> really sad shape. You should replace it with a new drive ASAP.

If, after you have (for certain!) overwritten the bad block(s) and
you still get errors, then yes the drive is on its way out.  But
simply getting a read error (without any overwrite attempt) from
a block or two doesn't necessarily mean that the drive is turning
to mush, now does it?

Gary