Re: Blockbusting news, this is important (Re: Why are bad disk sectors numbered strangely, and what happens to them?)

[bill davidsen]

In article <200310180830.h9I8ULuc000419@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
John Bradford  <john@xxxxxxxxxxxx> wrote:
| > > BTW: Hard drives apparently use more sophisticated algorithms,
| > > involving measuring head signal level even when there is no problem
| > > reading the data, and eventually remapping a sector on read before the
| > > information is lost.
| > > 
| > 
| > Which means cat /dev/hda > /dev/null makes sense in
| > cron.weekly...
| 
| Indeed.  Some drives can also do a timed defect scan using S.M.A.R.T.

You make the point I was going to question, is the cat (dd?) better than
a S.M.A.R.T. scan? I would think that the scan would be more likely to
be doing some special error checking, like turning off one level of ECC
or similar, and might see things a normal read might not. In other
words, the difference between no uncorrectable errors and no errors.

I am thinking of something like a C2 scan on a CD, to get error
detection without error correction.
-- 
bill davidsen <davidsen@xxxxxxx>
  CTO, TMR Associates, Inc
Doing interesting things with little computers since 1979.
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