chkdsk

[William B. Lurie]

John, I don't find the instructions for chkdsk clear.
Running it several times, first it finds and fixes
misplaced or stranded files and deletes some, finally
all is apparently clear, but then running Seagate's
SeaTools, that finds one bad sector.Repeating that
test, the bad sector remains. Is chkdsk saying that
there is nothing for it to fix any more, and the bad
sector that *is* there has been marked and taken out
of service?
Bill Lurie

 

[Michael Solomon \(MS-MVP\)]

Pure and simple, chkdsk is not very robust. It might find and fix a bad
sector but it does tend to miss a lot of things that are found by more
robust tools. I would tend to believe SeaTools or any manufacturer's hard
drive diagnostic or chkdsk. My experience is, when I've run into a
diagnostic turning up bad sectors, even one, it's not long before the drive
starts to fail. Generally, this is an early warning sign.

 

[William B. Lurie]

Pure and simple, chkdsk is not very robust. It might find and fix a bad
sector but it does tend to miss a lot of things that are found by more
robust tools. I would tend to believe SeaTools or any manufacturer's hard
drive diagnostic or chkdsk. My experience is, when I've run into a
diagnostic turning up bad sectors, even one, it's not long before the drive
starts to fail. Generally, this is an early warning sign.

Thank you, Michael. SeaTools itself is confusing, at least to me.
I don't expect anything to actually repair the bad little piece of
hardware, but I recall that some tools will attempt to move whatever
data is in that sector, to an unused sector, and permanently mark
the affected sector as unusable, locked out, or whatever. It isn't
clear to me that either SeaTools, WD's Data Lifeguard tools, or
chkdsk, do this effectively. What does not surprise me is that
a tiny percentage of a physical drive with 80 billion bytes of storage,
mass-produced and selling at bargain prices, will develop problems in
a reasonably short time.

I expect more of this sort of thing to happen, as more and more
gets squeezed into smaller spaces, and maybe my fanatic attitude toward
exact backup will become more understandable.

-- Bill Lurie

 

[Michael Solomon \(MS-MVP\)]

If chkdsk finds the sector, it will try to move the data off of it and will
mark it unusable. Other tools will do that as well, assuming they see the
sector. It's possible SeaTools is doing that as well and the warning it may
be giving you might simply be the same sector that it is finding, unusable
or not. You would need to check their documentation as to what it does with
any data it finds.

My experience is, usually they are just fragments mixed with a lot of
machine code. Sometimes it may help you piece together a lost file but the
overall file created of such data is generally useless otherwise.

 

[William B. Lurie]

Yhanks again, Michael. I'm waiting for Seagate to tell
me what they actually 'repair'.
WBL

 

[Michael Solomon \(MS-MVP\)]

You're welcome.

I've never seen anything that actually "repairs" a bad sector. Usually, the
utility just marks it bad and it is no longer used. But, as I said, my
experience is, this is usually a sign the drive is going to fail and I begin
making preparations and then get a replacement drive.