Hard drive confusions

[#1]

WIth the re-installation of W7 and re-arrangemnt of hard drives I am now feeling somewhat confused about which drives are healthy, which have problems and which are on the way out. Let me explain...
Of the 5 internal drives Acronis Drive monitor infoms me that one (80GB Western Digital - out of warranty last October):

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S.M.A.R.T. Parameter          Raw value  Value  Threshold  Status Reallocated Sectors count    220            172  140          Fail

I reformatted the drive still with the same result.
I then ran the Windows version of Western Digital's Data Lifeguard and it passed.
Then I ran Seatools for Windows on the 80GB drive:

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SMART TEST        Pass Short Self Test        Pass Long Generic Test  Pass

As it's only 80GB and probably around 4/5 years old I'll most likely take it out (although I could use it for temporary storage). But what is the definitive way of testing a drive (apart from listening to clicks and other noises?
Of the other 4 drives Acronis shows the SMART data for each and no problems reported. But Data Lifeguard shows that the SMART feature is either turned of or unavailable for three of them including another WD 500GB drive!.
Why would one program display the SMART data but another not able to even for their own drives?

[#2]

You have a large-ish number of re-allocated sectors.
Reformatting (unless a low level format) would not attempt to rescue any re-allocated sectors.
You would need to wipe the re-allocated sectors table, run a low level format, write data to the whole disk,
then format it and see if you get great changes.

[#3]

Sectors get reallocated when they can no longer be read.  Whether you disc has 220 or 172 of these, it has a lot.  It's on the way out and I would  advise you to throw it away.
I don't think there is a definitive test for all hard drive problems but experience has taught me to distrust the tools provided by hard disc manufacturers.  After all, they have a vested interest in showing a positive result.

[#4]

The drive has a capability of re-allocating 220 bad sectors in total, so far 172 have been re-allocated which is above the SMART threshold of 140 and thus the drive has failed that status check.
While it has not actually failed yet, it may do soon so needs to be replaced before it finds more bad sectors.
Also low-level formatting now-a-days is generally not possible by the user.
Any drive testing will read the re-allocated sectors and not the original and thus pass.

[#5]

Thanks. It's good to have a better understanding of the SMART data.
Hard Drives seem to be quite the enigma. You can have one thrashing around for a number of years without issue yet have one that gets occasional use and fails within a year or even months.

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...After all, they have a vested interest in showing a positive result.

Still don't understand why WD's own software fails to pickup the SMART data for it's own disc whereas Acronis does.

[#6]

Quote from: Peter

The drive has a capability of re-allocating 220 bad sectors in total, so far 172 have been re-allocated which is above the SMART threshold of 140 and thus the drive has failed that status check.

Ah, so that's what the two numbers mean, thanks Peter.  I think the SMART failure threshold of 140 is a pretty high number.
Mav, the Western Digital and Seagate test software choose to ignore this SMART data because they want to minimise the number of hard drives returned under warranty.  If you doubt this, just consider your own case.   

[#7]

That does seem plausible except for the fact that I have two WD discs one of which the SMART Status says Pass and the other says Not Available.
I'm assuming the DOS version would report the same - I haven't yet seen the point of burning a CD for the purpose.

[#8]

Quote from: Peter

The drive has a capability of re-allocating 220 bad sectors in total, so far 172 have been re-allocated which is above the SMART threshold of 140 and thus the drive has failed that status check.

I can't speak for Acronis Drive monitor, but I don't think that's what those numbers mean. Usually the "normalised" SMART value is like a percentage, or out of some other number, and counts down towards the threshold figure. The raw value is the number of re-allocated sectors. e.g.
[tt]Attribute                    Value    Worst    Threshold    Raw value
Reallocated Sector Count      200      200      140          0[/tt]
The above is for the 320GB WD drive in my laptop, it has zero re-allocated sectors, so the value is still 200 out of 200. It doesn't say the actual number of spare sectors it has, it's probably more than 200.
[tt]Attribute                    Value    Worst    Threshold    Raw value
Reallocated Sector Count      090      090      036          444[/tt]
Although this 1.5TB Seagate Barracuda LP drive has re-allocated 444 (!) sectors, that has only reduced that smart attribute from 100 to 90, and it's still a long way from the threshold of 36. It's actually the drive in an iomega external drive - I consider it to be by far the worst drive I've bought so far.
Those values are just from smartmontools on Linux - all the SMART values, both the raw values and the normalised ones, are supplied by the drive itself. Some software may decide to give a big warning for any non-zero number of reallocated sectors. It's more of a concern if the number of re-allocated sectors keeps increasing.