Bad Sectors

  • Thread starter Thread starter Gary
  • Start date Start date
Arno said:
Well, do it any way you like. It is not my job to
prevent you from shooting yourself in the foot or
using inadequate procedures.

A competent approach to the problem looks differently though.

Arno
Click to expand...

Um no, if I am getting BSOD when booting up Windows and I suspect the
HDD after checking other possibilities else out and HDTune shows a bad
block in red and then swap out the HDD and no more BSOD then that is a
job well done and in a fraction of the time it would take you. You can
claim I am incompetent all you like but that doesn't make it so.
 
Well, I think I still do not undertsand the seek error rate attribute,
Click to expand...

Here are two examples for two Seagate ST3500630AS drives:

ID# ATTRIBUTE_NAME FLAG VALUE WORST THRESH TYPE UPDATED
WHEN_FAILED RAW_VALUE

7 Seek_Error_Rate 0x000f 035 024 030 Pre-fail
Always In_the_past 54443054162961

7 Seek_Error_Rate 0x000f 059 048 030 Pre-fail
Always - 1507770244954


Convert the raw decimal attribute values to hex:

54443054162961 = 0x318402e76411 (drive A)
1507770244954 = 0x015f0e1c1f5a (drive B)

AIUI, the number of seek errors is stored in the uppermost 16 bits of
the 48-bit attribute value, and the total number of seeks is stored in
the lower 32 bits.

So for drive A,

# seek errors = 0x3184
# total seeks = 0x02e76411

The normalised attribute value is logarithmic and appears to be
calculated as follows:

Normalised value = -10 log (seek errors/total seeks)

If the number of seek errors is 0, then use a value of 1.

For drive A, this works out as ...

-10 x log(0x3184 / 0x02e76411) = 35.8471493

For drive B it is ...

-10 x log(0x015f / 0x0e1c1f5a) = 58.2893528

Not exactly right, but very close ...

The worst case value of 24 corresponds to an error rate of ...

-10 ^ 2.4 = 1/251

.... ie one error in every 250 seeks.

- Franc Zabkar
 
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