HARD DISK MONITORING

Hard disk case: surface problems

This example shows the status a Samsung 80 GB IDE (PATA) hard disk.

Hard disk problems reported

very slow Windows boot time
disk check starts regularly with Windows and reports file system errors
files and folders are hardly accessible
folder and file access is very slow

First hard disk checks

Initially, the hard disk health reported is 9 %. The text description shows numerous problems with the hard disk:

There are 137 bad sectors on the disk surface. The contents of these sectors were moved to the spare area.
The drive found 1 bad sectors during its self test.
Based on the number of remapping operations, the health of the disk was decreased in different steps.
There are 68 weak sectors found on the disk surface. They may be remapped any time in the later use of the disk.
19371 errors occured during data transfer. This may indicate problem of the device or with data/power cables. It is recommended to examine and replace the cables if possible.
It is recommended to backup immediately to prevent data loss.

Power on time: 229 days, estimated remaining lifetime: 12 days

Hard disk tests performed

First (as suggested by the Frequenty Asked Questions page) the hardware self tests are used: Disk menu -> Short self-test and Disk menu -> Extended self-test. These tests check the functionality of hard disk components in general and the extended self-test performs a surface analysis. As expected, these hardware self-tests quickly respond with an error message:

Hard disk extended self test failed because of read element

Then a non-destructive surface test performed: Disk menu -> Surface Test -> Read Test. It confirms that the hard disk surface contains problems (mostly the "weak sectors" which are not yet reallocated but cannot be used at this time):

Bad sectors and damaged blocks affecting the whole hard disk surface

The Disk menu -> Surface Test -> Reinitialise Disk Surface test slightly improved the situation. It forced the hard disk drive to verify the complete surface area, reallocate possible bad sectors, examine weak sectors to check if they should be re-allocated or can be used without problems, so we expect that the reallocated (bad) sectors will increase and the weak sector decrease.

The result was that the reported number of bad sectors increased to 155 and the number of weak sectors decreased. The health improved to 14% - but this is still considered to be "bad".

The user preferred to continue using the hard disk. However, after a week of normal usage, problems started to appear again (notice that all error-counters have increased number):

There are 166 bad sectors on the disk surface. The contents of these sectors were moved to the spare area.
Based on the number of remapping operations, the health of the disk was decreased in different steps.
There are 103 weak sectors found on the disk surface. They may be remapped any time in the later use of the disk.
30227 errors occured during data transfer. This may indicate problem of the device or with data/power cables. It is recommended to examine and replace the cables if possible.
It is recommended to backup immediately to prevent data loss.

The health decreased to 7%. Estimated remaining lifetime: 7 days. This is the last known status of the hard disk.

One week elapsed after the above situation reported, then the hard disk failure happened (died completely). Windows did not start at all, the partition and file system corrupted and data recovery was not possible even at sector level when the hard disk was connected as a secondary drive for disk examination and data recovery.

Note that (even when the problems reported and before the failure happened), the "threshold" level set by the manufacturer was not reached. That would be required to ask for a warranty replacement hard disk (at that time the reported hard disk health would be 0 %). It means that even when data loss happened, warranty replacement would not be possible - but Hard Disk Sentinel reported the high number of problems which allowed time to perform a backup of important data.

Recommendations

Use Disk menu -> Surface Test -> Reinitialise Disk Surface test to improve the stability of the hard disk by forcing re-allocation of sectors (making them permanenty bad, to prevent further use). If the amount of problems is relatively low, this helps and the hard disk can be used - even if the health is not 100%. This is possible only if running the Disk menu -> Surface Test -> Read test shows no errors and reports all blocks with green, indicating that the disk surface is now fixed and stable.

However, if the health is very low and if the hard disk surface test ( Disk menu -> Surface Test -> Read test ) reports yellow and red blocks even after Disk menu -> Surface Test -> Reinitialise Disk Surface test (especially if Reinitialise Disk Surface test started two or more times), the hard disk surface is still considered instable and should not contain sensitive data as it can be lost any time. This kind of problem can't be repaired. The only way to use the hard disk for secondary storage would be if one or more partition(s) created for data area(s) showing only light green blocks. However, if the problems affect excessively high part of the hard disk surface (as in this example) the hard disk should not be used at all, even for secondary storage as it acts as a "time-bomb".