Reallocated Sector Count

[keithht]

Hi, I have a USB external drive which in CrystalDiskInfo is reporting as bad.
Its Reallocated Sector Count entry reads Current: 1 - Worst: 1 - Threshold: 10, now I understand this drive to be buggered and am not using it but I want to know 1 what?, 10 what?, even reading Wikipedia doesn't explain these figures basically just says disc is buggered replace it.
Is the 1 a count of the damaged sectors or a count of sectors available to replace damaged ones and what is the threshold? is it a do not exceed limit or what?, someone must know.

 

[fzabkar]

The raw value usually indicates the actual number of reallocated sectors.

The Current, Worst and Threshold figures are "normalised" values that can be thought of as health percentages. If a drive has no bad sectors, then it gets a score of 100. As defects begin to develop, then the health score falls. When the attribute value falls below the threshold, the drive is considered to have failed SMART.

Different brands and models will have different numbers of spare sectors. For example, some WD models only allow about 500 reallocations before the drive is considered to have failed, while some Seagate models allow 2500. This figure may also depend on the capacity of the drive. For example, a 3TB drive may allow for 3 times as many bad sectors as a 1TB drive. In a typical Seagate model, a drive may lose 1 point from its Current value for every 40 bad sectors. In such a case, a drive with a Current value of 97 will have at least 120 bad sectors.

 

[Fire_Moose]

I have a raw value of 29 on my new/used Seagate 750es. Would this be a fairly safe drive knowing a HDD can go bad at any time?

 

[fzabkar]

I don't trust current models as much as the older ones. My 40GB Seagate has been holding steady at 50 or so reallocated sectors for a couple of years but I doubt that modern drives would last so long. I would keep watching that SMART attribute and be ready to replace the drive.