Caviar Black bad blocks


#1

I have recently installed (four weeks ago) six new WD Black drives and on one system I have been getting freezes and crashes. I have just run drive genius on this drive and it is reporting 5 bad blocks. What action should I take, mask the bad blocks or return to WD.


#2

Welcome,

I’d use DLG DIAG and perform a Write Zeros (low level format), selecting full erase when prompted.  The drive will be tested extensively.  If bad sectors are found, they will be marked bad and new space will be reallocated in their place. If this is not possible, or the test fails, the bad disk(s) should be replaced. 

This is a destructive test.  Please back up your data before proceeding.


#3

Thank you for your response. Do all or most drives have bad blocks from new. If not how are bad blocks created and is there a limit to the number that is acceptable before a replacement is warranted.


#4

Hi,

Drives actually come with a reserve “bank” of unallocated space.  When bad sectors are found or develop, the drives firmware actually attempts to move the data and mark that portion of the disk as unuseable.  Useable space is then remapped or reallocated for use.

Imperfections can actually develop from wear and normal use…  dropping a drive whiles its running (being accessed) can also put a nice divot in the disks surface (thats an extreme example) .  Once the reserve is depleted, and new sectors cannot be reallocated…  the drive is considered to be beyond it’s useable life.   

Bad sectors on a drive are not like bad pixels on a monitor where you get a replacement if 8 or more (industry standard) are exceeded.  This is not a good comparison since a drive sees many many more bad sectors during it’s life.    Hope that helps. :wink: