[ale] One possible explanation - Re: 9.10 smart errors

[Brian Pitts]

On 11/02/2009 03:33 PM, Robert Reese wrote:
> 
> My experience with these new massive harddrives is that the magnetic layers' density has gotten so tight that it is easy for a sector to fail.  Furthermore, I believe these drives are coming with many such failed sectors from the factory, and that the manufacturers have significantly 'padded' the sector count to ensure the number of available useful sectors will easily reach the number of sectors required to meet the specified drive size.
> 
> That is, I think manufacturers intentionally make larger harddrives with more bad sectors and label them as smaller drives rather than to make a drive that more closely matches its physical capacity with far less bad sectors.
> 
> Think of it this way: You need a warehouse that is 14,000 square feet.  You can afford $1400 for the lease, which is paltry and laughable.  Someone comes along and offers you a 14,000 sq.ft. facility for the money - with a hitch: the building is actually 20,000'sq total, but 2,500'sq are unusable, and another 3,500'sq need to be left empty in case some areas become unusable (wiring fails, roof blows off, etc.) and the items in those failed areas need to be relocated.  You get your 14,000 usable square foot warehouse for the money... just don't ask a building inspector's opinion.
> 
> Ditto for your SMART tools. Unfortunately, most current tools don't know what is bad from the factory and what went bad.  I can only assume there are tools out there that can compare subsequent scans to a baseline scan.  I also assume there are tools that can access the existing list of bad sectors recorded in the drive's controller.

I though modern consumer hard drives hid their bad sectors from the OS
until they ran out of spare sectors to remap them to. Can anyone confirm
or deny this?

-- 
All the best,
Brian Pitts