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Dco and hpa

Device Configuration Overlay (DCO) and Host Protected Area (HPA).



Using hdparm



# hdparm -N /dev/sda

Disabled HPA:

 max sectors   = 1465149168/1465149168, HPA is disabled

Enabled HPA:

 max sectors   = 586070255/586072368, HPA is enabled



# hdparm --dco-identify /dev/sda

Example output:

DCO Revision: 0x0001
The following features can be selectively disabled via DCO:
    Transfer modes:
         mdma0 mdma1 mdma2
         udma0 udma1 udma2 udma3 udma4 udma5 udma6(?)
    Real max sectors: 1465149168
    ATA command/feature sets:
         SMART self_test error_log security HPA 48_bit
         (?): selective_test conveyance_test write_read_verify
         (?): WRITE_UNC_EXT
    SATA command/feature sets:
         (?): NCQ SSP

Removing HPA


Using hdparm


# hdparm -N p586072368 /dev/sdc

(permanently (!) set max visible number of sectors, see example above)

Other Tools

  • TAFT (The ATA Forensics Tool), claims the ability to look at and change the HPA and DCO settings.
  • SAFE-Block, claims the ability to temporarily remove the HPA and remove the DCO and later return it to its original state.
  • HDD Capacity Restore, a reportedly Free utility that removed the DCO (to give you more storage for your hard drive!)
  • Tableau TD1 can remove the HPA and DCO.