I'd like to know whether any sectors on my solid state drive are inaccessible due to

  • the host protected area (HPA)
  • or the device configuration overlay (DCO)

Is there a file in /proc/ I can read or any tool I can use to find out about HPA and DCO?

I'm on Arch Linux 5.9.14.


with hdparm

To find out about the host protected area, use hdparm's -N option, for example

sudo hdparm -N /dev/sda

yields this on my machine:

max sectors   = 1953529856/1953529856, HPA is disabled

With --dco-identify we can find out about the device configuration overlay.

sudo hdparm --dco-identify /dev/sda

Example output:

DCO Checksum verified.
DCO Revision: 0x0002
The following features can be selectively disabled via DCO:
        Transfer modes:
                mdma0 mdma1 mdma2
                udma0 udma1 udma2 udma3 udma4 udma5 udma6
        Real max sectors: 1953529856
        ATA command/feature sets:
                SMART error_log security 48_bit
        SATA command/feature sets:
                interface_power_management SSP

Let's focus on this line:

Real max sectors: 1953529856

Comparing this number with the "max sectors" line of hdparm -N, we can see that there is no sector hidden using DCO:

1953529856 - 1953529856 = 0

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