Hidden Areas - HPA/DCO

The Host Protected Area (HPA) and Device Configuration Overlay (DCO) are hard disk features for hiding sectors of a hard disk from being accessible to the end user.

A typical usage for an HPA is to store boot sector code or diagnostic utilities of the manufacturer. However, it is also know that the HPA can be used for malicious intent including hiding illegal data of interest to forensics investigators.

The DCO feature was proposed to allow system vendors to purchase hard disks of different sizes, but setting the hard disk capacity of each disk to the same size. Again, this allows for hiding of data within the hidden sectors.

DiskCheckup allows the user to detect the presence and set the new size of HPA/DCO hidden areas.

Modify HPA/DCO
Check this box to change the size of the HPA/DCO areas

Max User LBA
The maximum addressable sector by the user. This determines the capacity reported by the disk to the system. Changing this value changes the size of the HPA.

Max Native LBA
The maximum addressable sector allowed by the disk. Changing this value changes the size of the DCO.

Max Disk LBA
The maximum addressable sector of the physical disk. This value cannot be changed.

HPA Size
The size of the area between the Max User LBA and Max Native LBA

DCO Size
The size of the area between the Max Native LBA and Max Disk LBA

Depending on the hard disk, the HPA/DCO areas may be locked and therefore cannot be changed. This is indicated by "N/A" for the appropriate fields.

Note: You will need to detach/re-attach the hard disk (or reboot) after your changes to allow the system to retrieve the new capacity of the disk.