Disks

Disk               User Addressable                        Host        Device 
Firmware           Data Area                               Protected   Configuration
Area              (Partition table, partitions)            Area (HPA)  Overlay (DCO)
-n ---- | ---------------------------------------------- | -----------| ------------ n+

• Firmware area
  • firmware code
• UADA
  • Visible storage space for OS
• HPA
  • Known by BIOS, recovery partition and diagnosis tools
• DCO
  • Used by manufacturer for configuration
• HDD
  • No deletion, blocks(?) marked as deleted

• SSD
  • Deleted on block level
  • Wear Leveling, TRIM,
  • HPA/DCO can be enabled (?) https://www.thomas-krenn.com/en/wiki/SSD_Over-provisioning_using_hdparm