{
  "slug": "device-configuration-overlay",
  "term": "Device Configuration Overlay (DCO)",
  "aliases": [
    "DCO"
  ],
  "definition": "Device Configuration Overlay is an optional legacy ATA mechanism that can reduce a device's reported capacity and available features.",
  "note": "DCO is a device configuration mechanism, not a partition. The documented drive implementation changes reported features and capacity, including the result of READ NATIVE MAX ADDRESS. That result alone therefore need not reveal the unrestricted capacity. [seagate-dco]\n\nRemoving a capacity restriction is not evidence that data was erased. Do not assume all device erase operations have the same scope: the openSeaChest maintainer distinguishes normal ATA Security Erase from enhanced erase and Sanitize for HPA/DCO. This is a command-scope clarification, not testing of an individual drive. [seagate-erase-scope]\n\nIn the ATA/ATAPI-6 draft, an accepted DEVICE CONFIGURATION FREEZE LOCK blocks configuration changes and DEVICE CONFIGURATION IDENTIFY until power-down; hardware and software resets do not clear it. An aborted identification request alone does not prove DCO is unsupported. [ata6-draft]",
  "status": "unknown",
  "advantages": [],
  "limitations": [
    {
      "text": "Device support and sanitization coverage require device-specific evidence; a feature label does not certify a successful erase.",
      "citationIds": [
        "nist-r2"
      ]
    }
  ],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-10-24",
  "related": [
    "host-protected-area",
    "sata",
    "data-sanitization",
    "secure-erase",
    "accessible-max-address-configuration"
  ],
  "citations": [
    {
      "id": "seagate-dco",
      "title": "Seagate Laptop HDD Product Manual 100772113 Rev. C (2016), section 11.2.3: DCO capacity and READ NATIVE MAX",
      "url": "https://www.seagate.com/www-content/support-content/samsung/internal-products/spinpoint-m-series/en-us/docs/100772113c.pdf",
      "accessed": "2026-10-24"
    },
    {
      "id": "seagate-erase-scope",
      "title": "Seagate openSeaChest maintainer clarification (7 January 2021), discussion 52: HPA/DCO versus AMAC erase scope",
      "url": "https://github.com/Seagate/openSeaChest/discussions/52",
      "accessed": "2026-10-24"
    },
    {
      "id": "nist-r2",
      "title": "NIST SP 800-88 Rev. 2 (2025), Appendix B: device-specific sanitization implementation and uncovered areas",
      "url": "https://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-88r2.pdf",
      "accessed": "2026-10-24"
    },
    {
      "id": "hesela",
      "title": "Hesela: SSD sanitization: why TRIM and a successful command are not enough",
      "url": "https://hesela.com/analyses/ssd-sanitization-trim-evidence/",
      "accessed": "2026-10-24"
    },
    {
      "id": "ata6-draft",
      "title": "T13 ATA/ATAPI-6 working draft 1410D rev. 3a (2001), sections 8.8.2.8 and 8.8.3.6: DCO freeze and identification",
      "url": "https://www.read.seas.harvard.edu/~kohler/class/04f-aos/ref/hardware/ATA-d1410r3a.pdf",
      "accessed": "2026-10-24"
    }
  ]
}