{
  "slug": "accessible-max-address-configuration",
  "term": "Accessible Max Address Configuration (AMAC)",
  "aliases": [
    "AMAC"
  ],
  "definition": "Accessible Max Address Configuration is an optional ATA feature set for discovering a device's native maximum LBA and controlling its accessible maximum LBA.",
  "note": "In ACS-3 revision 5, GET reports the native maximum and SET controls the accessible maximum. Once excluded addresses become accessible again, their contents are indeterminate. [acs3-amac]\n\nIn ACS-3 revision 5, a successful SET prevents another SET before power-on reset. FREEZE also blocks later SET requests until power-on reset, and hardware/software resets do not clear that freeze. A refusal alone does not prove an explicit FREEZE was issued. [acs3-amac]\n\nThe native-maximum LBA boundary in Table 91 does not imply identical treatment of reallocated user data. The cited draft excludes it from normal erase and includes it in enhanced erase. [acs3-amac]",
  "status": "unknown",
  "advantages": [],
  "limitations": [
    {
      "text": "Increasing the accessible range does not guarantee recovery of earlier contents.",
      "citationIds": [
        "acs3-amac"
      ]
    }
  ],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-10-24",
  "related": [
    "host-protected-area",
    "device-configuration-overlay",
    "sata",
    "data-sanitization",
    "secure-erase"
  ],
  "citations": [
    {
      "id": "acs3-amac",
      "title": "T13 ACS-3 draft 2161-D rev. 5 (28 October 2013), Table 6; sections 4.5 and 7.2; section 7.39 Table 91",
      "url": "https://read.seas.harvard.edu/cs161/2020/pdf/ata-atapi-8.pdf",
      "accessed": "2026-10-24"
    },
    {
      "id": "seagate-ata-security-2026",
      "title": "Seagate openSeaChest ATA Security Feature guide (last edited 11 February 2026), Security Erase",
      "url": "https://github.com/Seagate/openSeaChest/wiki/ATA-Security-Feature#security-erase",
      "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": "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"
    }
  ],
  "provenance": [
    "ACS-3 revision 5 is a historical working draft, not a current approved standard. [acs3-amac]",
    "The 2021 clarification and 2026 guide disagree on normal-mode ATA Security Erase coverage with AMAC; this conflict remains unresolved. Use the applicable command-set revision and model/firmware evidence. [seagate-erase-scope] [seagate-ata-security-2026]"
  ]
}