{
  "slug": "scsi-field-pointer",
  "term": "SCSI field pointer",
  "aliases": [
    "SCSI sense field pointer"
  ],
  "definition": "A SCSI field pointer identifies a byte in the command or parameter data associated with an ILLEGAL REQUEST condition.",
  "note": "For ILLEGAL REQUEST, C/D=1 selects the command descriptor block and C/D=0 selects data parameters. The two-byte pointer is zero-based. BPV=1 adds a bit position; BPV=0 leaves that bit position unavailable, not bit zero. [quantum-fields]\n\nFixed-format sense places this data at bytes 15-17 and gates its interpretation with SKSV. Descriptor format uses type 02h, additional length 06h, with the three sense-key-specific bytes at descriptor offsets 4-6. Other sense keys give these bytes different meanings. [seagate-fields]\n\nA field pointer is separate from the Information field and is not a failing LBA. Keep the original command, received sense length and validity flags. A formatted decoder message is not proof of a conforming response: an offline malformed-descriptor example still prints a pointer in the tested decoder build. [hesela-fields]",
  "status": "shipping",
  "advantages": [],
  "limitations": [
    "The reported byte need not be the byte whose modification resolves the request."
  ],
  "related": [
    "scsi-sense-key",
    "scsi-information-field",
    "scsi-check-condition"
  ],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-11-08",
  "provenance": [
    "The native examples use invented byte buffers and sg3-utils 1.46-3ubuntu4.1, not commands sent to a drive. [hesela-fields]",
    "Rev. M section 2.4.1.1.4.1 prints 01h in one sentence, while its Tables 14 and 17 identify 02h; the pinned decoder also dispatches type 02h. [seagate-fields]"
  ],
  "citations": [
    {
      "id": "quantum-fields",
      "title": "Quantum Scalar i3: Request Sense response and sense-key-specific field definitions",
      "url": "https://qsupport.quantum.com/kb/flare/content/Scalar_i3/docCenter/SCSI/03h.htm",
      "accessed": "2026-11-08"
    },
    {
      "id": "seagate-fields",
      "title": "Seagate SCSI Commands Reference Rev. M, Tables 14, 17-19 and sections 2.4.1.1.4-2.4.1.2",
      "url": "https://www.seagate.com/files/staticfiles/support/docs/manual/Interface%20manuals/100293068m.pdf#page=50",
      "accessed": "2026-11-08"
    },
    {
      "id": "hesela-fields",
      "title": "Hesela: finding the rejected command field, with offline decoder observations",
      "url": "https://hesela.com/analyses/scsi-sense-kernel-log-signatures/#field-pointer",
      "accessed": "2026-11-08"
    }
  ]
}