{
  "slug": "identity-discrepancy",
  "term": "Identity discrepancy",
  "aliases": [],
  "definition": "An identity discrepancy is a disagreement between a stored block's identity and the identity expected by its reader.",
  "note": "A valid checksum can accompany a block belonging elsewhere. Logical identity requires file-system context; physical address identity alone cannot establish freshness after a lost write. [parity]\n\nIn the FAST 2008 field study, identity discrepancies were detected during file-system reads, not RAID-level scrubs. [field]",
  "related": [
    "lost-write",
    "misdirected-write",
    "checksum",
    "parity-inconsistency"
  ],
  "citations": [
    {
      "id": "field",
      "title": "Bairavasundaram et al., An Analysis of Data Corruption in the Storage Stack, FAST 2008, sections 2.2-2.3.",
      "url": "https://www.usenix.org/legacy/events/fast08/tech/full_papers/bairavasundaram/bairavasundaram.pdf",
      "accessed": "2026-10-18"
    },
    {
      "id": "parity",
      "title": "Krioukov et al., Parity Lost and Parity Regained, FAST 2008, sections 4.2-4.6.",
      "url": "https://www.usenix.org/legacy/event/fast08/tech/full_papers/krioukov/krioukov_html/main.html",
      "accessed": "2026-10-18"
    },
    {
      "id": "hesela",
      "title": "Hesela: interpreting the historical field study of silent corruption",
      "url": "https://hesela.com/analyses/silent-corruption-checksum-mismatches/",
      "accessed": "2026-10-18"
    }
  ],
  "provenance": [
    "Historical mechanism terminology; not a claim about every modern filesystem's scrub implementation."
  ],
  "status": "unknown",
  "advantages": [],
  "limitations": [],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-10-18"
}