{
  "slug": "prefix-preserving-crash-consistency",
  "term": "Prefix-preserving crash consistency",
  "aliases": [
    "Prefix-preserving disk model"
  ],
  "definition": "A recovery contract in which surviving updates form a prefix of the specified write order, including all writes covered by the last successful flush.",
  "note": "OPTR defines order at device request receipt and adds request-level atomicity; this is not application submission order or atomicity of an entire multi-request transaction. Its no-barrier usage relaxes durability. [optr]",
  "status": "research",
  "related": [
    "ftl",
    "snapshot-consistent-ftl",
    "torn-write"
  ],
  "advantages": [],
  "limitations": [],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-10-15",
  "citations": [
    {
      "id": "optr",
      "title": "Yun-Sheng Chang and Ren-Shuo Liu. OPTR: Order-Preserving Translation and Recovery Design for SSDs with a Standard Block Device Interface. USENIX ATC 2019, pp. 1009-1024; introduction and sections 3, 5-7.",
      "url": "https://www.usenix.org/system/files/atc19-chang_0.pdf",
      "accessed": "2026-10-15"
    },
    {
      "id": "hesela",
      "title": "Hesela: SSD mapping caches and recovery contracts",
      "url": "https://hesela.com/analyses/ssd-mapping-cache-hmb/#crash-contracts",
      "accessed": "2026-10-15"
    }
  ]
}