{
  "slug": "content-aware-ftl",
  "term": "Content-aware FTL",
  "aliases": [
    "CAFTL",
    "Content-aware flash translation layer"
  ],
  "definition": "A content-aware flash translation layer uses data fingerprints to share duplicate pages and suppress redundant writes inside an SSD.",
  "note": "In the CAFTL research design, inline deduplication can avoid programming a duplicate. Background deduplication merges copies already stored; it cannot undo their earlier writes. A bounded fingerprint store and sampling can miss duplicates, so this is best-effort reduction. [caftl]\n\nShared pages use logical-to-virtual-to-physical mapping. Relocation updates the shared virtual mapping, while an exact reference count prevents reclamation until no logical page refers to the physical page. The fingerprint cache's popularity counter is a separate quantity, not the reclamation authority. [caftl]\n\nCRC32 pre-hashing only screens candidates before the design's SHA-1 fingerprint comparison; CRC equality alone does not authorize sharing. The historical SHA-1 assumption is not a current security recommendation. [caftl] [nist-hash]",
  "status": "research",
  "advantages": [],
  "limitations": [
    {
      "text": "Deduplication savings do not by themselves give total device write amplification or prove power-loss safety.",
      "citationIds": [
        "caftl"
      ]
    }
  ],
  "related": [
    "ftl",
    "deduplication",
    "write-amplification",
    "hash-collision",
    "garbage-collection",
    "mapping-cache"
  ],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "citations": [
    {
      "id": "caftl",
      "title": "Chen, Luo and Zhang. CAFTL: A Content-Aware Flash Translation Layer Enhancing the Lifespan of Flash Memory based Solid State Drives. FAST 2011, sections 3-4.",
      "url": "https://www.usenix.org/legacy/events/fast11/tech/full_papers/Chen.pdf",
      "accessed": "2026-11-08"
    },
    {
      "id": "nist-hash",
      "title": "NIST CSRC. Hash Functions: SHA-1 deprecation and collision resistance.",
      "url": "https://csrc.nist.gov/projects/hash-functions",
      "accessed": "2026-11-08"
    }
  ],
  "updated": "2026-11-08",
  "provenance": [
    "CAFTL was evaluated with 11 workload traces in a DiskSim-based simulator, not a modern SSD endurance trial. Section 3.3.2 assumes capacitor-backed journal flushing. [caftl]"
  ]
}