{
  "slug": "geckoftl",
  "term": "GeckoFTL",
  "aliases": [],
  "definition": "GeckoFTL is a research flash translation layer that stores page-validity metadata in flash using a buffered, merge-based structure.",
  "note": "Logarithmic Gecko groups invalid-page bits into sorted runs. Queries combine bitmaps newest-first; an erase flag excludes obsolete history from a previous block lifetime. This exchanges cheaper metadata updates for more expensive collection queries. [gecko2016]\n\nAn overwrite can miss the old physical address when its mapping is not cached. The 2015 precursor reconciles delayed invalidations through translation-page reads and cached state before moving victim pages. Its Lazy Gecko garbage collector is distinct from LazyFTL. [gecko2015]",
  "status": "research",
  "advantages": [],
  "limitations": [
    {
      "text": "Evaluation uses EagleTree simulation, not measurements of shipping SSDs. Metadata-only overhead reductions do not describe all device traffic.",
      "citationIds": [
        "gecko2016"
      ]
    }
  ],
  "related": [
    "ftl",
    "garbage-collection",
    "mapping-cache",
    "reverse-mapping-ftl",
    "write-amplification",
    "lazyftl"
  ],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-11-09",
  "citations": [
    {
      "id": "gecko2016",
      "title": "Dayan, Bonnet and Idreos. GeckoFTL: Scalable Flash Translation Techniques For Very Large Flash Devices. SIGMOD 2016, sections 3-5.",
      "url": "https://stratos.seas.harvard.edu/sites/g/files/omnuum4611/files/stratos/files/geckoftl.pdf",
      "accessed": "2026-11-09"
    },
    {
      "id": "gecko2015",
      "title": "Dayan and Bonnet. Garbage Collection Techniques for Flash-Resident Page-Mapping FTLs. arXiv:1504.01666v1, sections 5-6.",
      "url": "https://arxiv.org/abs/1504.01666v1",
      "accessed": "2026-11-09"
    }
  ],
  "provenance": [
    "Source synthesis, not an implementation replication. The 2015 precursor and SIGMOD 2016 paper are distinct versions; their algorithms and evaluation results should not be silently combined."
  ]
}