{
  "slug": "diskseen",
  "term": "DiskSeen",
  "aliases": [],
  "definition": "DiskSeen is a research prefetching scheme that uses logical block layout and access history to predict disk reads.",
  "note": "It supplements file-level prefetching, including cross-file and metadata access opportunities. Logical block numbers are not a map of exact physical geometry. [diskseen07]\n\nDemand accesses update its history; speculative fetches alone do not count as demand. [diskseen07]",
  "status": "research",
  "advantages": [],
  "limitations": [
    {
      "text": "The prototype lacks adaptive prefetch throttling and can suffer from stale predictions and excessive history-table memory.",
      "citationIds": [
        "diskseen07"
      ]
    }
  ],
  "related": [
    "dulo",
    "table-based-prefetching",
    "prefetch-wastage",
    "readahead"
  ],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-11-09",
  "citations": [
    {
      "id": "diskseen07",
      "label": "Ding et al., USENIX ATC 2007",
      "title": "Ding et al. DiskSeen: Exploiting Disk Layout and Access History to Enhance I/O Prefetch. USENIX ATC 2007, pp. 261-274; sections 2-4.",
      "url": "https://www.usenix.org/event/usenix07/tech/full_papers/ding/ding.pdf",
      "accessed": "2026-11-09"
    },
    {
      "id": "hesela-layout",
      "title": "Hesela: layout-aware prefetching and the cost of a wrong prediction",
      "url": "https://hesela.com/analyses/o-direct-alignment-by-kernel/#disk-layout-prefetch",
      "accessed": "2026-11-09"
    }
  ],
  "provenance": [
    "Historical single-HDD Linux 2.6.11/ext3 prototype; no modern SSD performance inference or replication."
  ]
}