{
  "slug": "smart-smr-translation",
  "term": "SMaRT (SMR translation)",
  "aliases": [
    "Shingled Magnetic Recording Translation"
  ],
  "definition": "SMaRT is a research SMR translation scheme that combines in-place track updates with relocation and free-space consolidation.",
  "note": "A free following track permits an in-place update. Otherwise SMaRT relocates the updated track and changes its track-level mapping. Garbage collection joins fragmented free regions by moving live tracks, while allocation and migration gradually separate frequently updated data. [smart-paper]\n\nDiskSim experiments used four write-intensive traces with scaled and modulo-trimmed addresses at 30%, 60% and 90% utilization. The low- and medium-utilization advantage over the modeled cache-based comparator narrowed at 90%. These are simulated configurations, not drive-wide operating thresholds. [smart-paper]\n\nThe paper's amplified-write percentage counts write requests triggering foreground GC, not physical bytes divided by host bytes. Its GC-overhead plots also mix migrated tracks for SMaRT with I/O-request counts for the comparator. [smart-paper]",
  "limitations": [
    {
      "text": "Mapping recovery is sketched using persistent checkpoints and per-track backpointers; the performance evaluation does not establish power-loss correctness.",
      "citationIds": [
        "smart-paper"
      ]
    }
  ],
  "related": [
    "shingle-translation-layer",
    "garbage-collection-smr",
    "virtual-guard"
  ],
  "provenance": [
    "Full FAST 2017 paper reviewed, especially sections 4.5 and 5.1-5.5. No benchmark or power-loss experiment was reproduced.",
    "The DiskSim model used a 146 GB drive geometry at 512-byte sectors. Address transformations, prepopulation and utilization are part of the experiment.",
    "Section 5.5.4 explicitly states that the two GC-overhead units are not directly comparable despite sharing an axis."
  ],
  "status": "research",
  "advantages": [],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "citations": [
    {
      "id": "smart-paper",
      "title": "He and Du. SMaRT: An Approach to Shingled Magnetic Recording Translation. FAST 2017, sections 4-5",
      "url": "https://www.usenix.org/system/files/conference/fast17/fast17-he.pdf",
      "accessed": "2026-11-14"
    }
  ],
  "updated": "2026-11-14"
}