{
  "slug": "restricted-copyback",
  "term": "Restricted copyback",
  "aliases": [
    "rCopyback",
    "rcopyback"
  ],
  "definition": "Restricted copyback limits consecutive NAND-internal relocations before requiring an off-chip error-corrected copy.",
  "note": "Hong et al. derive thresholds from wear and retention characterization of 1x-nm MLC NAND. Their rcFTL groups destination blocks by copy count and returns corrected off-chip moves to count zero. This counter records copy history, not cell wear. [hong2018]",
  "status": "research",
  "advantages": [],
  "limitations": [
    {
      "text": "The tested chip population and emulated performance do not specify a safe threshold for another NAND part.",
      "citationIds": [
        "hong2018"
      ]
    }
  ],
  "related": [
    "nand-copyback",
    "program-erase-cycle",
    "data-retention",
    "error-correcting-code",
    "garbage-collection",
    "ftl"
  ],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-10-19",
  "citations": [
    {
      "id": "hong2018",
      "title": "Hong, Kim, Park, Jung and Kim. Revitalizing Copybacks in Modern SSDs: Why and How. Author manuscript arXiv:1810.04603v1, 2018, sections 3-5.",
      "url": "https://arxiv.org/abs/1810.04603v1",
      "accessed": "2026-10-19"
    },
    {
      "id": "hesela-copyback",
      "title": "Hesela: NAND copyback, faster relocation is not fewer writes",
      "url": "https://hesela.com/analyses/nand-copyback-ecc-boundary/",
      "accessed": "2026-10-19"
    }
  ]
}