{
  "slug": "nand-open-block",
  "term": "Open NAND block",
  "aliases": [
    "partially programmed NAND block"
  ],
  "definition": "An open NAND block is a partially programmed erase block whose remaining pages have not yet completed programming.",
  "note": "Calibration: A page group may span writes made before and after a programming pause. Its pages then have different retention or read-disturb histories, so shared read-voltage offsets can mismatch some pages. [irps2020]\n\nBoundary: This is an internal NAND condition, not an NVMe open-zone state or a measure of filesystem free space.",
  "status": "unknown",
  "advantages": [],
  "limitations": [],
  "related": [
    "qlc",
    "qlc-ssd",
    "nand-erase-block",
    "read-retry",
    "data-retention",
    "read-disturb"
  ],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "citations": [
    {
      "id": "irps2020",
      "title": "Papandreou et al. - Open Block Characterization and Read Voltage Calibration of 3D QLC NAND Flash, IRPS 2020, Sections III-IV, Figures 5-9",
      "url": "https://doi.org/10.1109/IRPS45951.2020.9129620",
      "accessed": "2026-10-16"
    }
  ],
  "updated": "2026-10-16",
  "provenance": [
    "IRPS 2020 reports laboratory QLC characterization, not a fleet failure rate. [irps2020]",
    "Chip identities and sample count are not specified; P/E cycles are normalized. [irps2020]"
  ]
}