{
  "slug": "raw-bit-error-rate",
  "term": "Raw bit error rate",
  "aliases": [
    "RBER",
    "raw bit error ratio"
  ],
  "definition": "Raw bit error rate is the number of erroneous bits divided by the total bits read at a specified measurement point before error correction.",
  "note": "RBER includes errors that correction subsequently repairs. Report sensing conditions, the observation interval and the actual counters. The FAST 2016 first-generation devices recorded only the worst-chunk count among 16 chunks per page: the full error count lies between that count and 16 times it, so the multiplier is a bound, not a calibration. Across-drive percentiles do not reveal the within-codeword error distribution. [schroeder2016] BER comparisons require the same measurement boundary. [snia-ber]",
  "limitations": [
    {
      "text": "RBER alone is not a universal predictor of uncorrectable errors; the FAST 2016 Google fleet study found it was not predictive in that population.",
      "citationIds": [
        "schroeder2016"
      ]
    }
  ],
  "related": [
    "bit-error-rate",
    "uncorrectable-bit-error-rate",
    "error-correcting-code",
    "codeword",
    "ldpc",
    "read-retry"
  ],
  "citations": [
    {
      "id": "schroeder2016",
      "title": "Schroeder, Lagisetty and Merchant. Flash Reliability in Production: The Expected and the Unexpected. USENIX FAST 2016, sections 4 and 5.2-5.3.",
      "url": "https://www.usenix.org/system/files/conference/fast16/fast16-papers-schroeder.pdf",
      "accessed": "2026-10-12"
    },
    {
      "id": "snia-ber",
      "title": "SNIA Dictionary: bit error rate.",
      "url": "https://www.snia.org/education/online-dictionary/term/bit-error-rate",
      "accessed": "2026-10-12"
    },
    {
      "id": "hesela-ldpc",
      "title": "Hesela: LDPC in NAND, the read cost of confidence.",
      "url": "https://hesela.com/analyses/ldpc-soft-decoding-read-cost/",
      "accessed": "2026-10-12"
    },
    {
      "id": "hesela-rber-aggregation",
      "title": "Hesela: BCH, LDPC and the RBER aggregation trap; synthetic counting example, not fleet measurements.",
      "url": "https://hesela.com/analyses/nand-ecc-bch-vs-ldpc/",
      "accessed": "2026-10-12"
    }
  ],
  "status": "shipping",
  "advantages": [],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-10-12"
}