{
  "slug": "uncorrectable-bit-error-rate",
  "term": "Uncorrectable bit error rate",
  "aliases": [
    "UBER",
    "uncorrectable bit error ratio"
  ],
  "definition": "Uncorrectable bit error rate is a storage reliability metric that normalizes unrecovered data-error outcomes by a specified bit count after the stated correction and recovery procedures.",
  "note": "State the event unit and denominator: Solidigm's D7-P5810 brief specifies UBER in sectors per bits read. [solidigm-p5810] Cai and colleagues instead normalize codeword failure rate by codeword length in their ECC comparison. [cai2017] Neither convention counts every wrong bit in a failed unit. A specification limit is not an observed fleet rate, and does not by itself establish independent, constant-probability errors.",
  "limitations": [
    {
      "text": "A source's counting convention must accompany its UBER value before comparison or use in a reliability model.",
      "citationIds": [
        "solidigm-p5810",
        "cai2017"
      ]
    }
  ],
  "related": [
    "bit-error-rate",
    "raw-bit-error-rate",
    "error-correcting-code",
    "codeword",
    "ldpc",
    "latent-sector-error"
  ],
  "citations": [
    {
      "id": "solidigm-p5810",
      "title": "Solidigm D7-P5810 product brief, page 3 reliability table and page 4 qualification note.",
      "url": "https://www.solidigm.com/content/dam/solidigm/en/site/products/data-center/product-briefs/d7-5810/documents/solidigm-d7-p5810-product-brief.pdf",
      "accessed": "2026-10-12"
    },
    {
      "id": "cai2017",
      "title": "Cai et al. Error Characterization, Mitigation, and Recovery in Flash Memory Based Solid-State Drives (2017), sections II.C and VI.C.",
      "url": "https://research.ece.cmu.edu/safari/pubs/1706.08642.pdf",
      "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"
    }
  ],
  "status": "shipping",
  "advantages": [],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-10-12"
}