{
  "schema_version": 1,
  "source_url": "https://f001.backblazeb2.com/file/Backblaze-Hard-Drive-Data/data_Q4_2025.zip",
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  "generator_sha256": "761a1503b4451d93426b2ffc1355dad14cf5f46506dcbcedb23c2f8191cad004",
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  "generated_at": "2026-10-11T01:23:27.352516+00:00",
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  "last": "data_Q4_2025/2025-12-31.csv",
  "selection": "capacity_bytes >= 3e12; failed=all failure=1 rows in Q4; survivor=December 31 failure=0 rows; capacity alone is not a universal media classifier",
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    "ALL|failed|5|missing": 19,
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    "Seagate|failed|mask|00000": 18,
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  "totals": {
    "below_3tb_rows": 365931,
    "eligible_drive_days": 30575777,
    "raw_rows": 30941708,
    "unique_failed_drives": 945,
    "unique_december31_nonfailed_drives": 334842,
    "cohort_overlap": 0
  },
  "limits": [
    "Failure-day association, not advance prediction or causal inference.",
    "No-value and partial-value records cannot establish five zero attributes.",
    "Model-prefix grouping is not a device capability or vendor-encoding validation.",
    "No parsing of packed counters, history imputation or collection-failure diagnosis.",
    "December 31 nonfailed drives are a snapshot, not all nonfailed drives exposed in Q4."
  ]
}