{
  "status": "shipping",
  "advantages": [],
  "limitations": [],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-10-16",
  "slug": "power-on-hours",
  "term": "Power-on hours",
  "aliases": [
    "POH",
    "accumulated power-on time"
  ],
  "definition": "Power-on hours is accumulated powered-operation time reported for a device, interpreted according to that device's counter and interface semantics.",
  "note": "This is not time since purchase, host uptime or a measure of write endurance. A self-test timestamp records an earlier test, not necessarily current runtime. Raw time fields may use units other than hours; missing telemetry is unknown, not zero. [smartctl] Cisco's affected-drive procedure requires fresh collection and distinguishes accumulated minutes from hours. [ciscofn]",
  "related": [
    "drive-firmware-revision",
    "smart",
    "smart-raw-value",
    "drive-day"
  ],
  "citations": [
    {
      "id": "ciscofn",
      "title": "Cisco FN70545, revision 2.0: 40,000-hour failure, C405 firmware and runtime collection",
      "url": "https://www.cisco.com/c/en/us/support/docs/field-notices/705/fn70545.html",
      "accessed": "2026-10-16"
    },
    {
      "id": "smartctl",
      "title": "smartmontools 7.5 smartctl manual: self-test timestamps, background-scan runtime and raw time formats",
      "url": "https://github.com/smartmontools/smartmontools/blob/RELEASE_7_5/smartmontools/smartctl.8.in",
      "accessed": "2026-10-16"
    }
  ]
}