{
  "slug": "head-slap",
  "term": "Head slap",
  "aliases": [
    "head-slap"
  ],
  "definition": "Head slap is a head-disk contact mechanism in which an HDD slider separates from the disk and then snaps back into it.",
  "note": "Li and Bogy identify this mechanism in their coupled structural and air-bearing simulation, distinct from long-pulse loading that overcomes a still-positive bearing force [shock]. Residual vibration can cause contact after the pulse ends. It is a mechanism, not a synonym for every head crash, a SMART counter or a universal shock threshold.",
  "status": "unknown",
  "related": [
    "head-disk-interface",
    "flying-height"
  ],
  "citations": [
    {
      "id": "shock",
      "title": "Li and Bogy: Operational Shock Failure Mechanisms in Hard Disk Drives, CML report 13009, sections 4.1-4.2 and 5",
      "url": "https://cml.berkeley.edu/wp-content/uploads/blue-reports/13009.pdf",
      "accessed": "2026-10-15"
    },
    {
      "id": "analysis",
      "title": "Hesela: HDD mechanical faults, evidence and diagnostic limits",
      "url": "https://hesela.com/analyses/hdd-mechanical-failure-points/",
      "accessed": "2026-10-15"
    }
  ],
  "advantages": [],
  "limitations": [],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-10-15"
}