{
  "slug": "magnetic-core-memory",
  "term": "Magnetic-core memory",
  "aliases": [
    "core memory",
    "ferrite-core memory",
    "ferrite core memory",
    "core store"
  ],
  "definition": "Magnetic-core memory stores binary information in the retained magnetization of ferrite cores selected by electrical currents through wires.",
  "note": "Core can serve as working memory while retaining its magnetic state without continuous power; its system role does not make it volatile. [c1]\n\nIn conventional coincident-current core memory, readout disturbs the selected word and the electronics must restore it. Destructive readout is not a property of every ferrite design: nondestructive-read variants also exist. [c2]\n\nNonvolatility does not guarantee safe interruption of the read/restore sequence. Ricci's NASA survey discusses corruption from electronic malfunction and the protection needed during power failures. [c2]",
  "status": "eol",
  "advantages": [],
  "limitations": [],
  "related": [
    "drum-memory",
    "bubble-memory",
    "byte-addressable-storage"
  ],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "citations": [
    {
      "id": "c1",
      "title": "IBM: World of Numbers (1958), PDF p. 18, Magnetic Cores",
      "url": "https://archive.computerhistory.org/resources/access/text/2023/05/102707549-05-01-acc.pdf",
      "accessed": "2026-10-18"
    },
    {
      "id": "c2",
      "title": "Robert C. Ricci: Present and Future State of the Art in Guidance Computer Memories, NASA TN D-4224 (November 1967), pp. 2-4 and Table I",
      "url": "https://ntrs.nasa.gov/api/citations/19670030990/downloads/19670030990.pdf",
      "accessed": "2026-10-18"
    }
  ],
  "updated": "2026-10-18",
  "provenance": [
    "The NASA report surveys guidance-computer memories; its projections for 1970-1972 are not used here as observed results. [c2]"
  ]
}