{
  "556": {
    "ind1": " ",
    "ind2": " ",
    "subfields": [
      {
        "a": "BASIC reference. 3rd ed. Boca Raton, Fl. : IBM, c1984. (Personal computer hardware reference library); 6361132."
      },
      {
        "z": "drop isbn"
      }
    ]
  }
}

Normalized MARC:

{
  "500": {
    "ind1": " ",
    "ind2": " ",
    "subfields": [
      {
        "a": "BASIC reference. 3rd ed. Boca Raton, Fl. : IBM, c1984. (Personal computer hardware reference library); 6361132."
      }
    ]
  }
}

JSON-LD

{
  "mainEntity": {
    "hasNote": [
      {
        "@type": "Note",
        "label": "BASIC reference. 3rd ed. Boca Raton, Fl. : IBM, c1984. (Personal computer hardware reference library); 6361132."
      }
    ]
  }
}