Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor
using recording by magnetic means; or other means for magnetisation or demagnetisation of a record carrier, e.g. light induced spin magnetisation; Demagnetisation by thermal or stress means in the presence or not of an orienting magnetic field
using a beam of light or a magnetic field for recording; by change of magnetisation; and a beam of light for reproducing,; i.e. magneto-optical,; e.g. light-induced thermomagnetic recording,; spin magnetisation recording,; Kerr; or Faraday; effect reproducing
