198343 ⎘
Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups - or by different subgroups of group ; 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 and a beam of light for reproducing, e.g. light-induced thermomagnetic recording, Kerr effect reproducing; Disposition or mounting of transducers relative to record carriers with provision for moving or switching or masking the transducers in or out of their operative position; Mechanically moving the transducers Sled type positioners