Abstract: A control circuit for use in a magneto-optic data recording system is disclosed. The control circuitry includes proportional-integral-derivative (PID) circuitry for controlling the rotation position of a permanent magnet. Acceleration circuity is used in controlling the rotational movement of the permanent magnet. The outputs from the PID circuitry and the acceleration circuitry are selectively applied to drive circuity using a switch. The drive circuity supplies current to actuators for moving or controlling the position of the permanent magnet.

Abstract: For magneto-optic data recording, permanent magnets are used to produce a magnetic field with a variable field strength. The field strength is varied by controlled rotation of the magnets about their longitudinal axis, which also allows inversion of the direction of the magnetic field. The magnets are oriented such that their combined fields produce a resultant force continuously substantially perpendicular to the recording medium despite rotation of the magnets.

Abstract: A magneto-optic data recording system and actuating device therefor comprises a permanent magnet mounted adjacent to a magneto-optic disk medium. The permanent magnet is rotatable about its longitudinal axis to change the polarity of the magnetic field which supplied to the medium. Rotation of the magnet is achieved by activation of electromagnet actuators located laterally adjacent to the permanent magnet. Rotation of the magnet through 180.degree. is preferably achieved within less than 1 period of revolution of the disk, preferably less than 1/2 the period of revolution of the disk.