Movid Information Technology, Inc.

General Electric Company

Han-Ping D Shieh

Mark H Kryder

Methods and apparatus are provided for recording, erasing and reading elongated magnetic domains on magneto-optic media using laser energy. Recording and erasing can be carried out in the absence of a reversible external magnetic bias field. The preferred magneto-optic media to be used have compensation temperatures higher than about 40.degree. C. Recording and erasing are carried out using either continuously or intermittently energized lasers.

Direct overwrite magneto-optic system for strip erasing and recording

Methods for directly over-writing the binary data value of a bit of digital data, stored in a particular one of a multiplicity of microscopic storage regions of a thin-film magneto-optic recording layer, in the absence of a substantial externally applied bias magnetic field, employ a magnetic material having a compensation temperature a few tens of degrees centigrade above room temperature. A source of energy is energized to heat the particular storage region to a sufficiently high temperature that the self-demagnetization field of the recording layer material inverts the net magnetic moment of that region. Multiple over-writing of the long-term stable stored data values can be provided.

Method and system for erasing previously recorded domains in a

A magneto-optic information storage system is disclosed suitable for compensation point recording in the absence of an external bias field. The pulse of light used to erase imparts less energy than the pulse used to write. Also disclosed is a method for directly overwriting data recorded on a magneto-optic medium by applying lower energy erasing pulses of light and higher energy writing pulses.

Single-head, direct overwrite magneto-optic system and method

Methods for directly over-writing the binary data value of a bit of digital data, stored in a particular one of a multiplicity of microscopic storage regions of a thin-film magneto-optic recording layer, first locate the storage region and non-destructively read the stored data value therefrom, and then compare the recovered value against the data value of an information bit to be stored in the same storage region. If the comparison indicates that no change in the stored data value is required, then the process proceeds to read and compare the next bit of data, from the next associated storage location. If the comparison indicates that a reversal of the magnetic moment of that region is required to store the new data value, a source of energy is energized to heat the particular storage region of a sufficiently high temperature that the self-demagnetization field of the recording layer material inverts the net magnetic moment of that region. Multiple over-writing of the long-term stable stored data values can be provided.

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Pittsburgh, PA, United States of America

Han-Ping D Shieh