Abstract: An apparatus comprises a spindle to rotate a magnetic recording medium and a magnetic field generator to expose a track of the medium to a DC magnetic field. The magnetic field generator is configured to saturate the track during an erase mode and reverse the DC magnetic field impinging the track during a writing mode. A laser arrangement heats the track during the erase mode and, during the writing mode, heats the track while the track is exposed to the reversed DC magnetic field so as to write a magnetic pattern thereon. A reader reads the magnetic pattern and generates a read signal. A processor is coupled to the reader and configured to determine an anisotropy parameter using the read signal. The apparatus can further comprise a Kerr sensor that generates a Kerr signal using the magnetic pattern.

Abstract: Provided are a method and an apparatus to prevent reproducibility of data with respect to an optical information storage medium. The method includes recording patterns with respect to the optical information storage medium using irradiated light so as prevent reproduction of the data. The patterns may cause an error or a malfunction when attempting to access the data of the optical information storage medium so as to prevent the reproduction of the data.

Abstract: An optical recording medium is provided with at least a substrate, light absorbing and heat generating parts each of which absorbs light and generates heat, and recording parts, and each of the recording parts are formed between two recording tracks.

Abstract: A method to erase data stored on an erasable optical recording system is provided. The optical recording system includes a laser IO head having a blue-light laser, a red-light laser, and an infrared-light laser writing data on the blu-ray disc, the DVD disc, and CD disc, respectively. The method includes indexing the infrared-light laser of the laser IO head one track of the blu-ray disc every 0.4 revolutions after first 0.8 revolutions, to erase the data stored on the blu-ray disc.

Abstract: There are provided an optical disk, a magneto-optical disk, a disk apparatus therefor, and a data recording method which can provide improved recording/reproducing characteristics and record durability without linear velocity dependency even if the data access speed is increased by increasing the channel clock frequency. In a disk device for recording data on an optical disk by using a phase change recording scheme, erasing means for erasing data on the optical disk, and recording means for recording other data on the optical disk after the data is erased are provided.

Abstract: A magneto-optical recording or reproducing device having an information erasing means for erasing information or data recorded on a magneto-optical recording medium. According to the invention, the information erasing means comprises an erasing magnet having a field strength sufficient to initialize the magneto-optical recording medium without the assistance of a laser and/or an optical scanning device.

Abstract: When carrying out magnetization, annealing, and initialization of a recording film by applying a laser beam to the recording film while rotating an optical recording medium 10 by a motor 11, light of a strong visible-light lamp 15 is projected as parallel light to a reflecting mirror 14 via a lens 16 so as to apply light reflected by the reflecting mirror 14 to an area wider than a spot of the laser beam on the medium 10 for heating. At that time, a control unit 18 controls an intensity of the strong visible-light lamp 15 to raise a temperature of the medium 10 to a temperature of 80° C. or higher and a softening point of a substrate or lower, for example.

Abstract: It is an object of the present invention to provide a method for recording information in an optical recording medium with a good direct overwriting characteristic. The method for recording information in an optical recording medium according to the present invention forms record marks in a recording layer containing a phase change material by modulating the power of a laser beam between a plurality of power levels including a recording power Pw, an erasing power Pe and ground power Pb. The erasing power Pe is set to a level within a region where a reflection coefficient of a region between neighboring record marks approaches a reflection coefficient of the record mark as the erasing power Pe increases. As a result, a good overwriting characteristic can be obtained when data are recorded at a high linear velocity.

Abstract: A CD-ROM has an obscurable section wherein exists a photosensitive mask material layer or constituent operative to alter the optical properties of areas subjected to prolonged exposure to the CD-ROM read laser radiation. Digital information stored on a CD-ROM is made accessible by use of a password, which is generated from user machine unique information, and which is written on the CD-ROM via selective exposure of the CD-ROM to the radiation used to read the CD-ROM.

Abstract: There are provided an optical disk, a magneto-optical disk, a disk apparatus therefor, and a data recording method which can provide improved recording/reproducing characteristics and record durability without linear velocity dependency even if the data access speed is increased by increasing the channel clock frequency. In a disk device for recording data on an optical disk by using a phase change recording scheme, erasing means for erasing data on the optical disk, and recording means for recording other data on the optical disk after the data is erased are provided.

Abstract: A method for performing full optimization of most of the files on a volume in accordance with a composed optimization plan, is performed, including the separation of less frequently accessed files from those whose number or location of clusters is being more frequently modified by user applications. Optimization does not continue indefinitely—it reaches a final state even if a small percentage of its file data is still out of place under the optimization plan and therefore not in the planned part of a plan-defined, Placed Files Area. Each time a Push of out-of-place file data is attempted, or a Pull of file data into a correspondingly planned free space within the Placed Files Area is attempted, a copy of the current volume bitmap is made in order to determine what is the largest free space currently available in the Placed Files Area. Once determined, the size of the largest free space is compared to the size of the largest out-of-place range of corresponding clusters in the Placed Files Area.

Abstract: An apparatus marks files within a content archive. The content archive contains a database that has a plurality of content files. The content archive also contains a plurality of entries or records. Each of the entries corresponds to a distinct one of the plurality of content files. Each of the entries also includes a played field that is automatically set when the corresponding content file has been played. The content archive also includes a writing module that is configured to record a new content file to the content archive and, if insufficient space is available, to overwrite a content file for which the played fields are set. According to one aspect, the plurality of entries also includes an entry corresponding to an overwritten content file previously contained within the database that is no longer contained within the database. The database may contain references to content no longer in the database.

Abstract: When carrying out magnetization, annealing, and initialization of a recording film by applying a laser beam to the recording film while rotating an optical recording medium 10 by a motor 11, light of a strong visible-light lamp 15 is projected as parallel light to a reflecting mirror 14 via a lens 16 so as to apply light reflected by the reflecting mirror 14 to an area wider than a spot of the laser beam on the medium 10 for heating. At that time, a control unit 18 controls an intensity of the strong visible-light lamp 15 to raise a temperature of the medium 10 to a temperature of 80° C. or higher and a softening point of a substrate or lower, for example.

Abstract: A magneto-optical recording and reproduction device includes an optical pickup for irradiating a magneto-optical disk with a laser beam for performing at least one of information recording to a magneto-optical disk, information reproduction from the magneto-optical disk, and information erasure from the magneto-optical disk; a magnetic head for providing a magnetic field to a position of the magneto-optical disk irradiated with the laser beam for performing at least one of the information recording and the information erasure, the magnetic head being located opposite to the optical pickup with respect to the magneto-optical disk where the magneto-optical disk is mounted on the magneto-optical recording and reproduction device; a housing for accommodating the optical pickup; a guide shaft for moving the housing; a suspension for supporting the magnetic head; and an arm for connecting the suspension and the housing.

Abstract: There are provided an optical disk, a magneto-optical disk, a disk apparatus therefor, and a data recording method which can provide improved recording/reproducing characteristics and record durability without linear velocity dependency even if the data access speed is increased by increasing the channel clock frequency. In a disk device for recording data on an optical disk by using a phase change recording scheme, erasing means for erasing data on the optical disk, and recording means for recording other data on the optical disk after the data is erased are provided.

Abstract: A magneto-optical recording and reproduction device includes an optical pickup for irradiating a magneto-optical disk with a laser beam for performing at least one of information recording to a magneto-optical disk, information reproduction from the magneto-optical disk, and information erasure from the magneto-optical disk; a magnetic head for providing a magnetic field to a position of the magneto-optical disk irradiated with the laser beam for performing at least one of the information recording and the information erasure, the magnetic head being located opposite to the optical pickup with respect to the magneto-optical disk where the magneto-optical disk is mounted on the magneto-optical recording and reproduction device; a housing for accommodating the optical pickup; a guide shaft for moving the housing; a suspension for supporting the magnetic head; and an arm for connecting the suspension and the housing.