Fujitsu Corporation

Yoshiyuki Nanba

Shigenori Yanagi

Akira Minami

Masaharu Moritsugu

Miyozo Maeda

Takehiko Numata

Hiroshi Kumita

A storage medium stores information on a plurality of tracks formed thereon, each of the tracks being divided into a plurality of sectors. The storage medium includes a physically formed sector beginning identifier provided at a leading portion of each sector, and an information storing portion. The information storing portion, another sector address portion at the trailing end of the information storing portion, includes at least one sector address portion at a leading end of the information storing portion, another sector address portion at the trailing end of the information storing portion, and a data portion provided between the two sector address portions.

Optical storage medium in which sector address information is recorded using MSR techniques

A magnetooptic recording medium has at least a recording layer for recording data and a reproducing layer for reproducing the data recorded in the recording layer onto a substrate and reproduces the data by setting a proper reproducing laser power upon reproduction. According to the magnetooptic recording medium, magnetizing directions of a buffer area, a sector address area, and a gap area which are sandwiched between data areas in which the data is recorded are uniformly magnetized in the recording direction.

Magneto-optical recording apparatus having recovery processing unit

Magneto-optical storage medium having data in uniform magnetized recording direction

An optical storage medium processing method where a high power process is conducted upon the power adjusting area of the optical storage medium (which is used to perform optical beam power adjustment) by repeatedly conducting information recording by repeatedly radiating the optical beam at a power that is higher than that used for normal recording or erasing operations. The present invention enables highly reliable high density recording through accurate control of the laser power during the recording operation, in each area of the optical storage medium, regardless of the frequency of write and erase operations performed on each area.

High power controlling system for magneto-optical storage system

A calibration processing unit is provided, a reproducing operation of an optical storage medium by a reproducing unit is executed while changing a reproducing magnetic field and a reproducing laser power, a reproducible state is measured, and a set of best values of the reproducing magnetic field and the reproducing laser power which are used in the reproducing unit are determined on the basis of the measurement result. The calibration processing unit increases the reproducing magnetic field in a state where the reproducing laser power is fixed. When the reproducible state is not obtained, the measurement of the reproducible state due to the increase in reproducing magnetic field is repeated while increasing the reproducing laser power step by step. The reproducible state can be also measured while alternately increasing the reproducing laser power and the reproducing magnetic field.

Optical storage apparatus and recording and reproducing method of optical storage medium

A magnetooptic recording medium having a writing layer and a readout layer on a substrate is used. Data is recorded in the writing layer of the magnetooptic recording medium at a recording density smaller than a diameter of a focal spot of a laser beam. The data recorded in the writing layer of the magnetooptic recording medium at the recording density smaller than the beam diameter is reproduced by setting a reproducing laser power to a proper value. A reproduction laser power calibrating module executes the reproducing operation for calibration of the magnetooptic recording medium, thereby deciding the optimum value of the laser power which is used upon reproduction. For example, the reproduction laser power calibrating module measures a change in reproduction signal while raising the reproducing laser power by using a predetermined minimum reproducing laser power W0 as an initial value and a value obtained by adding a predetermined value Wc to the reproducing laser power (W) when the reproduction signal doesn't change to the optimum reproducing laser power.

Optical disk apparatus and recording and reproducing method of optical

Marks are recorded on an optical disk which is rotated at a constant rotational speed by laser light which is converged on a substantially circular spot. The pulse width of a recording pulse is set at a sufficiently narrow value and the recording power of the laser light is maintained at a constant value. Marks (corresponding to '1') are recorded on the entire disk surface by the laser light with the same recording pulse width and with the same recording power. The recording pulse width is less than about 30% of the mark interval obtained when they are recorded on the optical disk at the highest density. The recording power is set at the value which produces the maximum reproduction amplitude when said marks are recorded on the optical disk at the highest density.

Growing community of inventors

Kawasaki, Japan

Yoshiyuki Nanba