Abstract: A recorder of the present invention includes an optical disk drive section recording data on an optical disk, and a host section transferring data recorded on an arbitrary recording medium to the optical disk drive section to record the data on the optical disk, wherein the optical disk drive section intermittently records the data transferred from the host section on the optical disk.

Abstract: A disk drive apparatus includes: an optical pickup irradiating a laser beam onto an optical disk having one or more recording layers through an objective lens and receiving the laser beam reflected from the optical disk; a driving unit moving the objective lens in an optical axial direction of the laser beam to the optical disk in accordance with a driving signal; an interlayer distance measuring unit measuring interlayer distances of a plurality of recording layers of the optical disk; and a spherical aberration correcting unit obtaining a spherical aberration correction value for correcting a spherical aberration due to the objective lens to one of the recording layers of the optical disk. A spherical aberration correction value to another one of the recording layers is obtained on the basis of the measured interlayer distances and the obtained spherical aberration correction value to the one recording layer.

Abstract: In an optical disk apparatus using an optical disk having groove tracks and land tracks alternately arranged therein and land pre-pits indicating position information defined in the land tracks, the optical disk is irradiated with a light beam and light reflected from the optical disk is received on divisional light-receiving surfaces to generate a light detection signal for each of the light-receiving surfaces. A pre-pit component signal corresponding to the land pre-pits is generated based on the light detection signals. A binarization-level signal is output. A pre-pit detection signal is generated by comparing the pre-pit component signal with the binarization-level signal. The position information is obtained using the pre-pit detection signal. Pulses of the pre-pit detection signal are counted in units of a period that is based on the position information. The signal level of the binarization-level signal is controlled based on the count values.

Abstract: A disk drive apparatus includes: an optical pickup irradiating a laser beam onto an optical disk having one or more recording layers through an objective lens and receiving the laser beam reflected from the optical disk; a driving unit moving the objective lens in an optical axial direction of the laser beam to the optical disk in accordance with a driving signal; an interlayer distance measuring unit measuring interlayer distances of a plurality of recording layers of the optical disk; and a spherical aberration correcting unit obtaining a spherical aberration correction value for correcting a spherical aberration due to the objective lens to one of the recording layers of the optical disk. A spherical aberration correction value to another one of the recording layers is obtained on the basis of the measured interlayer distances and the obtained spherical aberration correction value to the one recording layer.

Abstract: An optical disk device has a unit for counting data read errors from an optical disk and a unit for reducing a playback speed of an optical disk. When a number of data read errors occurring in a predetermined period of time exceeds a predetermined value the playback speed reducing unit reduces the playback speed of the optical disk. As a result, repetition of error detection and consequent reduction in playback speed with each data read command when reading defective sectors of an optical disk can be prevented and the time required for error detection and speed reduction thereby eliminated, greatly improving overall average playback speed.

Abstract: A disk apparatus in which a control unit performs a seek control includes a disk motor which rotates a disk placed at a loaded position in the disk apparatus. A motor driver controls the disk motor such that the disk is rotated by the disk motor at a controlled speed. A read/write head reads information from or writes information to the disk when the disk is rotated by the disk motor at the controlled speed. A head shifting unit shifts the head in a radial direction of the disk to a target location thereof when a seek is performed. A current supply control unit controls current supplied to the disk motor during the seek. In the disk apparatus, the current supply control unit cuts off the current supply to the disk motor for a predetermined period after a start of the seek.

Abstract: A CD-ROM drive is disclosed which is for use with disks having various degrees of spindle hole eccentricity and data track eccentricity. The hole eccentricity of each disk manifests itself during disk rotation as periodic vibration of the disk and, in consequence, periodic departures of the light beam spot from the track to an extent proportional to the speed of disk rotation, whereas the track eccentricity manifests itself during disk rotation as periodic departures of the beam spot from the track to a constant extent regardless of the speed of disk rotation. Therefore, on being loaded into the disk drive, each disk has its hole eccentricity and track eccentricity measured at two different disk eccentricity check speeds in terms of, for example, the amplitude of an eccentricity-caused periodic component of a tracking error signal. The hole eccentricity of the disk is ascertainable by subtracting the eccentricity measurement at the lower check speed from that at the higher check speed.

Abstract: An optical disc apparatus prevents an occurrence of an error in the mirror signal due to a change in a reproducing speed or usage of different kinds of optical discs. A mirror circuit generates a mirror signal by comparing a level of a bottom signal with a level of a reference level signal. The bottom signal is detected from a reflection signal obtained by optically scanning the optical disc. A reference level control circuit generates a reference level control signal based on the reproducing speed. A reference level signal setting circuit sets a level of the reference level signal in accordance with the reference level control signal.