Abstract: According to one embodiment, a multilayer optical recording medium including a substrate, a guide layer group that is provided on the substrate and has guide layers in which positional information in a radial direction is recorded, and a recording layer group that is provided on the substrate and has recording layers in which information can be recorded. In the recording layer group, positional information of the recording layers associated with the positional information recorded in the guide layers and control information of the optical device where reflected light volumes of the laser beams on the guide layers and the recording layers become maximum at the positions in the radial direction are recorded at the positions in the radial direction of the recording layers.

Abstract: There is provided a skew detection method including supplying reproduction signals, which are respectively reproduced approximately simultaneously from at least two tracks including a first adjacent track and a second adjacent track located on both sides of a main track, to first and second filters, causing a combining unit to combine output signals of the first and second filters with a reproduction signal which is reproduced from the main track approximately simultaneously with the first adjacent track and the second adjacent track so as to cancel crosstalk, causing a coefficient control unit to obtain an error with a target value of the output signal of the combining unit and control coefficients of the first and second filters so as to reduce the error, and detecting a skew of an optical disc from values of coefficients of predetermined taps of the first and second filters.

Abstract: A method for reducing a disturbance associated with repeatable runout associated with a removable disc loaded into a storage system. The method includes, at the storage system: logically partitioning the removable disc into sectors; for each of the sectors, obtaining a corresponding profile of repeatable runout contained in the sector; and applying a runout control algorithm to each of the sectors to generate a repeatable runout control (RROC) waveform that is usable to suppress the repeatable runout in the sector as indicated by the profile corresponding to the sector. The method also includes, at the storage system: assembling each RROC waveform to generate a single RROC waveform that is useable to suppress repeatable runout as contained in an entire revolution of the removable disc; and storing, in a memory, the single RROC waveform.

Abstract: The present invention realizes reduction of position information demodulation errors caused by the eccentricity of the magnetic disk and improvement of position signal detection accuracy, as well as enabling quick eccentricity clock correction for arbitrary clock frequencies. An inspection device in accordance with the present invention comprises: a servo demodulation unit which demodulates servo information; a PLL clock generating unit which generates a reference clock and supplies the reference clock to the servo demodulation unit; and a tester control unit. The PLL clock generating unit includes an eccentricity correction circuit for correcting the frequency of the reference clock depending on the eccentricity of the magnetic disk. The tester control unit generates correction data for correcting the frequency of the reference clock, multiplies the correction data by the inverse of a transfer function of the PLL clock generating unit, and supplies the product to the eccentricity correction circuit.

Abstract: An unbalanced disc determining apparatus is provided. The unbalanced disc determining apparatus includes a noise reduction unit configured to reduce noise components of a center error signal obtained from a signal configured to detect light reflected by a disc revolved by a spindle motor, and a determination unit configured to determine whether the revolving disc is unbalanced by determining whether the center error signal of which noise is reduced exceeds a reference value.

Abstract: A method of designating a disk recording capacity and an optical disk recording apparatus using the method, where a maximum recording capacity is designated by measuring an external disturbance for disk regions. The method of designating a disk recording capacity includes: partitioning a disk into a plurality of disk regions, and measuring external disturbance at the disk regions; setting a disk speed based on the measured external disturbance, and designating disk regions excluding the disk regions where the external disturbance is measured as recordable disk regions; and calculating a maximum disk recording capacity based on the designated recordable disk regions.

Abstract: A method of recording a temporary defect list on a write-once recording medium, a method of reproducing the temporary defect list, an apparatus for recording and/or reproducing the temporary defect list, and the write-once recording medium. The method of recording a temporary defect list for defect management on a write-once recording medium includes recording the temporary defect list, which is created while data is recorded on the write-once recording medium, in at least one cluster of the write-once recording medium, and verifying if a defect is generated in the at least one cluster. Then, the method includes re-recording data originally recorded in a defective cluster in another cluster, and recording pointer information, which indicates a location of the at least one cluster where the temporary defect list is recorded, on the write-once recording medium.

Abstract: A tilt can be detected highly accurately by minimizing the tilt detection error. An optical head includes: an objective lens for converging a light beam from a light source onto an optical disc; a photodetector section receiving the beam, reflected from the disc, at divided areas on its photodetection plane and outputting light detection signals from those areas; and a tilt detecting section for detecting a relative tilt between the lens and disc based on the detection signals.

Abstract: A storage system includes a first buffer configured to store a first repeatable runout profile (RRP) for a sector of a rotating storage medium. A second buffer is configured to store a second RRP for the sector. A controller: controls a servo of the rotating storage medium based on the first RRP during a first revolution of the rotating storage medium; and learns the second RRP (i) while operating in a track-following mode, and (ii) during the first revolution. The controller ceases learning of the second RRP when one of (i) the controller is operating in a seek mode and (ii) the rotating storage medium is in an off-track state. Subsequent to the first revolution of the rotating storage medium and based on whether the learning of the second RRP was stopped during the first revolution, the controller replaces the first RRP with the second RRP in the first buffer.

Abstract: A disk drive determines, from eccentric amounts of individual prescribed rotation phases for one round of an optical disk 1, a rotation phase range in which a lens shift amount after tracking pulling-in of an object lens constituting an optical pickup 3 does not exceed a movable range of the object lens in a preset tracking direction, sets the rotation phase range as a tracking pulling-in range, and carries out tracking pulling-in of the optical pickup 3 while the rotation phase of the optical disk 1 is placed within the tracking pulling-in range.

Abstract: An optical disc device capable of preventing a current larger than prescribed in specifications from flowing by measuring amounts of variation in drive signals of the actuator or the spindle motor, and in view of a correlation between those amounts of variation in the drive signals and the amount of current, changing the servo control system characteristics according to measured amounts of variation, and setting a limit to the level of drive signals.

Abstract: An optical disc apparatus for performing both the operation of writing data on an optical disc and the operation of reading data that is stored on the optical disc includes a motor for rotating the optical disc, an optical pickup, which irradiates the optical disc with a light beam and detects the light that has been reflected from the optical disc, an evaluation section for obtaining an indicative parameter of the distortion of a signal waveform representing the light reflected from a data stored part on the optical disc while the optical disc is being rotated by the motor, and a control section for changing the number of revolutions of the optical disc Per unit time if a variation in the indicative parameter of the distortion per rotation of the optical disc exceeds a threshold value while the optical disc is being rotated by the motor.

Abstract: The present invention can promptly start the tracking control. According to an embodiment of the present invention, after making it possible to discriminate the groove G and land L by the initial drive for the objective lens, the servo control and brake control are executed under an optimum condition when the objective lens is initially driven to the inner circumference direction to be outer eccentricity where a spot Pt is easily pulled in so as to pull in the spot Pt and start tracking control, and, in case the TR control error is raised when pulling in the spot Pt in an eccentricity speed minimum region AR1 for the first time, assuming that the eccentricity speed minimum region AR1 is inner eccentricity, the spot Pt is pulled in at the next eccentricity speed minimum region AR2 in which the eccentricity direction becomes opposite and the tracking control is started.

Abstract: A data recording/reproduction method for performing a data recording/reproduction process on a flexible optical disk by rotating the flexible optical disk while controlling an axial runout of the flexible optical disk with a stabilizing member that applies an aerodynamic force to the flexible optical disk, and irradiating an optical beam and focusing the optical beam to the flexible optical disk is disclosed that includes the steps of a) generating a first axial runout, b) generating a focus error signal forming an S-curve when the first axial runout is generated, c) determining a position of the optical beam according to the focus error signal, d) generating a second axial runout that is smaller than the first axial runout after step c), and e) conducting at least one of the data recording process and the data reproduction process after step d).

Abstract: An address-accessing device includes first and second information generators for producing first and second information according to the received address signals; a phase offset detector for producing a phase offset according to the first and second information; a reference signal generator for producing a reference signal according to the phase offset, the first information and the second information; and a decoder used to determine the structure type of an address-in-pregroove unit (ADIP) according to the reference value. This address-accessing device is capable of adjusting the decision level and the phase offset automatically to lower the error rate occurring in the address access procedure.

Abstract: A recording apparatus for performing information recording using formation of marks by focusing a first light with an objective lens at a given position in a recording layer included in an optical disc recording medium, includes: a rotation driving unit; a focus servo control unit for condensing a second light on a reflection film and for controlling a position of the objective lens; a recording position setting unit for setting an information recording position of the first light in a focus direction; a tracking servo control unit for controlling a position of the objective lens; an eccentricity amount estimating unit for estimating an eccentricity amount of the optical disc recording medium; and an eccentricity estimation amount acquisition control unit for acquiring an eccentricity estimation amount for each rotation angle within one revolution of the disc.

Abstract: An optical disc playback device is capable of being transitioned to a sleep mode in consideration of an optical disc status or an optical disc drive device status. An optical disc playback apparatus includes a main controller to transmit a sleep mode transition command to an optical disc drive device, and an optical disc drive device controller to check either a status of an optical disc or a status of the optical disc drive device when the sleep mode transition command is transmitted to the optical disc drive device, and to determine whether to perform transition to the sleep mode in response to the optical disc status or the optical disc drive device status.

Abstract: In an optical disc drive apparatus, when a start time of a tracking pull-in operation is adjusted according to the eccentricity amount of the optical disc, a suitable starting point of the tracking pull-in operation can be always captured and the pull-in operation of the tracking control can be stably performed, without depending on the eccentricity amount of the optical disc. Further, the eccentricity amount and an eccentricity phase are detected from a track zero crossing signal before the tracking pull-in, and an eccentricity compensation signal of the track is added to the tracking control signal. As a result, also in the optical disc with the large eccentricity amount, the tracking pull-in operation can be stably performed.

Abstract: An optical disc apparatus including means for calculating a spherical aberration correction quantity of an object lens, reproduced information signal generation means and spherical aberration correction means conducts spherical aberration correction, finds a spherical aberration correction quantity suitable for another layer by calculation on the basis of the obtained spherical aberration correction quantity, and sets the correction quantity as an initial correction quantity of spherical aberration correction. An optical disc apparatus including tilt correction quantity calculation means, reproduced information signal generation means and tilt adjustment means conducts tilt adjustment, finds a tilt correction quantity suitable for another layer by calculation on the basis of the obtained tilt correction quantity, and sets the correction quantity as an initial correction quantity of tilt adjustment.

Abstract: A method and apparatus is described for reducing RRO in storage systems. A disc may be partitioned into a number of equally spaced sectors. An RRO profile may be individually obtained for each sector, a runout control algorithm may be applied to each sector to generate an RROC waveform for the sector to suppress the RRO, and sector RROC waveforms may be assembled into an RROC waveform for a whole revolution and saved in a memory buffer for feed-forward control. The RROC is performed in the time domain, and it may be adapted for each sector to reject the RRO disturbance.

Abstract: An optical disc apparatus includes: a rotation section to rotate an optical disc including a spiral or concentric track with a predetermined track center, with a rotational center of the optical disc as the center; a light source to emit a light beam; an objective lens to collect the light beam on the optical disc; a lens drive section to drive the objective lens in a tracking direction; a light-receiving section to receive a reflected light beam and generate a light-receiving signal; a tracking error signal generation section to generate a first tracking error signal based on the light-receiving signal; an eccentric-state acquisition section to acquire an eccentric state of the track center; a correction section to generate a corrected tracking error signal; and a drive control section to drive the objective lens in the tracking direction by the lens drive section based on the corrected tracking error signal.

Abstract: A disk motor which rotationally drives an optical disk; a rotational phase detector which detects a rotational phase thereof; an optical head having a collecting lens which collects an optical bean; a light detector and an LE signal generator which detect a position of the collecting lens in the optical head as a position signal; an LE signal memory recorder and an LE signal memory which store, in synchronization with a rotational phase to be detected by the rotational phase detector, the positional signal from the LE signal generator; an LE signal memory regenerator which outputs as a correction signal, in synchronization with a rotational phase to be detected, the positional signal which has already been detected; a subtractor; an LE signal filter, a drive circuit and a Tk actuator which move the collecting lens using a signal from the subtractor; and a low pass filter which reduces a high-frequency component of the correction signal are provided.

Abstract: An optical disk drive capable of reproducing data even when warpage is present in an optical disk. A system controller of the optical disk drive reproduces data by setting a maximum speed in accordance with the type of an optical disk, an amount of side-to-side runout, or the like. In the meantime, when a read error arises as a result of trial reproduction being performed at an outer radius of the disk at startup, warpage is determined to be present in the optical disk, and a limitation on the maximum speed is raised. The rotational speed is set to allowable maximum speed of the optical disk drive, and warpage is corrected by means of centrifugal force. When reproduction becomes impracticable for reasons of meandering of a tack, or the like, during the course of reproduction of data, the rotational speed is decreased, to thus perform a retry.

Abstract: A device determines a critical rotation speed of an optical data carrier at which a critical deflection of said optical data carrier may occur. The device includes a drive unit, a measurement unit and a determination unit. The drive unit rotates the optical data carrier according to a sweep covering a predetermined range of rotation speeds. The measurement unit generates a measurement signal indicative of a distance between a surface of the optical data carrier and a reference position corresponding to the sweep. The determination unit determines the critical rotation speed of the optical data carrier by processing the measurement signal on the basis of at least one characteristic of the measurement signal.

Abstract: An optical disc device and tracking control method capable of stable tracking control even for inferior optical discs with tracks decentered by a large amount. The optical disc device and tracking control method includes: obtaining a rotation angle at which the degree of displacement of the track due to the eccentricity of the optical disc becomes maximum on the inner circumference side and the outer circumference side, and detecting the eccentricity amount of the optical disc; and performing track pull-in at the rotation angle, at which the degree of displacement of the track due to the eccentricity of the optical disc becomes maximum, detecting a displacement direction of the optical disc at the time of the pull-in, and moving the slider in the detected displacement direction for a distance equal to or almost equal to the eccentricity amount of the optical disc.

Abstract: A method for distinguishing unbalanced disc in an optical disc reproducing/recording apparatus, comprising following steps: moving an optical pickup head to a first position of an optical disc; rotating the optical disc to a predetermined rotating speed; transferring a focus error signal produced by the optical pickup head to a focus control voltage signal; controlling the optical pickup head by the focus control voltage signal to maintain a focus light spot produced by the optical pickup head on the optical disc; and distinguishing if the optical disc is an unbalanced disc according to the focus control voltage signal.

Abstract: A method for determining runout disc is disclosed. The method comprises: focusing on a focal point on a disc; driving the disc to spin the disc; generating a crossover signal according to a track of the disc crossing the focal point; and determining that the disc is a runout disc when the frequency of the crossover signal exceeds a pre-determine value.

Abstract: A method and system for removing periodic disturbances pertaining to turntable and spindle motor errors during recording of a blank optical information carrier. The periodic disturbances are determined in advance and removed only during recording by a repetitive control/learning feedforward control circuit (88).

Abstract: An information reproducing apparatus (1) is provided with: a detecting device (11) for irradiating an information. recording medium with laser light (LB) and detecting reflected light as a detection signal, the information recording medium including a first recording layer (L0) and a second recording layer (L1); a high pass filter (14) for performing a filtering process on the detected detection signal; and a reproducing device (15, 16) for performing a reproduction process of the filtered detection signal to reproduce the data, the high pass filter attenuates a fluctuation component of the detection signal, caused by a relative eccentricity between the first recording layer and the second recording layer, by a first attenuation amount (34dB) or more.

Abstract: In an optical disk apparatus and a disk rotation speed control method thereof, enabling to rotate a disk at high speed, with stability and certainty, irrespective of mass eccentricity thereof, detection is made on the greatest value and the smallest value on the signal after conducting a process of a band pass filter 511 on a lens error signal in a step response of a pickup, with using a wobble signal in the place of a tracking error signal and chaining an offset, when controlling the rotation speed of the apparatus by loading an optical disk therein, and thereafter, determination is made on whether the disk rotation speed be shifted to the high speed or not, upon basis of a value obtained through comparison of the maximum value (Max_spnup) and the minimum value (Min_spnup) obtained with the greatest value (Max_step) and said smallest value (Min_step) memorized, when shifting the disk rotation to the high speed.

Abstract: A method and apparatus for controlling tilt in an optical disc device are provided. The method includes determining tilt offset values corresponding to different positions of an optical disc for a first tilt control mode, and deciding whether to switch to a static tilt control mode, based on a difference between the detected tilt offset values. If the disc is subject to defect management, a static tilt control mode is selected so that stable focus and tracking servo operations are maintained. If the disc is not subject to defect management, a dynamic tilt control mode is selected so that tilt control optimal for the skew of the optical disc, which gradually increases towards the outer perimeter of the disc, is performed. If the difference between tilt offset values detected respectively for inner and outer peripheral areas of the disc is small when the dynamic tilt control mode is selected, the device determines that the skew is low and changes the tilt control mode to the static tilt control mode.

Abstract: This optical disk device includes a pickup head, a spindle motor, a signal generation unit, a runout amount calculation unit, and an out of balance disk detection unit. The signal generation unit generates a tracking error signal. The runout amount calculation unit controls the rotational speed of the spindle motor to first and second disk rotational speeds, and obtains, at these rotational speeds, runout amounts TE1 and TE2 of a tracking error signal, and runout amounts FE1 and FE2 of a focus error signal. And an out of balance disk detection unit detects that this optical disk is an out of balance disk, if the absolute value of (TE2×FE2)/(TE1×FE1) is greater than or equal to a threshold value.

Abstract: In a conventional method for preventing a collision between a lens and an optical disc which uses a control system similar to the servo control of the optical disc, it is feared that, when there is no need to apply the servo, the collision prevention method may not perform its function satisfactorily. In an optical disc device that operates with a part of its functions suspended for reduced power consumption, the conventional method is not enough to avoid the collision between the lens and the optical disc. By arranging the lens/disc collision prevention mechanism independently operable, it is possible to prevent the collision between the lens and the disc even during the operation with limited functions.

Abstract: A warpage angle measurement apparatus and a warpage angle measurement method are provided that can measure an angle of warpage of an optical disc and a cartridge for the optical disc caused by a rapid environmental change such as a temperature change or a humidity change in a short time. The warpage angle measurement apparatus 10 includes: a constant temperature chamber 22 for accommodating an optical recording medium 20 formed by mounting the optical disc 16 as an object to be measured in the cartridge 18 and for adjusting a surrounding of the optical recording medium 20 to have a predetermined environmental condition; a laser oscillator 24 for causing laser oscillation to emit laser light to the optical disc 16; and a light-receiving unit 26 for receiving the laser light reflected from the optical disc 16 and detecting a relative angle of an optical path L2 of the reflected laser light with respect to an optical path L1 of the emitted laser light.

Abstract: A method for track jumping for optical recording media exhibiting eccentricity, and to an apparatus for reading from and/or writing to optical recording media using such method is disclosed. The method for track jumping for optical recording media exhibiting eccentricity, whereby a sled and/or an actuator are moved from a start track to an end track, includes the steps of: determining the eccentricity of the optical recording medium, initiating the track jump at minimum eccentric acceleration, and completing the track jump at minimum eccentric acceleration.

Abstract: An offset amount measuring method is provided with: a recording process for measurement (i) of recording information for measurement, into a recording track in the L0 layer, by a predetermined section, from a measurement reference position, and of (ii) recording the information for measurement, into a recording track in the L1 layer, by the predetermined section, from or toward a measurement correspondence position, which is associated with the measurement reference position by the pre-format address; a first detecting process of detecting a border of a first recorded area in which the information for measurement is recorded and a first unrecorded area in the first recording track, on the basis of a difference in reflectance between the first recorded area and the first unrecorded area; a second detecting process of detecting a second border position in the recording track in the L1 layer, on the basis of a difference in reflectance; and a determining process of determining the offset amount, on the basis of

Abstract: An apparatus comprising a photo diode array, a differential push-pull generator circuit and an attenuation prediction circuit. The photo diode array may be configured to generate a plurality of beam signals. The differential push-pull generator circuit may be configured to generate a differential push-pull signal with one or more gain blocks in response to (i) a plurality of input signals, (ii) a gain approximation signal and (iii) the plurality of beam signals. The attenuation prediction circuit may be configured to (i) predict an attenuation factor of the differential push-pull signal and (ii) generate the gain approximation signal in response to (a) a plurality of amplification signals and (b) a plurality of angle signals.

Abstract: A method and apparatus position a beam spot on a recording medium. The positioning includes (a) observing a first center error in a first closed loop control during tracking mode, the first center error including a repeatable run out (RRO) error, (b) estimating a center error (CE)-RRO from the first center error, the CE-RRO being part of the first center error caused by the RRO, (c) observing a second center error in a second closed loop control during a rough seek, (d) subtracting the CE-RRO from the second center error, (e) controlling the beam spot based on the second center error less the CE-RRO during the rough seek, and (f) adding an open loop control to the second closed loop control during the rough seek, the added open loop control inducing a motion of the lens relative to an optical center of the OPU during the rough seek.

Abstract: A method controls an assembly using an oscillating wave, such that the assembly moves in an oscillated manner in relation to a surface of an optically writable medium in correspondence with oscillation of the oscillating wave. The assembly generates a beam towards the surface of the optically writable medium. A proximity signal is detected in response to the beam being generated towards the surface of the optical medium, and denotes closeness of the assembly to the surface. A number of peaks within the proximity signal are determined. The time at which each peak within the proximity signal occurs is correlated with a value of the oscillating wave at that time, yielding a number of time-value pairs. The topology of the surface of the optical medium is approximated from these time-value pairs.

Abstract: A radial runout detection method and device for an optical disk drive, which sets a reference locus at a location distant from a current beam locus by M, a minimum track number, a maximum track number and a detection time, and executes the following steps in the detection time: increasing M when a data track across the current beam locus moves toward a direction of the reference locus, and otherwise decreasing M; setting the minimum track number as M when M decreased is smaller than the minimum track number; setting the maximum track number as M when M increased is greater than the maximum track number. Accordingly, a runout track number is computed by subtracting the minimum track number from the maximum track number.

Abstract: An apparatus which stabilizes an operation of a disc driver in a mode conversion setting section includes a pickup which reads information from a disc that is inserted into the disc driver, a filter which performs a low-pass filtering of a servo error signal that is generated during an operation of the pickup, a selector which selects one of the servo error signal and the low-pass filtered servo error signal from the filter and outputs the selected servo error signal to drive the pickup using the selected servo error signal, and a control signal generator which generates a signal to control the selector to select the low-pass filtered servo error signal in a mode conversion setting section of the disc driver. Accordingly, a defocus and a detrack can be prevented in the mode conversion setting section of the disc driver.

Abstract: An optical disk apparatus detects a predetermined tilt angle and a predetermined focus bias at least two detection points on an inner and an outer circumferences of the optical disk. On the basis of the predetermined tilt angle detected at the detection points, the apparatus estimates the predetermined tilt angle at a radial position of the optical disk, and also estimates a focus bias. The apparatus controls the tilt angle according to a radial position of target track and a focus bias on the basis of estimation results at the time of recording and reading data on the optical disk.

Abstract: An optical disc device and tracking control method capable of stable tracking control even for inferior optical discs with tracks decentered by a large amount. The optical disc device and tracking control method includes: obtaining a rotation angle at which the degree of displacement of the track due to the eccentricity of the optical disc becomes maximum on the inner circumference side and the outer circumference side, and detecting the eccentricity amount of the optical disc; and performing track pull-in at the rotation angle, at which the degree of displacement of the track due to the eccentricity of the optical disc becomes maximum, detecting a displacement direction of the optical disc at the time of the pull-in, and moving the slider in the detected displacement direction for a distance equal to or almost equal to the eccentricity amount of the optical disc.

Abstract: There is provided a disk recording apparatus capable of minimizing a servo error and recording in the last zone at the maximum one of the recording speeds specified in the apparatus or disk recording medium even if the disk recording medium is in poor condition. At any position during disk activation, an axial-run-out and eccentricity measuring circuit (115) measures the eccentricity of the disk recording medium. A CPU (101) calculates the upper-limit rotation speed from the measurement, divides the recording area into zones in such a manner that the disk recording medium rotates at speeds lower or equal to the upper-limit rotation speed, determines the maximum one of the recording speeds specified in the apparatus and supported by the disk recording medium for each zone, sets a zone CLV table, and stores the table in a RAM (102). Then, the recording speeds are changed at zone boundaries according to the zone CLV table set based on the upper-limit rotation speeds calculated from the eccentricities.

Abstract: An information carrier apparatus for accessing an information carrier having at least one track formed therein includes a times crossed detection section for detecting the number of times that a head structured to access the information carrier has crossed the track; an eccentricity direction detection section for detecting an eccentricity direction of the information carrier based on the number of times; an eccentricity distance detection section for detecting an eccentricity distance of the information carrier based on the eccentricity direction and the number of times; and an eccentricity correction section for correcting eccentricity of the information carrier based on the eccentricity direction and the eccentricity distance.

Abstract: An open-loop test procedure under high rotating speed is entered to compute a first TE crossing track number. The first TE crossing track number greater than a first threshold indicates an unbalanced disc and results in a low-speed reading procedure. On the other hand, the first TE crossing track number less than a second threshold value that is less than the first threshold value indicates a normal disc and results in a high-speed reading procedure. When the first TE crossing track number lies between the first and second threshold values, another open-loop test procedure under low rotating speed is entered to compute a second TE crossing track number. A low-speed reading procedure is performed when the second TE crossing track number is greater than a third threshold value, and a high-speed reading procedure is performed when the second TE crossing track number is less than the third threshold value.

Abstract: An optical disk drive capable of detecting a surface deviation of a disk during a very short period includes an analog-to-digital converter (ADC) converting a focus error signal output from a pickup into digital data, and a central processing unit (CPU) writing an output of the ADC to a memory during one rotation of a motor according to a timing of a pulse signal output from a spindle motor. After that, the CPU reads data written to the memory and obtains a sine curve that minimizes the sum of squares of errors among data by a least square method. The CPU obtains a peak-to-peak value of the obtained sine curve and compares the peak-to-peak value to a predetermined threshold value, thereby determining the existence of the surface deviation of the disk.

Abstract: An information recording apparatus according to one aspect of this invention comprises a detection unit configured to detect a manufacturing error unique to an information storage medium, a transmission unit configured to transmit the manufacturing error detected by the detection unit to an external apparatus, a reception unit configured to receive a recordable capacity which is calculated by the external apparatus on the basis of the manufacturing error transmitted from the transmission unit, a limitation unit configured to limit data to be supplied on the basis of the recordable capacity received by the reception unit, and a recording/aborting unit configured to record the recording data, supply of which is limited by the limitation unit, or to abort recording of the recording data.

Abstract: The present invention can promptly start the tracking control. According to an embodiment of the present invention, after making it possible to discriminate the groove G and land L by the initial drive for the objective lens, the servo control and brake control are executed under an optimum condition when the objective lens is initially driven to the inner circumference direction to be outer eccentricity where a spot Pt is easily pulled in so as to pull in the spot Pt and start tracking control, and, in case the TR control error is raised when pulling in the spot Pt in an eccentricity speed minimum region AR1 for the first time, assuming that the eccentricity speed minimum region AR1 is inner eccentricity, the spot Pt is pulled in at the next eccentricity speed minimum region AR2 in which the eccentricity direction becomes opposite and the tracking control is started.

Abstract: An optical storage system includes a pickup head for picking up data from a storage medium. Firstly, the maxima of a tracking error signal and runout are obtained in a calibration procedure in a close loop formed by an optical pickup head, a pre-amplifier, a compensator, a band-pass filter and a maximum detector. A calibration factor is then defined and derived by using the obtained maxima and nominal factors of a power amplifier and the optical pickup head of the optical storage system. The path formed by the series-connected band-pass filter and maximum detector is then disabled, while the calculated calibration factor is then stored in the compensator. The optical storage system may operate in a close loop formed by the optical pick head, pre-amplifier, compensator, a power amplifier under a normal operation procedure so that the optical storage system may record or read data onto/from an optical disc under the compensation provided by the calibration factor.