Abstract: Reproduction of digital data using a fallback mechanism is disclosed. The digital data can be reproduced in a first mode and in an at least second mode, the operability of a selected mode is monitored and in a situation of failure, a switching between the mode in which a failure is detected to a mode which is operable can be made, so that least some functionality is ensured. An apparatus is disclosed, the apparatus being operable in a first mode where the digital data is accessed in a first format, and the apparatus being operable in an at least second mode where the digital data is accessed in at least a second format. Also a system, a method, a computer readable code and a data stream are disclosed.

Abstract: Some of the embodiments of the present disclosure provide a method for operating a disc drive system, the method comprising based at least in part on a first injector signal, oscillating a focusing apparatus of the disc drive system; while oscillating the focusing apparatus of the disc drive system and rotating a disc placed within the disc drive system, estimating an amplitude of a track crossing speed signal; generating a second injector signal having a frequency that is substantially the same as a frequency of the first injector signal; and based at least in part on the estimated amplitude of the track crossing speed signal and the second injector signal, estimating a sign of the track crossing speed signal.

Abstract: Aspects of the disclosure provide a sync mark detector. The sync mark detector includes a first unit configured to decay over time a value indicating a length of a bit format, a second unit configured to compare the decayed value with a detected length of the bit format to determine a new length, and a third unit configured to detect a sync mark based on the detected length and the new length.

Abstract: Systems and methods are disclosed for testing dies in a stack of dies and inserting a repair circuit which, when enabled, compensates for a delay defect in the die stack. Intra-die and inter-die slack values are determined to establish which die or dies in the die stack would benefit from the insertion of a repair circuit.

Abstract: Provided is an optical pickup device that suppresses a fluctuation of a tracking error signal caused by stray light when recording/reproducing information on/from an optical disc including a plurality of recording layers and attains size reduction. It includes a laser diode emitting laser light of about 405 nm in wavelength, an objective lens irradiating the optical disc with an optical beam emitted from the laser diode and having a numerical aperture of about 0.85, and a detector including a detection part receiving the optical beam reflected from the optical disc. An optical magnification from the optical disc to the detector is set within a range from about 10× to 15×.

Abstract: An optical disc device includes: a diffraction element receiving as input reflected light from an optical disc recording medium, including a first diffraction area formed in a position where light in the center portion of incident light flux is diffracted, a second diffraction area formed so as to be in contact with an outer edge of the first diffraction area, and a third diffraction area formed so as to be in contact with an outer edge of the second diffraction area; and a light receiving/signal generating unit which generates a focus error signal and a lens error signal based on light diffracted at the third diffraction area; with the light receiving/signal generating unit receiving light diffracted at the second diffraction area, and generating the focus error signal based on the received light signal thereof and a received light signal obtained by receiving light diffracted at the third diffraction area.

Abstract: A method for determining an optimal combination of focus bias and spherical aberration compensating value (SA value) in an optical disc drive is provided. Firstly, a first focus bias is set, the SA values are adjusted and the corresponding tracking error signal values are measured. Second-order-approximation is performed to obtain a first maximum value of tracking error signal. Secondly, a second focus bias is set, the SA values are adjusted and the corresponding tracking error signal values are measured. Second-order-approximation is performed to obtain a second maximum value of tracking error signal. Thirdly, a third focus bias is set, the SA values are adjusted and the corresponding tracking error signal values are measured. Second-order-approximation is performed to obtain a third maximum value of the tracking error signal. The three maximum values are compared to obtain the optimal combination of focus bias and SA compensating value in the optical disc drive.

Abstract: A reproducing method includes: irradiating a laser spot for servo to which astigmatism making up a generally 45-degree angle in the tangential direction of an information recording track has been applied, and one or more laser spots for reproduction, onto a recording medium where a track group is formed with multiple information recording tracks adjacent with a narrower track pitch than a track pitch equivalent to optical cut-off, and also where a track group pitch is wider than the track pitch equivalent to optical cut-off; and subjecting one or more laser spots for reproduction to on-track control as to one of the information recording tracks by taking a tangential push pull signal obtained from reflected light information of the laser spot for servo as a tracking error signal, and performing tracking servo control using this tracking error signal, and reproducing data from the reflected light information thereof.

Abstract: An optical disc according to the present invention has a first defect management area to which first defect management information corresponding to non-permanent defects is added, and a second defect management area to which second defect management information corresponding to permanent defects is added. The second defect management information added to the second defect management area is non-rewritable.

Abstract: A disc device for recording and/or reproducing information with respect to a disc having flexibility includes a head for writing and/or reading, the head being disposed below the disc; a disc rotating section which rotates the disc; and a head retracting section which retracts the head to a retracted position where contact with the disc is avoidable, based on a judgment that power supply to the disc device is cut off.

Abstract: An optical defect detection method for patterned media includes: irradiating a laser beam onto a patterned medium and obtaining reflected light by reflection very close to a sample; outputting the reflected light as an analog electrical signal from an optical receiver; converting the analog signal to a digital signal; obtaining a surface profile in a track direction by sampling the analog signal; obtaining a servo area profile by setting a slice for detecting servo area; calculating an average value in a track width direction based on plural servo area profiles; generating a master servo area profile based on the average value; obtaining a difference between the master servo area profile and the specific servo area profile; and detecting the presence of a defect including surface roughness, process fluctuation, and adhesion of foreign matters, from a differential waveform.

Abstract: It is to provide an optical disc recording apparatus and a recording power control method that are adapted to high-speed recording and can set an optimal erasing power with high accuracy. A test writing signal detector reproduces a test writing signal of a predetermined mark length or space length with varied power, and detects the number of error mark signals and an amplitude value of an envelope. A controller obtains a first threshold Pe0 of the erasing power based on the number of error mark signals in a region where laser power is low, and obtains a second threshold Pe1 of the erasing power based on the amplitude value in a region where the laser power is high. Then, the controller sets an optimal value of the erasing power from an average value of the first and second thresholds.

Abstract: To improve the track pull-in performance in the servo control of an optical disk device, track pull-in is performed by driving the objective lens by an actuator, outputting an electrical signal according to the amount of reflected light from the optical disk, generating a focus error signal and a tracking error signal from the output electrical signal, outputting a focus control signal based on the focus error signal to drive the actuator in the rotation axis direction, outputting a tacking control signal based on the tracking error signal to drive the actuator in the radial direction of the optical disk, controlling the speed of the actuator so that the cycle of the tracking error signal is kept substantially constant, moving the objective lens in the radial direction before the start of the speed control, and supplying the tracking control signal to the actuator after the start of the speed control.

Abstract: According to one embodiment, an information processing apparatus includes an optical disc drive, a measuring module in the optical disc drive, and a measurement value reception module. The measuring module is configured to measure a value related to an operation of a predetermined motor in the optical disc drive, which is executed during a time period of power-up of the optical disc drive. The measurement value reception module is configured to receive a measurement value related to the operation of the predetermined motor from the optical disc drive in response to an event of being requested to turn off the power of the optical disc drive, and to store the received measurement value in a storage device.

Abstract: An information reproducing apparatus (1) is provided with: a waveform shaping device (14) for performing waveform shaping on a read signal (RRF) read from a recording medium (100), on the basis of a reference amplification factor; a correcting device (18) for correcting waveform distortion occurring in a read signal corresponding to at least a long mark, of the read signal on which the waveform shaping is performed; and a waveform equalizing device (15) for performing a waveform equalization process on the read signal in which the waveform distortion is corrected, the waveform shaping device arbitrarily increases the reference amplification factor.

Abstract: An information reproducing apparatus (1) is provided with: a correcting device (18) for correcting waveform distortion occurring in a read signal corresponding to a long mark, of a read signal (RRF) read from a recording medium (100); and a processing device (15) for performing a PRML (Partial Response Maximum Likelihood) process on the read signal in which the waveform distortion is corrected.

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: The optical disc comprises a substrate layer, a read-only data layer having a pit/land data structure including user data and control data arranged in tracks on the substrate layer, and a nonlinear layer with a super-resolution structure disposed on the data layer, wherein the control data are correctly readable only by including a reverse rotation of the disc. The control data include in particular a protection code for the disc, for example a copy protection code, so that the user data of the disc are only readable after reading of the control data.

Abstract: An information reproducing apparatus (1) is provided with: an offset adding device (19-1, 19-2) for adding a first offset value (OFS) which can be set to be variable, to a read signal (RRF) read from a recording medium (100); a correcting device (18) for correcting waveform distortion occurring in a read signal corresponding to a long mark, of the read signal to which the first offset value is added; an offset subtracting device (19-2, 19-3) for subtracting a second offset value (OFS) which can be set to be variable, from the read signal in which the waveform distortion is corrected; and a waveform equalizing device (15) for performing a waveform equalization process on the read signal in which the second offset value is subtracted.

Abstract: An information recording medium 1 at least comprises a substrate 13 having a microscopic pattern 20, which is constituted by a shape of continuous substance of approximately parallel grooves formed with a groove section G and a land section L alternately, a recording layer 12 formed on the microscopic pattern 20 and a light transmission layer 11 formed on the recording layer. The microscopic pattern 20 is formed so as to satisfy a relation of P<?<NA and a thickness of the light transmission layer 11 is within a range of 0.07 to 0.12 mm, wherein P is a pitch of the groove section G or the land section L, ? is a wavelength of reproducing light beam and NA is a numerical aperture of an objective lens. Further, there provided an information recording medium, which is improved in cross erase and recorded in high density, and a reproducing apparatus and a recording apparatus for the information recording medium.

Abstract: An information recording medium 1 at least comprises a substrate 13 having a microscopic pattern 20, which is constituted by a shape of continuous substance of approximately parallel grooves formed with a groove section G and a land section L alternately, a recording layer 12 formed on the microscopic pattern 20 and a light transmission layer 11 formed on the recording layer. The microscopic pattern 20 is formed so as to satisfy a relation of P<?<NA and a thickness of the light transmission layer 11 is within a range of 0.07 to 0.12 mm, wherein P is a pitch of the groove section G or the land section L, ? is a wavelength of reproducing light beam and NA is a numerical aperture of an objective lens. Further, there provided an information recording medium, which is improved in cross erase and recorded in high density, and a reproducing apparatus and a recording apparatus for the information recording medium.

Abstract: A backup method includes reading record information of an optical disc; when the reading operation fails, utilizing an optical disc drive to read backed up record information at a plurality of specified positions in the lead-out area; checking a status of a session as a preparation for following recording; utilizing the optical disc drive to record data into a session on the optical disc; updating record information of the optical disc to generate an updated record information when recording of the session is completed and simultaneously recording the updated record information including a TOC block within the lead-in area of the optical disc to a plurality of specified positions on the optical disc according to different data types of the record information to serve as backed up record information; and ending a recording operation of the session.

Abstract: A recording method of an optical recording medium comprises irradiating the medium with a laser having m pulse sets each comprising a heating pulse and a cooling pulse, in which m is a natural number; and scanning the medium with the laser at a scanning speed v to record marks each of a length nT, in which n is a natural number of 3 or more and T is a clock cycle, wherein a length TCPn of a final cooling pulse is determined in accordance with the scanning speed v using the following functions, in v<v0, TCPn/T=f1,n(v) in v v0, TCPn/T=f2,n(v), where the f1,n(v) and f2,n(v) each represents a continuous function of the scanning speed v and satisfies the condition where an existence ratio of abnormal marks is 1.0×10?4 or less, and v0 is a selectable scanning speed.

Abstract: The present invention relates to a method for operating an optical drive system capable of reproducing/recording information from/to an optical carrier (30), wherein a position error and a speed error of a radiation spot (12, 53) on the carrier has been created due to an unreliable error signal which has been generated due to a surface defect (52). The method includes the steps of registering values of e.g. servo signals, determining the occurrence of a defect using a defect detector DEFO (22), generating a first and a second compensation signal and applying these compensation signals to the control system (10) of the optical drive system. The first compensation signal is capable of reducing the speed error and the second compensation signal is capable of reducing the position error. Thus, the application of the compensation signals immediately after the unreliable error signals reduces the position error and the speed error of the focussed radiation spot (12, 53).

Abstract: A method and apparatus for controlling a light source for use with an optical disc having optimum power values for different stages in a writing signal for the optical disc, includes comparing current operational characteristics of the light source to previous operational characteristics, and, when the current operational characteristics differ from the previous operational characteristics and a stage in the writing signal has overlapping power, determining a compensation voltage based on the current operational characteristics and an optimum power value for that stage.

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: An optical disc device includes: a spindle motor for rotating a disc; a motor driving circuit for applying a voltage to the spindle motor to drive the spindle motor; an optical pickup for irradiating the disc with an optical beam; and a detector for, after the motor driving circuit starts voltage application to the spindle motor, measuring a pit length based on reflection light, on the disc, of the optical beam irradiated by the optical pickup and then detecting based on a result of the measurement that the spindle motor is in short condition. In the optical disc device, upon detection by the detector that the spindle motor is in short condition, the motor driving circuit stops the voltage application to the spindle motor.

Abstract: If a failure is detected during operation of information recording in an optical disc apparatus, the optical disc apparatus stops the recording operation, changes the number of rotations of the optical disc to a low-speed value, seeks a selected recording region, performs OPC processing and trial write operation, measures a ? value as a result of the trial write operation, calculates optimal recording power based on the difference between the measured ? value and a target ? value and recording power set in the OPC processing, and starts the operation of information recording with the selected number of rotations for low-speed operation by use of the optimal recording power.

Abstract: A disk device includes: an optical pick-up, operable to reproduce data recorded in a disk; a flaw detector, operable to output a flaw detecting signal when a flaw formed on the disk is detected; and a jump controller, operable to control a track jump of the optical pick-up including a first track jump and a second track jump subsequent to the first track jump. A timing of starting to control the track jump corresponding to a still reproduction mode is determined based on a rotational position of the disk. When the flaw detecting signal is outputted in a time period in which the jump controller controls the first track jump corresponding to the still reproduction mode, the jump controller sets a timing for stating the second track jump to a timing different from a timing for starting the first track jump.

Abstract: When receiving the reproduced data from the optical disc and buffering same, the buffering from the correct position can be started on the basis of the synchronous signal and the address information included in the sub data which was received simultaneously. There is provided a method for controlling the buffering of the main data which is reproduced from the optical disc, in which the main data and the sub data are received with taking word clocks which are partitioning timings having plural bits of the main data as a unit as references, a synchronous signal which is in synchronization with the main data is generated, and the buffering of the main data is started on the basis of the synchronous signal.

Abstract: A method and an apparatus for recording and/or reproducing data in which a recording and/or reproduction velocity is be reduced when a data recording and/or reproduction error occurs due to a defect of an optical disc during recording of data on and/or reproduction of data from the optical disc. The method includes: recording data on an optical disc that is rotating at a predetermined constant angular velocity; determining whether a data recording error occurs; and if it is determined that a data recording error has occurred, recording data on the optical disc that is rotating at a constant angular velocity which is lower than the predetermined constant angular velocity.

Abstract: Disclosed is an optical disc apparatus that sets a plurality of virtual zones, which correspond to a plurality of zones that are arranged in the radial direction of an optical disc, for a plurality of recording layers of the optical disc. When a servo signal distortion is detected in a virtual zone to change the rotation speed of the optical disc to a low speed in the virtual zone during an information recording or reproduction operation relative to a first recording layer, the optical disc apparatus stores the change information. When a recording or reproducing operation is to be performed in a virtual zone of a second recording layer, which is in the same disc radial position as the virtual zone of the first layer, the optical disc apparatus changes the rotation speed of the optical disc for the virtual zone to a low speed in accordance with the change information.

Abstract: An apparatus for changing a recording speed of an optical recording medium by analyzing wobble signals in real time during a recording operation, includes a signal process unit which outputs a cyclic redundancy check (CRC) signal that checks for a generation of errors on the optical recording medium from absolute time in pregroove (ATIP) information output from the optical recording medium during the recording operation, and a speed control unit which changes the recording speed during the recording operation according to a comparison of the CRC signal output from the signal process unit with a reference value. In the apparatus, the recording speed is limited or lowered in response to a signal quality of a recording section being less than an acceptable level during the recording operation. Accordingly, buffer under run and defects of read-in start position and seek fail, which are generated during a ZCLV operation, are prevented.

Abstract: A method is provided for controlling a play speed in an optical disc device in which the current play speed is rapidly lowered when the address information of an optical disc such as a CD or DVD is abnormally detected under the condition in which the transfer rate of data temporarily stored in a buffer is a basic speed 1×, and in a sequential play mode for sequentially reading and reproducing A/V data recorded on the optical disc, thereby being capable of efficiently preventing discontinuous reproduction of A/V data caused by the repetition of pause and play operations during the sequential play operation.

Abstract: A write retry processing unit repeats a write retry operation of a write and a verify, while performing a setting change of a focus offset for recording a data on an optical storage medium in case a verify error occurs in executing the write and a verify try fails. A learning processing unit retains a sum total of the number of adding times of the successful focus offset and the number of subtracting times of the successful retry offset as a learning result at the successful time of the write retry, and a write condition changing unit changes the focus offset setting value of the default so as to be drawn near to the latest focus offset which succeeds in the retry when the absolute value of the learning result retained in the learning processing unit is equal to or more than a threshold value.

Abstract: A recording method for an optical disk drive is implemented as follows. First, at least one of the level of the focusing error signal, the level of the tracking error signal, a wobble synchronization pattern loss, the error rate of demodulating a wobble signal and the frequency of buffer under-run occurrence is detected. If at least one detected value exceeds the preset value, the recording will be ceased. Then, the rotation speed of the optical disk drive is decreased, and the recording is resumed with the decreased rotation speed.

Abstract: There is provided an apparatus capable of switching between a laser that emits light having a wavelength suitable for detecting samples and a laser required for reading traced data, while an analysis optical disc is being traced. In an analyzer in which an analysis disc having a sample to be analyzed which is located in a part of its track is irradiated with laser light to read the state of the sample, a selector switch alternately selects a laser having a wavelength for reading data represented by bits or wobble grooves on the disc and a laser having a wavelength suitable for detecting a sample, in response to an instruction from a control unit.

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: In an optical disc device comprising: a pickup 3 having a laser diode and generating a laser beam for recording onto an optical disc 1; a disc motor 2 that drives the rotation of an optical disc mounted thereon; a stepping motor that moves the pickup in the radial direction of the disc; and a system controller 6 that supplies drive current to the laser diode, and that controls the rotational speed of the disc motor and the position of the pickup by means of the stepping motor; the pickup has a temperature sensor 31 in its interior and system controller 6 restricts the drive current supplied to the laser diode in accordance with a detected temperature during data recording and controls the rotational speed of the disc motor, based on the detected temperature and the data recording properties of the optical disc which have been determined.

Abstract: Reproduction of digital data using a fallback mechanism is disclosed. The digital data can be reproduced in a first mode and in an at least second mode, the operability of a selected mode is monitored and in a situation of failure, a switching between the mode in which a failure is detected to a mode which is operable can be made, so that least some functionality is ensured. An apparatus is disclosed, the apparatus being operable in a first mode where the digital data is accessed in a first format, and the apparatus being operable in an at least second mode where the digital data is accessed in at least a second format. Also a system, a method, a computer readable code and a data stream are disclosed.

Abstract: An apparatus is provided for disc rotation control in an optical storage system, which is capable of generating a focusing error signal from light that was reflected by a loaded optical disc. The apparatus includes a focus controller for processing the focusing error signal to obtain a focus output signal, a low pass filter unit for processing the focus output signal by low pass filtering to obtain a filtered signal, a direct current level remover for removing a direct current component of the filtered signal to obtain a warp-indicating signal, and a speed controller for comparing the warp-indicating signal with a predetermined threshold value to determine extent of warping of the optical disc. The speed controller is operable to control the optical storage system so as to limit maximum rotation speed of the optical disc according to result of the comparison made by the speed controller.

Abstract: A photoreceiver includes: a first light-receiving section divided into two regions by a border extending in a radial direction, and is disposed in a portion where it can receive a +1st order diffraction ray of the main beam from the polarization hologram, so as to detect a spherical aberration; a second light-receiving section is divided into two regions by a border extending in the radial direction, and is disposed in a portion where it can receive a +1st order diffraction ray of the first sub-beam from the polarization hologram, so as to detect a spherical aberration; and a third light-receiving section is divided into two regions by a border extending in the radial direction, and is disposed in a portion where it can receive a +1st order diffraction ray of the second sub-beam from the polarization hologram, so as to detect a spherical aberration.

Abstract: A novel optical disc driving system and method for determining the rotation speed of an optical disc are provided, which allow to determine the highest rotation speed optimal for reading out audio and video data in the optical disc in accordance with the environmental conditions in the vicinity of the optical disc driving unit, in particular the time and temperature. The rotation speed is determined by reading out the data recorded in the optical disc under the permissible operation conditions, which result from both actually measured parameters for environmental conditions and predetermined upper and lower limits of the rotation speed for a disc spindle motor for the respective ranges of parameters. The parameters for environmental conditions and the upper and lower limits of the rotation speed can be manually changed by user's instruction.

Abstract: A motor control system comprises a motor controller and a clamp apparatus and is used for controlling a motor apparatus. The motor controller is used for generating a motor control output according to a reference signal and a feedback signal from the motor apparatus. The clamp apparatus is used for receiving the motor control output and has a clamp function for clamping the motor control output. The clamp apparatus determines whether the clamp function should be activated to clamp the motor control output within an acceptable clamp range according to at least one motor stability signal. When the motor stability signal indicates that the motor apparatus has been in a stable state, the clamp apparatus clamps the motor control output from the motor controller in the acceptable clamp range, so as to avoid an abnormal motor control output resulting from external sudden change.

Abstract: A noise removal circuit of the present invention comprises a 180-degree odd multiple shifting section for outputting a 180-degree shifted signal that is phase-shifted from an input signal by an odd multiple of 180 degrees and difference output section for outputting a difference between the input signal and the 180-degree shifted signal. The noise removal circuit comprises a 360-degree shifting section for outputting a 360-degree shifted signal that is phase-shifted from an input signal by an integral multiple of 360 degrees and sum output section for outputting a sum of the input signal and the 360-degree shifted signal.

Abstract: An optical disc drive includes a spindle motor and a computer program. The spindle motor is adapted for rotating an optical disc. The computer program configures the optical disc drive to perform consecutive steps of a method for detecting eccentricity of the optical disc, including: a) while the optical disc drive operates under focused and track-locked conditions, controlling the spindle motor to rotate the optical disc at a specified rotation speed; b) measuring an eccentricity value of the optical disc being rotated by the spindle motor; and c) comparing the eccentricity value measured in step b) with a reference value to determine extent of eccentricity of the optical disc.

Abstract: This invention describes a method and apparatus to determine a safe rotational speed for a CD/DVD drive by detecting the amount of vibration of the disk by measuring the operating conditions of the spindle motor. A disk drive includes a motor for rotating the disk and an apparatus for monitoring the current or back emf in the windings of the motor. When the current or the back emf varies from a normal level, the disk is vibrating and a signal indicating a vibration condition is sent to the spindle motor driver. The maximum speed that the disk rotated is slowed until a vibrating condition is no longer detected and the rotational speed associated with a particular disk is based dynamically on the amount of vibration detected. Disks may also be identified that cannot spin a minimum rate of speed.

Abstract: An optical media drive contains light reflective surfaces positioned about a transparent center portion of the optical media. The light reflective surfaces reflect laser light from a laser unit of the drive which is directed toward the transparent center portions of the optical media. Defects such as cracks in the optical media disturb the reflection. The disturbance is detected by a laser lens and represented by a signal corresponding to the size of the defect. Information about the cracks is used to determine a safe spin rate for the optical media.

Abstract: An exposure apparatus for an optical disc used for eliminating the vibrations in the propagating direction when a rotation mechanism rotates. The slider controller 40 and the spindle controller 41 of the exposure apparatus 1 are activated, and the then the optical disc begins to be rotated by an AC synchronized motor. Through a condensing device 9, laser beams emitted form the laser source 6 are irradiated on the optical disc for exposure. At this time, the optical disc is eccentrically chucked on the rotation mechanism, resulting a rotational vibration of the whole rotation mechanism. A measurer 17 is used for detecting a propagating component of the rotational vibration, and a vibrator controller 42 controls the vibrator 20 as the output of the measurer 17 approaches zero. Therefore, the vibration in the propagating direction of the base 2 is cancelled, and the propagation accuracy is increased and the exposure quality is enhanced.

Abstract: The invention provides a reliable write method of data on an optical record carrier without changing the conventional configuration of an information recording apparatus. The invention uses the errors occurred in reading ATIP codes and/or the reflected signal from the surface of the record carrier to decide if the storage unit on the record carrier is eligible to store data. The defective storage units are labeled as unrecordable.