Abstract: A first clock signal is generated from a reference clock signal. A first frequency associated with the first clock signal is less than a reference clock frequency associated with the reference clock signal. The first clock signal is propagated towards a first component of an integrated circuit through a clock tree. A second clock signal having a second frequency is generated from the first clock signal at a terminal point of the clock tree. The second clock signal is provided to the first component.

Abstract: A process is described for manufacturing an improved PMOS semiconductor transistor. Recesses are etched into a layer of epitaxial silicon. Source and drain films are deposited in the recesses. The source and drain films are made of an alloy of silicon and germanium. The alloy is epitaxially deposited on the layer of silicon. The alloy thus has a lattice having the same structure as the structure of the lattice of the layer of silicon. However, due to the inclusion of the germanium, the lattice of the alloy has a larger spacing than the spacing of the lattice of the layer of silicon. The larger spacing creates a stress in a channel of the transistor between the source and drain films. The stress increases IDSAT and IDLIN of the transistor. An NMOS transistor can be manufactured in a similar manner by including carbon instead of germanium, thereby creating a tensile stress.

Abstract: An optical disc has a read-only system lead-in area and a recordable data area. Disc boundary information representing a boundary in a radial direction of an area on which capability of recording at a predetermined recording speed is guaranteed is recorded on the system lead-in area while being related to each tuple speed. An optical disc device, upon user's instruction of tuple-speed recording, compares the boundary information related to the instructed tuple speed with a present recording position, performs recording at the instructed tuple speed if the present recording position is on the outside of the boundary, and performs recording at a tuple speed lower than the instructed tuple speed if the present recording position is on the inside of the boundary.

Abstract: A recording apparatus includes first identification means for identifying, in accordance with information read from a disk medium and related to a format of data recorded on the disk medium, the format defined from a purpose of the recorded data and a version of the format; storage means for storing data in which the version and information on whether processing that can be executed is executable are associated; determination means for determining, in accordance with the version and by referring to the data stored in the storage means, whether processing that can be executed is limited; generation means for generating first image data for displaying a first image representing that the processing that can be executed is limited when the determination means determines that the processing that can be executed is limited; and display control means for controlling display of the first image in accordance with the first image data.

Abstract: A servo controller in a system includes a kick/brake control unit and a compensation unit. The kick/brake control unit determines an internal parameter based on an external control signal and an operation state of a plant. The compensation unit generates a driving control signal based on an error signal supplied from the plant and the internal parameter, and supplies the driving control signal to the plant. The plant performs a steady-state operation during a first operation mode and a target moving operation during a second operation mode based on the driving control signal.

Abstract: A controller estimates Coulomb friction itself together with inertia and viscous friction, and reduces the influence of the Coulomb friction on the accuracy of the estimated inertia. In addition, the controller estimates inertia, viscous friction and Coulomb friction simultaneously with sequential adaptation in which a Fourier transformer is not used but an inverse transfer function model is used in order to minimize the estimated error. Data sampled for a predetermined time need not be accumulated, as a result, a large amount of data memory is unnecessary.

Abstract: There is provided an optical disc reproducing method capable of reproducing a non-finalized DVD+R. When a seek operation is performed from a present address on the non-finalized DVD+R to an outer circumferential side target address, the outer circumferential direction total jump number of tracks is calculated from a difference between the present address and the target address. When a first condition is satisfied in which the present address is in an inner circumferential zone, the target address is in a second outer circumferential zone, and the outer circumferential direction total jump number is 701 to 2500, the jump number of tracks is set to 340 smaller than the outer circumferential direction total jump number, and a traverse seek using a moving mechanism to move an optical pickup in a radius direction by 340 is performed.

Abstract: Improved control of spindle speed during optical media seek operations is provided by adjusting the spindle motor speed during the actual optical pickup unit movement. In response to receiving a seek instruction to move an optical pickup unit to a target position, the current signal frequency corresponding to a current spindle motor speed may be determined. A target signal frequency corresponding to a desired spindle motor speed at the target position may also be computed. Thereafter, the current spindle motor speed may be adjusted towards the desired spindle motor speed prior to the optical pickup unit reaching the target position.

Abstract: An optical disk apparatus according to the present invention includes a spindle motor that rotates an optical disk on whose information recording surface a plurality of addresses is recorded, an optical pickup that records/reproduces an information signal on/from the information recording surface of the optical disk rotated by the spindle motor, an strobe light-emitting unit that irradiates a label surface of the optical disk with light, and a control unit that causes the strobe light-emitting unit to emit light based on an address selected from the plurality of addresses as a reference address and a reference signal readable from the optical disk.

Abstract: An object of this invention is to measure the tilt quantity of, and perform a tilt control on, an optical disc accurately without depending on the rotation control method. An optical disc drive includes: a motor for rotating an optical disc; an optical system for irradiating the optical disc with a light beam; a moving mechanism for moving the optical system along the radius of the optical disc; a focus control section for controlling movement of the optical system perpendicularly to the optical disc based on drive values, thereby focusing the light beam onto a storage layer of the optical disc; and a tilt control section for measuring the tilt quantities of the storage layer at multiple different radial locations on the optical disc based on drive values for the respective radial locations when the focus control section focuses the light beam there.

Abstract: Information indicative of the placement of spindle motor components may be obtained and used to provide a correction to one or more BEMF-derived attributes used to control the spindle speed. In some implementations, first and second signals indicative of BEMF of different stator windings may be used to determine a speed-related characteristic. The speed related characteristic may be used to determine an error amount, which may be used to determine a correction factor to control the speed of the spindle motor.

Abstract: According to one embodiment, an optical recording medium is provided in which interlayer crosstalk is low and in which stable and high-quality recording characteristics can be obtained. To this end, an optical recording medium comprises a first recording part which includes a first recording layer and a first light reflecting layer and which is disposed on a side closer to a light receiving surface, and a second recording part which includes a second recording layer and a second light reflecting layer and which is disposed on a side farther from the light receiving surface, the first recording part and the second recording part being stacked, wherein the thickness of the second light reflecting layer is larger than the thickness of the first light reflecting layer.

Abstract: An optical disk playback device includes a control means (an LSI 5 for system control) for performing a track search according to contents information, comparing a current track start point position at the time after performing the track search with a target track start point position, when the comparison result shows that they differ from each other, setting up a new target track start point position by performing a predetermined arithmetic operation, then performing a track search again, and, when a new current track start point position at the time after performing the track search again matches the set-up new target track start point position, starting a playback from the new current track start point position.

Abstract: A recording and/or reproducing apparatus, medium, and method controlling a write speed of a disk drive. The method may includes measuring a predetermined disk quality evaluating factor affecting a servo control performance in multiple areas of a disk, determining an optimal write speed of the areas of the disk corresponding to the disk quality evaluating factor, and controlling a rotation speed of the disk at an optimal write speed of a corresponding area of the disk, depending on a position of the disk in which writing is to be performed, in a writing mode.

Abstract: An optical disk is equipped with a predetermined mark. A frequency generator outputs an FG pulse of frequency corresponding to the rotational speed of a spindle motor used for rotationally driving the optical disk. The edge of the FG pulse detected by an edge detection section is counted by an FG counter. An angle counter measures the duration of a time from appearance of an edge of the FG pulse until a point in time when the mark affixed to the optical disk 1 is detected. A count value of the FG counter, which has been acquired at the point in time when the mark is detected, and a count value of the angle counter are saved. In a case where a visible image is rendered, encoding of a visible image to be rendered is started when the count value of the FG counter and the count value of the angle counter have become equal to the respective saved values.

Abstract: A focus servo apparatus for an optical disc apparatus including an objective lens to converge laser beam on an information recording surface of an optical disc, and an actuator to move the objective lens in a focusing direction crossing the information recording surface, the focus servo apparatus comprising: a retaining unit configured to retain control data for driving the actuator; and a setting unit configured to set the control data retained by the retaining unit as initial data for driving the actuator, in the case of driving the actuator, to detect a position of the objective lens where the laser beam is focused on the information recording surface, as a target position when performing focus servo.

Abstract: According to one embodiment, an information processing apparatus, has a reading unit which, if a transfer delay address is found, stores data in the transfer delay address, in a memory, and stores data in a range from the transfer delay address to an additional address located at an outer periphery in a certain distance and which, if the address to be read on the optical disc is present in the transfer delay address, reads data corresponding to the address to be read as stored in the memory, and a control unit which, if the address to be read on the optical disc is present in the additional address, reads the data corresponding to the address to be read as stored in the memory, by the reading unit, and increases a rotation rate of the optical disc up to a predetermined number of revolutions.

Abstract: An information recording carrier according to one embodiment has minute pattern including plural grooves or lands formed to be substantially in parallel and adjacent each other and comprises a supporting body having the minute pattern, a recording layer formed on the minute pattern formed on the supporting layer and a light transmission layer formed on the recording layer. The minute pattern is formed under a relation of P<?/NA, where a pitch of each groove or land is P, a wavelength of a laser beam is ? and a numerical aperture of an objective lens is NA. The plural grooves or lands have at least a wobbling region and data is recorded wobblingly in the wobbling region by frequency shift modulation. A phase relation between a high frequency portion and a low frequency portion composing the frequency shift modulation is ±(?/20.5) to ±(?/0.75). The data is also recorded wobblingly in the wobbling region by bi-phase modulation.

Abstract: An optical disc drive apparatus has: a rotation angle counter cleared when the number of pulses in a frequency multiplied FG signal has reached a value corresponding to one rotation of the disc; a switching sector detector detecting polarity switching locations based on the output signal of an RF processor to clear the rotation angle counter; a switching window signal generator generating a switching window signal having a predetermined width based on the count value; a timing signal generator generating a timing signal for each sector based on the output signal of the RF processor; and a polarity switching signal generator generating a polarity switching signal based on the switching window signal and the timing signal.

Abstract: An optical drive servo control system comprises: an optical pickup, for accessing an optical disc and generating an optical signal; a spindle motor, for rotating the optical disc and outputting a FG signal and a spindle motor synchronous signal; a frequency-multiplied FG signal generator, for generating an actual frequency-multiplied FG signal after receiving the FG signal, the spindle motor synchronous signal, a reference clock signal, and a frequency-multiplier value; and, a servo control unit, for controlling the spindle motor and the optical pickup, and compensating a run-out error of the optical disc according to the actual frequency-multiplied FG signal; wherein the frequency-multiplied FG signal generator calculates an ideal frequency-multiplied FG signal according to the reference clock signal and the frequency-multiplier value, and a positioning error between the ideal frequency-multiplied FG signal and the actual frequency-multiplied FG signal is less than half of a period of the reference clock sig

Abstract: An apparatus includes a moveable arm for positioning an optical transducer adjacent to a storage medium, a light source, and an elliptical or ellipsoid shaped mirror mounted for reflecting light from the light source to the optical transducer. The elliptical mirror can be positioned on an ellipse, the moveable arm can pivot about an axis passing through a first focus of the ellipse, and the light source can direct light from a point on a second axis passing through a second focus of the ellipse to the elliptical minor. The light source can include a fixed laser and a moveable mirror mounted to pivot about the second axis or a moveable laser mounted to pivot about the second axis. A method performed by the apparatus is also provided.

Abstract: Plural grooves or lands formed in an information recording carrier include at least a wobbling region and data is recorded wobblingly in this wobbling region by frequency shift modulation while recorded digitally with a single or multiple waves as a channel bit.

Abstract: Plural grooves or lands formed in an information recording carrier include at least a wobbling region and data is recorded wobblingly in this wobbling region by frequency shift modulation while recorded digitally with a single or multiple waves as a channel bit.

Abstract: A method for controlling the recording speed of a multi-layered optical disc divides a multi-layered optical disc into a plurality of zones with each zone having a corresponding recording speed. It is then determined which zones need the recording speed to be reduced according to the quality of the optical disc. When the optical drive records data onto an inferior quality zone, it reduces the recording speed to guarantee the reliability of recorded data and enhance recording quality. When the optical drive records data on the next recording layer and has passed the zone that corresponds to the inferior quality zone of the previous recording layer, it increases the recording speed. Thereby the method ensures both quality and efficiency. Furthermore, the recording speed of each subsequent zone of the next recording layer corresponds to the recording speed of each previous zone of the recording layer.

Abstract: A disc drive (1) comprises first clamping means (5) and second clamping means (7) for supporting an optical disc (3) that is to be played in the disc drive (1). Drive means (9) is provided for rotating the optical disc (3) relative to optical means (11) for writing data to, or reading data from, the optical disc (3). The disc drive (1) further comprises a data storage medium (13) for storing data such as embedded software for controlling the operation of the disc drive (1). The data storage medium (13) is permanently located in the disc drive (1), thereby being permanently available for controlling the operation of the disc drive (1). The data storage medium (13) is located coaxially with optical disc (3) that is to be inserted into the disc drive (1) for playback. The data storage medium (13) is also positioned such that, during playback of a normal optical disc (3), the data storage medium is located on the reverse side of the optical disc (13), i.e. the non-optical side of the optical disc (3).

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: An optical system has an objective lens condensing a light beam from the light source on a recording layer selected from the plurality of recording layers of the optical disk, and leading a returning light beam reflected by the selected recording layer to a predetermined position; an aberration detecting part detecting a physical amount relative to spherical aberration based on an output signal of the photodetector; an aberration correcting part correcting the spherical aberration based on the physical amount; and a processing device carrying out at least the information reproduction o from among information recording, information reproduction and information deletion with the use of the output signal of the photodetector.

Abstract: Plural grooves or lands formed in an information recording carrier include at least a wobbling region and data is recorded wobblingly in this wobbling region by frequency shift modulation while recorded digitally with a single or multiple waves as a channel bit.

Abstract: There is provided an information recording/reproducing apparatus for recording or reproducing an information to or from an information recording medium having a plurality of recording layers stacked on a substrate which can always perform stable spindle rotation control irrespective of an error of a desired frequency value or the like, and which includes an optical head for recording or reproducing an information to or from the recording layers by use of an optical beam; a spindle motor for rotating the recording medium; and a drive voltage holding circuit for holding a drive voltage of the spindle motor when the optical head performs switching between the recording layers for recording/reproducing.

Abstract: Plural grooves or lands formed in an information recording carrier include at least a wobbling region and data is recorded wobblingly in this wobbling region by frequency shift modulation while recorded digitally with a single or multiple waves as a channel bit.

Abstract: Plural grooves or lands formed in an information recording carrier include at least a wobbling region and data is recorded wobblingly in this wobbling region by frequency shift modulation while recorded digitally with a single or multiple waves as a channel bit.

Abstract: An information recording carrier according to one embodiment has minute pattern including plural grooves or lands formed to be substantially in parallel and adjacent each other and comprises a supporting body having the minute pattern, a recording layer formed on the minute pattern formed on the supporting layer and a light transmission layer formed on the recording layer. The minute pattern is formed under a relation of P<?/NA, where a pitch of each groove or land is P, a wavelength of a laser beam is ? and a numerical aperture of an objective lens is NA. The plural grooves or lands have at least a wobbling region and data is recorded wobblingly in the wobbling region by frequency shift modulation. A phase relation between a high frequency portion and a low frequency portion composing the frequency shift modulation is ±(?/20.5) to ±(?/0.75).

Abstract: Plural grooves or lands formed in an information recording carrier include at least a wobbling region and data is recorded wobblingly in this wobbling region by frequency shift modulation while recorded digitally with a single or multiple waves as a channel bit.

Abstract: A method and apparatus for controlling a maximum rotational speed of a recording medium, are discussed. The method according to an embodiment of the present invention includes determining an imbalance error of the recording medium, and variably setting a maximum rotational speed of the recording medium based on the determined imbalance error.

Abstract: An optical disc apparatus, as a learning operation before a recording or reproducing operation, rotates an optical disc at a first speed to read PID information, discriminates between lands and grooves of the optical disc, detects switching positions between lands and grooves, sets a rotation angle position of tracking pull-in of an objective lens of a time length that allows the PID information to be stably read, with respect to the switching position, and stores the set position information of tracking pull-in as learning result information. During recording or reproducing, the optical disc apparatus rotates the optical disk at a second speed higher than the first speed, pulls in the objective lens for tracking based on the stored position information of tracking pull-in, reads PID information, and performs the recording or reproducing operation while discriminating between lands and grooves and detecting switching positions between lands and grooves.

Abstract: An optical disk apparatus is disclosed which can suppress excessive reduction of recording speed on the inner side of a disk and that can assure quick response of accessing operation.

Abstract: The optical disk recording/reproduction device is provided with an information recording area search means, comprising, a moving means which detects the presence and absence of information and return moves an optical pickup from inward to outward or from outward to inward direction of an optical disk, and a stopping means which stops the movement of optical pickup if an information recording area is detected in the movement of optical pickup. If the existence of information cannot be confirmed at a re-zeroing position in the initial operation, the optical pickup is moved to the inward of optical disk at a normal velocity; when the optical pickup passes through the information recording area, it is braked and stopped. If the existence of information can be confirmed at the stop position, the flow is shifted to normal reproduction; if it cannot be confirmed, the optical pickup is determined to pass through the information recording area and stop, returned from the stop position and moved outward at a low speed.

Abstract: An access method for use when switching from recording into an optical disk to reproduction from the optical disk or vice versa is disclosed that comprises a step of calculating a rotating speed n2 of a motor for rotating the optical disk given that linear velocities in a first access position before the switching and a second access position after the switching are equal, a step of determining whether n2 satisfies a pair of expressions n2>n0 and n2>n1 or a pair of expressions n2<n0 and n2<n1 where n0 and n1 are rotating speeds of the motor before and after the switching, a step of changing a control mode from CLV to CAV and the rotating speed from n0 to n1 if one of the pairs of expressions is satisfied, and a step of shifting a position to be accessed from the first access position to the second access position.

Abstract: In a case where an image of a density that is uniform over a substantially whole area of an optical disc (200) is to be formed, a servo circuit (138) controls the rotation speed of a spindle motor (130) to be constant, and an ALPC circuit (162) controls the current level of a drive signal Li so that the laser power is constant. In this case, a main control section (170) sets the movement distance of an optical pickup (100) to be larger in the inner peripheral side where the line width of the image is larger, and that of the optical pickup (100) to be smaller in the outer peripheral side where the line width is smaller. The main control section (170) sends to a the motor driver (142) instructions for moving the optical pickup (100) by a movement distance which is determined on the basis of the setting.

Abstract: An information recording carrier according to one embodiment has minute pattern including plural grooves or lands formed to be substantially in parallel and adjacent each other and comprises a supporting body having the minute pattern, a recording layer formed on the minute pattern formed on the supporting body and a light transmission layer formed on the recording layer. The minute pattern is formed under a relation of P<?/NA, where a pitch of each groove or land is P, a wavelength of a laser beam is ? and a numerical aperture of an objective lens is NA. The plural grooves or lands have at least a wobbling region and data is recorded wobblingly in the wobbling region by frequency shift modulation. A phase relation between a high frequency portion and a low frequency portion composing the frequency shift modulation is ±(?/20.5) to ±(?/0.751).

Abstract: In a case where an image of a density that is uniform over a substantially whole area of an optical disc (200) is to be formed, a servo circuit (138) controls the rotation speed of a spindle motor (130) to be constant, and an ALPC circuit (162) controls the current level of a drive signal Li so that the laser power is constant. In this case, a main control section (170) sets the movement distance of an optical pickup (100) to be larger in the inner peripheral side where the line width of the image is larger, and that of the optical pickup (100) to be smaller in the outer peripheral side where the line width is smaller. The main control section (170) sends to a the motor driver (142) instructions for moving the optical pickup (100) by a movement distance which is determined on the basis of the setting.

Abstract: An optical disk apparatus for controlling two optical pickups in an optimized way in response to operation modes for rotating the optical disk. When receiving a request for seeking one optical pickup from a HOST, a CPU judges whether to move the other optical pickup synchronously to satisfy positional restriction of the two optical pickups. Furthermore, when operating one optical pickup upon, for example, a read request. from the HOST, the CPU judges whether to move the other pickup to follow.

Abstract: There is provided an information recording device for recording record information onto an information recording medium having a plurality of recording layers. The information recording device includes: write elements capable of writing record information into the recording layers; control elements for controlling the write elements to write first boundary information or second boundary information (107a-0) having a smaller recording capacity than the first boundary information at the end of record information recorded in one of the recording layers; and detection elements for detecting an empty capacity of the data area in that recording layer. The control elements controls the write elements to write the first boundary information at the end if the empty capacity is equal to or greater than a first threshold value and the second boundary information at the end if the detected empty capacity is smaller than the first threshold value.

Abstract: A method for compensating for a position error in an optical disc drive (ODD) is provided. The method compensates for a position error generated by a step error associated with a motor which moves an optical pickup unit across a surface of an optical disc. Error data associated with each step of the motor is stored in a memory unit of the ODD, and compensation for the related position error is accomplished by compensating for a track-direction movement of an actuator. The method is particularly useful when conducting a label-printing operation, in that it allows the label printing operation to be performed without generating position errors, gaps, or overwrites on a label surface of the disc, thus enhancing the quality of a label-printing operation and the resulting label.

Abstract: An optical drive servo control system comprises: an optical pickup, for accessing an optical disc and generating an optical signal; a spindle motor, for rotating the optical disc and outputting a FG signal and a spindle motor synchronous signal; a frequency-multiplied FG signal generator, for generating an actual frequency-multiplied FG signal after receiving the FG signal, the spindle motor synchronous signal, a reference clock signal, and a frequency-multiplier value; and, a servo control unit, for controlling the spindle motor and the optical pickup, and compensating a run-out error of the optical disc according to the actual frequency-multiplied FG signal; wherein the frequency-multiplied FG signal generator calculates an ideal frequency-multiplied FG signal according to the reference clock signal and the frequency-multiplier value, and a positioning error between the ideal frequency-multiplied FG signal and the actual frequency-multiplied FG signal is less than half of a period of the reference clock sig

Abstract: An information recording carrier in one mode has minute pattern including plural grooves or lands formed in parallel and adjacent each other and comprises a supporting body having the minute pattern, a recording layer formed on the minute pattern, and a light transmission layer formed on the recording layer. The minute pattern is formed under a relation of p<?/NA, where a pitch of each groove or land is P, a wavelength of a laser beam is ? and a numerical aperture of an objective lens is NA. The plural grooves or lands have at least a wobbling region where data is recorded wobblingly by frequency shift modulation. A phase relation between the high and the low frequency portion composing the frequency shift modulation is ±(?/2.5) and the high and the low frequency portion are continuous in phase at a border between the high and the low frequency portion.

Abstract: A system and method of switching the control modes of spindle motor are described. The switch system comprises a first control module, a second control module and a switch controller. The first control module electrically coupled to the spindle motor and the OPU controls the spindle motor to be operated in a present mode. The second control module is electrically coupled to the spindle motor to control the spindle motor to be operated in the transition mode between the present mode and the target mode. The switch controller electrically coupled to the first control module, the second control module and the spindle motor receives a present feedback signal associated with the rotation of spindle motor to generate a first switch signal. Furthermore, the switch controller receives a target indicative signal associated with the information on the optical storage medium to generate a second switch signal.

Abstract: A method for controlling the rotation speed of an optical storage device. In the first mode, a first signal is produced, and in the second mode, a second signal is produced. In one mode, a first pulse of a first voltage and a second pulse of a second voltage are sent to the motor, which causes the motor to produce a first armature current and a second armature current. In another mode, a DC signal of a third voltage is produced, which causes the motor to produce a third armature current. The armature currents are detected, and test voltages are outputted. The first and second voltages, and the first and second test voltages are used to find a motor coefficient. The third voltage, the motor coefficient, and the third test voltage are used to calculate a motor rotation speed. The calculated speed is used to control the real motor speed.

Abstract: An information medium includes a lead in area and a data area capable of recording an arbitrary information signal. The lead in area has a recordable portion where an information signal can be recorded. The recordable portion of the lead in area has an identifier I1 defining a recording speed applicable when recording an information signal in the data area. This increases accuracy defining the recording speed.

Abstract: The present invention shortens a time to be elapsed from a recording interruption to a recording restart, thereby realizing a reliable recording restart. In one embodiment, an optical disk apparatus comprises an optical pickup and a processor, which includes a reproduction system circuit, a speed information detection circuit, and a position detection circuit. The reproduction system circuit is configured to generate a reproduction signal used in restarting recording of the optical disk after an interruption, based on the electrical signal from the optical pickup and setting values. The speed information detection circuit is configured to detect speed information before or after an interruption of a recording on the optical disk based on the electrical signal from the optical pickup. The position detection unit is configured to detect a recording restart position and a current position of the optical disk.