Abstract: Provided are a method and apparatus for removing vibration due to the imbalance of weight of a disc in a disc drive, in which the allowable high multi-speed of a disc is determined based on the allowable amount of vibration in the disc drive and the disc drive is actuated within a range of the allowable high multi-speed. The method includes detecting the amount of vibration corresponding to the degree of imbalance of the weight of a disc inserted into the disc drive and increasing a set high multi-speed of the disc drive until the amount of vibration reaches an allowable amount of vibration with respect to the disc drive. Accordingly, vibration in a disc drive can be controlled such that a user cannot perceive it and damages to the disc drive due to the vibration can be minimized.

Abstract: A method used in a CD-R/W drive for coordinating the writing and reading speeds of a CD-R/W drive is disclosed. With the aid of the method, the writing speed of the CD-R/W drive is able to be adjusted, and thus a more stable writing operation is obtained. In the method, if the time(s) that the buffer has been cleaned up is/are not larger than the predetermined value, the CD-R/W drive will write data to the CD-ROM at its highest speed. On the contrary, if the time(s) that the buffer has been cleaned up is/are larger than the predetermined value, the CD-R/W drive will slow down stepwise from the current speed to a lower speed. To accomplish the invention, the CD-R/W drive is either controlled by computer programs or by a programmably pre-written control chip that is installed in a control circuit inside the CD-R/W drive itself.

Abstract: A method of elimination of interference created on CDR/W run-out motors on sledge servers, especially for the elimination of interference created by the run-out of the combination of CDR/W spindle motor on track-seeing servers, where a general evaluating device is provided linking the controller output of the data access module driven by the sledge server motor and the final track signal output, including a speed evaluating device and a run-out evaluating device that may have access to the run-out factor of the CDR/W motor and the CD in the data access module for evaluation of the elimination function of the speed and the run-out tolerance, so that the run-out evaluating device could emit run-out compensation signals for amplification by a relay amplifier and the spindle motor synchronized signal before a negative feedback calculation by playing the final output signal of the module, with access to a play control signal for the elimination of run-out to the CDR/W sledge server, so that the CD may be read, wri

Abstract: The speed of a CD drive that is coupled to a host can be adjusted by the steps of receiving a command from the host, calculating the processing speed required by the host for executing the received command, and adjusting the processing speed of the CD drive if the required processing speed of the host is either greater than or less than the current processing speed of the CD drive.

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: A method for reading data from an unbalanced disk in a disk drive is disclosed. The method includes the steps of measuring a degree of unbalance of the disk while starting up a rotation of the disk, determining a suitable rotating speed for error-free reading (e.g., a maximum error-free reading speed) corresponding to the measured degree of unbalance, based on a previously stored relationship between degree of unbalance and suitable rotating speed, and beginning a reading operating while rotating the disk at the determined rotating speed. In accordance with the method, it is possible to suppress an unbalanced disk from vibrating, thereby achieving a stable data reading from the disk.

Abstract: In an optical recording method and apparatus of the present invention, a driving power is applied to a light source to control emission of a light beam to a recording layer of an optical storage medium, the driving power including a sequence of mark and space portions, each mark potion having a pulse width that corresponds to a multiple of a period T of a write clock. A multi-pulse waveform of each mark portion of the driving power includes a front-end portion, a multi-pulse portion and a tail-end portion, the front-end portion having a first pulse width t1 with a high-power write level Pw and starting from a middle-power erase level Pe, the multi-pulse portion including write pulses each having a second pulse width t2 with the write level Pw and a third pulse width t3 with a low-power base level Pb, the multi-pulse portion having a duty ratio z=t2/(t2+t3), and the tail-end portion having a fourth pulse width t4 with the base level Pb and ending at the erase level Pe.

Abstract: When a deviated gravity disc is reproduced at a higher rate with the disc reproducing apparatus, an excessive vibration is generated and this vibration gives adverse effect on the disc reproducing apparatus and peripheral components/apparatuses, and/or may represent an annoyance to a user. A vibration information detector for detecting vibration of the disc reproducing apparatus or a deviated gravity information detector for detecting amount of gravity deviation of disc is provided, and as a result of such detection of an imbalance (i.e., excessive vibration or mass eccentricity), and a reproducing rate switching control controls sets and limits the reproducing rate of the disc reproducing apparatus to a substitute speed which is lower or higher than a normal reproducing speed.

Abstract: In a method and apparatus for controlling the power of a laser beam in an optical recording system that includes a laser light source, an optical detector detects a reflected write pulse that is a reflection of an incident recording light signal from the optical recording medium, and a signal generating device generates a mark formation effectiveness (MFE) signal according to the reflected write pulse. A laser power compensation circuit includes a filter for filtering the MFE signal so as to result in a first component, and a combiner for combining the first component and the MFE signal so as to result in a second component. The laser power compensation circuit controls laser beam power of the laser light source according to the first and second components for optimum information recording.

Abstract: An optical disc player having an optical pickup records and retrieves information on an optical disc while the optical disc is rotating. A rotation pulse is generated each time the optical disc rotates through a prescribed angle. A rotation frequency data representing a frequency of the rotation pulse is also generated. A servo processor performs servo processing for rotation control on the optical disc in accordance with the rotation frequency data. A sampling pulse generator performs computational processing on an input data signal to generate a sampling pulse. The sampling pulse generator also corrects the rotation frequency data based on a phase error between the sampling pulse and the rotation pulse to use a corrected rotation frequency data as the input data signal. Another servo processor performs servo processing for repetitive control on the optical pickup using the sampling pulse.

Abstract: A system and method for controlling operation of a motor system that addresses the design challenges for the small form factor optical disk system. The control system can be operable to obtain digital feedback from a spin motor. The present invention includes detecting data representing a position on an optical medium and determining a detection rate; comparing the detection rate to a reference rate to provide an error rate; generating an output command in response to the error rate to provide a drive output which commands a voltage applied to a spin motor to adjust the spin speed of said spin motor.

Abstract: A reproducer can enhance detection accuracy with respect to a rotational motion according to a scratch operation and properly change a reproducing speed of a recording medium. A turntable of a scratch operating part comprises a disk-shaped mounting plate, which is made from metal, fixed on the upper end of a bushing, a ring-shaped grooved member fixed on a marginal area of the under surface of the mounting plate with mounting bolts, and a marginal member fixed on an outer area of the ring-shaped grooved member. A disk has a disk surface on rollers provided on the top surface of the turntable and a ring-shaped detected part located around an outer circumference of the disk surface and projecting from the under surface of the disk. A light receiving element supplies a signal with a frequency proportional to a period in which a concave part and a convex part pass according to the rotational speed of the disk.

Abstract: The present invention relates to method and apparatus for controlling disk reproduction speed to extend an operable time of a portable device such as a notebook computer using a battery as a power source. A method for adjusting a disk reproduction speed based on a remaining battery energy according to the present invention, at the part of a portable device such as a notebook computer, detects an amount of the remaining battery energy, and sends a data indicating the detected amount of the remaining battery energy to a connected disk device, and, at the other part of a disk device, reduces a disk reproduction speed based on the data sent by the portable device. The method and apparatus for controlling disk reproduction speed according to the present invention can extend an operable time of the portable device whose operating power is supplied from an equipped battery whose storage capacity is restricted.

Abstract: This invention provide a recording/reproducing device for a recordable optical disc. The recordable optical disc has a management data area in which data related to intrinsic physical characteristics and data related to linear recording density are recorded, and a data recording area in which recording data is recorded. A rotational driving unit rotationally drives the optical disc and has a speed detection unit for detecting rotation of the optical disc. A temperature detection unit detects the temperature on the periphery of the optical disc. A control unit calculates optimum power of a laser beam cast onto the optical disc on the basis of the data related to intrinsic physical characteristics and the data related to linear recording density which are read out by a head unit, detection data from the speed detection unit, and detection data from the temperature detection unit, and control the head unit on the basis of the result of the calculation.

Abstract: The present invention provides an optical disc apparatus capable of rotating an optical disc with high speed while enabling reduced current consumption. The optical disc apparatus comprises a spindle motor for rotating the optical disc and a thread motor for driving an optical pick-up. When a command is received while the spindle motor is driven, a controller delays operation of the thread motor for a predetermined duration to allow operation of the spindle motor rather than immediately activating the thread motor. After the predetermined duration has elapsed, the controller activates the thread motor and halts the operation of the spindle motor. The predetermined duration may be either a fixed value or a variable value established so as to become smaller as rotation speed of the optical disc increases.

Abstract: A drive current or a drive voltage is controlled corresponding to change of load by sampling the drive current or drive voltage of a motor to move an optical pickup and then detecting change of the sampling signal as change of the optical pickup when it is moved. Moreover, change of the sampling signal is obtained from a difference of the sampling signals by comparing these sampling signals at the first and second points. Comparison of these sampling signals is conducted in unit of drive pulse.

Abstract: The present invention relates to a method and an apparatus for controlling the rotation of a turntable, in order to move a disk mounting portion selected among a plurality of disk mounting portions installed on the turntable to a pickup side by a key input signal of a user which includes rotating the turntable by supplying a driving voltage to a turntable driving motor, sensing a rotational velocity of the turntable and the extract output delay time Td of the driving voltage of the motor for stopping the pertinent disk mounting portion at a reproducing position on the basis of the sensed rotation velocity, and cutting off the driving voltage output of the turntable driving motor after confirming the approach of the pertinent disk mounting portion to a reproducing position and confirming the output delay time.

Abstract: A method for controlling speed of a spindle motor of an optical disc player is provided by the invention. The method provided accept a on-line or real-time control signal asserted by a user and determine whether a property within the control signal meets a predetermined criterion. If the predetermined criterion is met, the speed of the spindle motor is set to another value. The speed change involved may be in either positive or negative direction. In the preferred embodiment, duration of the control signal is selected as the parameter while making the decision.

Abstract: The present invention provides an information disc-recording/playback apparatus which includes a track cross detection means (112), a track cross direction detection means (113), a rotation angle detection means (114), and a count means (115), detects the track pitch of a disc, evaluates the vibration amount, or vibration speed, or vibration acceleration considering the track pitch of the disc, and determines a maximum rotation speed that is lower than the allowable vibration amplitude, vibration speed, or vibration acceleration of the information disc recording/playback apparatus; as well as a vibration detection method for the information disc recording/playback apparatus.

Abstract: A disc drive includes a disc mounted to a rotatable spindle, a motor coupled to the spindle, and motor control circuitry. The motor has a motoring mode in which it rotates the spindle and a braking mode in which is decelerates the rotating spindle and generates power. The motor control circuitry is adapted to control the modes of the motor. The disc drive also includes an auxiliary power output that is generated while operating the motor in the braking mode. The auxiliary power output is made accessible to electronic components that are collateral to the disc drive.

Abstract: An optical pickup is described with an electronically adjustable beam spot size for reading optical media. Two proximal light sources are impinged on a selected track of the media and the reflected light is registered by photodetector arrays. The electrical signal generated from the leading detector is delayed, based on a distance between beams and the speed of the media, to achieve a desired amount of temporal coincidence with the electrical signal associated with the lagging beam. The electrical signals are combined, such as in a multiplier circuit, to create a third electrical signal whose response to a data bit can be adjusted to a shorter duration than the responses from either first or second beams. Therefore, the effective spot size may be electronically controlled, wherein light sources of longer wavelengths may be utilized, and optical data storage systems may be configured for reading media having different optical characteristics.

Abstract: A control method for a rotation speed is used in an optical disc drive. When the angular velocity of the optical disc in rotation is fixed and the rotation direction is the same as the direction of the torque, then a breaking torque, having the same magnitude as the rotational torque but in the opposite direction, is applied to cause the rotation of the optical disc to cease. In other situation, a fixed rotational torque of the same magnitude as that of the angular velocity is first applied to cause the optical disc to have a fixed angular velocity. Then, a breaking torque having the same magnitude as the fixed rotational torque but in the opposite direction is applied to cause the rotation of the optical disc to cease. In this manner, no matter what rotation speed of the optical disc is, the rotation of the optical disc can always be ceased by a fixed period of time.

Abstract: An optical disc drive according to an embodiment of this invention includes a light-receiving section for receiving light, a conversion section for converting the light received by the light-receiving section into an electrical signal, a generation section for generating a slewing rate control signal, and a signal processing section for processing the electrical signal using the slewing rate control signal.

Abstract: A disk drive capable of producing the effect of a balancer even in a variety of reproduction and recording speeds without causing problems owing to the balancer, comprising a balancer in which magnetic balls 1 movably accommodated inside a damper 6 cancel any imbalance amount of a disk 5, and a detection section 14 provided near the clamper 6 to detect the behavior of the magnetic balls 1.

Abstract: A device for stabilizing the rotating speed of a record player has a passive element fitted on the same shaft of a rotating, disk, which activates a record to rotate together. The passive element is formed with a surface expanding outward from a center portion fitted with a shaft and having its outer annular portion engraved with annular minute net holes. A sensor facing the positions of the net holes is provided under a printed circuit board for detecting the change of the shifting speed of the net holes. The signal data detected by the sensor is fed to a micro-processor to carry on operation, and after that, the value of the signal data is transmitted back and automatically modulates the voltage supplied to the rotating disk to let the rotating disk and the record rotate steadily.

Abstract: To provide a recording and reproducing device for an optical disc. There are included a spindle motor for rotating the optical disc, a mechanical chassis for fixing the spindle motor, a fixing member provided on the spindle motor, and a bonding member for fixing the spindle motor to the mechanical chassis by bonding the fixing member to the mechanical chassis in a state in which attitude adjustment and positioning are performed.

Abstract: The present invention relates to an apparatus of measuring how much an eccentricity affects each phase of a disk and controlling disk tracking based on the each effect rate. The present apparatus with disk phase identifying means stores information on dense/sparse state of a tracking error (TE) signal in connection with characteristic of an output signal from said means while a tracking servo is inactivated, and, in data reproduction mode, it identifies a current disk phase based on characteristic of the output signal from said means, and adjusts tracking characteristic of the tracking servo based on the stored information in connection with signal characteristic in order to compensate effect rate of eccentricity on the identified disk phase. Through minute adjustment of servo characteristic for each disk phase, error range of TE signal to track in real time is reduced, whereby, tracking for an eccentric disk becomes easier and more reliable.

Abstract: The optical disk player is capable of showing the change of the data writing velocity and/or the changed writing velocity to a user. The optical disk player comprises: means for indicating a change of data writing velocity. With this structure, the user can know the fact of changing the data writing velocity without executing any operation.

Abstract: Servo control circuitry 300 includes a digital to analog converter 402 for converting digital servo control data into a pulse width modulated signal. A first conductor transmits the pulse width modulated signal to an external device 409. A second conductor transmits a reference signal derived from the clock signal to external device 409, external device 409 differentially receiving the pulse width modulated signal with respect to the reference signal.

Abstract: The method of controlling laser power of an optical disk player, in which liner velocity of writing data is accelerated, by stages, toward an outer edge of an optical disk, is characterized in that a laser power for writing data is changed when the liner velocity is changed. With this method, the laser power for writing data is changed when the liner velocity is changed, so quality and reliability of the written data can be improved.

Abstract: There is provided an optical disk drive for playing or playing and recording an optical disk, and a method for controlling the optical disk drive, wherein, while the rpm of a spindle motor (11) is changed, the spindle motor (11) is controlled according to FG servo by a second spindle motor controller (23), and tracking servo by a tracking controller (18) is turned off.

Abstract: In an information recording medium, positions of pits are modulated in a direction intersecting a direction of reading of pits, so that a predetermined information is recorded. In this information recording medium, the whole of the predetermined information or a part of the predetermined information is randomized through the used of spread spectrum.

Abstract: The present invention provides a control system of following a follow target position. A control system has a disturbance observer for obtaining a disturbance force estimation value and a speed estimation value as estimation values of a disturbance force and a speed as a speed to be controlled by using an actuator control signal cont and a zero follow position which can be observed. Since the disturbance force estimation value and speed estimation value are fed back.

Abstract: This invention provides method and apparatus for controlling a reproduction speed of an optical disk, which detects the condition of an optical disk and changes the reproduction speed automatically to a pre-determined speed corresponding to the detected disk condition. The method according to this invention comprises the steps of detecting the condition of an optical disk through the characteristics of an RF signal reproduced from the optical disk; adjusting the reproduction speed of the optical disk to a pre-determined speed appropriate for the detected disk condition.

Abstract: A circuit records data on an optical disk while the disk is rotated at a constant angular velocity. A velocity detector determines a velocity of a rotating disk as a detected velocity. A memory stores sets of write signal control values, and each set of write signal control values is associated with a predefined velocity. A control circuit retrieves at least two sets of write signal control values based on the detected velocity and selected predefined velocities of the sets of write signal control values. A write strategy circuit generates one or more write signals in accordance with the write signal control values of the selected set and write data. The control circuit designates a selected set of write signal control values from the at least two sets of write signal control values while generating the one or more write signals.

Abstract: An information recording apparatus that records information with a substantially constant linear density in a circumferential direction of a recording medium having a disk shape, includes variable velocity recording control means, recording power modification means, recording power storage means, and initial recording power value setting means.

Abstract: A protection method that prevents optical disk drives from Laser leakage is provided. First, determine whether switch detector has generated a close-status signal of the optical disk drive or not: if yes, then forward kick the spindle motor. Next, feed back the actual revolving speed of the spindle motor. Then, determine whether the actual revolving speed is lesser than the empty-tray revolving speed or not: if yes, then emit Laser rays to read CD data, otherwise, halt emitting Laser rays and perform system routine operations of the optical disk drive. The invention not only helps to reduce production cost but also effectively detects whether a CD has been placed into the optical disk drive or not during the failure of a switch detector, thus avoiding Laser leakage that causes harm to users.

Abstract: A control apparatus and method for controlling a velocity of a spindle motor included in an optical disk reproducing system to prevent a forward or backward overrun of a spindle motor are disclosed. A widest signal detector of the apparatus detects the widest pulse width of an eight-to-fourteen modulation (EFM) signal according to a main clock signal and generates a first status signal representing a status of the pulse width of the detected signal according to a frame clock signal, which is divided by a first predetermined number j. A narrowest signal detector of the apparatus generates a second status signal representing a status of the narrowest pulse width of the first status signals according to the frame clock signal divided by a second predetermined number k, where k is greater than j. An overrun controller increases or decreases or holds a previously counted result according to the frame clock signal divided by the second predetermined number and the second status signal.

Abstract: An optical drive that detects a communication link interface speed to a host device and changes an optical media writing speed to reduce the likelihood that an error will occur during writing caused by an insufficient data interface rate in relation to the writing speed. In certain embodiments, the process for detecting and storing the preferred recording speed may be a software module which is part of the firmware of the optical drive. The invention provides a method of determining the preferred recording speed based on the interface speed and the maximum recording speed of the optical drive and storing this preferred recording speed for retrieval during recording of optical media.

Abstract: In an optical disc in/from which data is recorded or reproduced by irradiating a storage area on the optical disc with a laser, information containing recording velocity information (RVI) for recording/reproduction, which represents a linear velocity different from the standard linear velocity, and write strategy information (WSI) corresponding to the recording velocity information is stored in a land pre-pit or the like on the optical disc.

Abstract: There is disclosed an information storage apparatus with a low current consumption in a spindle motor or the like. A spindle motor driver 38 and spindle motor 40 serve as both a driver for driving a disk-like information storage medium in a predetermined direction and a brake for forcibly stopping rotation of the information storage medium, and by appropriately inputting, to the spindle motor driver 38, a spindle-on signal SPDLON for operating the spindle motor driver 38 and spindle motor 40 as the driver and a brake signal BRAKE for operation as the brake, MPU selectively uses a forced stop operation for stopping driving the information storage medium to forcibly stop the information storage medium, and a natural stop operation in which the spindle motor 40 simply stops driving the information storage medium.

Abstract: Optical disk device, in which a tracking adjustment system and sled adjustment system are controlled independently, has offset value acquisition capability, which detects the tracking drive signals output from tracking adjustment system for one lap around optical disk and acquires multiple tracking drive offset values. Such device also has offset representative value computation capability, which computes an offset representative value from multiple tracking drive offset values, as well as an offset value comparison capability, which compares the offset center value in the state in which no tracking adjustment control is done, and the offset representative value, as well as a sled drive decision means capability, which decides the drive of sled adjustment system 36 based on the comparison result.

Abstract: A method for controlling the rotational speed of a disk player includes first calculating the proportion of time which the disk player is reading data from the disk during a unit time T. Thereafter, the method increases the rotational speed of the disk player if the proportion of time that the disk player spends reading data from the disk is greater than a first threshold during each of m consecutive units of time T, and decreases the rotational speed of the disk player if the proportion of time that the disk player spends reading data from the disk is less than a second threshold during each of n consecutive units of time T.

Abstract: To provide a disk playback system that effectively uses the maximum playback speed and maximum search speed that the system owns. A disk playback system that searches for a desired position of a disk (2) on which information data is recorded at constant linear velocity after receiving a command from an external device, reads out desired information data, and outputs information data corresponding to the playback format of the disk. An outermost-perimeter-address memory circuit (21) renews stored address information to the newest address information, if the address information of the newest address accessed according to an access instruction of said disk indicates the newest address is outer perimeter than the outermost address that has been accessed, and determines a criterion for speed control of the disk (2), based on the renewed address information. A CAV control circuit (20) controls the speed of the disk 2, based on the determined criterion.

Abstract: An apparatus for recording and/or reproducing information on and/or from a magneto-optical disk including an optical head for projecting a laser beam onto a magneto-optical disk and receiving the laser beam reflected by the disk, an up-down block arranged movably between a lower position and an upper position, an up-down motor for moving said up-down block up and down, a turntable for supporting the disk and a spindle motor secured to said up-down block and having a driving shaft coupled with said turntable for rotating the turntable, a position detecting device for detecting a position of said up-down block to derive a position signal when the up-down block is driven into the upper position, a rotation detecting device for detecting a rotation of said optical information record disk to derive a rotation signal when the optical information record disk is rotated at a predetermined revolving speed, and a control device for initiating a focus control for moving said objective lens and turntable relative to each

Abstract: A disk drive apparatus drives, by means of a motor, a disk mounted thereon so as to reproduce signals recorded in the disk. The disk drive apparatus has an edge detecting unit for generating an edge signal XEG indicating a timing of phase switching, in accordance with a plurality of signals CU, CV and CW induced when the motor is driven. The disk drive apparatus further has a drive voltage controlling unit for controlling, in accordance with the edge detection signal XEG, the maximum value of a drive voltage VS for driving said motor. This arrangement implements optimal motor control, while reducing circuit scale and cost and, at the same time, enhancing adaptability of the disk drive apparatus.

Abstract: Given a CD-ROM drive having a plurality of speed ranges selectable in n-fold graduation and having linearly reduced rotational speeds within each speed range respectively between outer and inner sector and having the prescription that a reduction of the rotational speed automatically ensues given a negative read result, control means are provided that effective switching into a lower speed range when a predetermined noise level is upwardly transgressed and/or when vibrations occur.

Abstract: An optical disk recording method performs recording of data at a variable linear velocity multiplication factor in accordance with a radial position of a irradiation optical beam on an optical disk. The method is carried out by the steps of performing an actual recording with a variable writing power y=ax+b of the irradiation optical beam in accordance with a linear velocity multiplication factor x where the constant a is determined to a fixed value according to a type of the optical disk, performing a test recording before starting the actual recording such that the test recording is carried out with a test linear velocity multiplication factor to obtain an appropriate writing power of the irradiation optical beam, and setting the constant b by solving the function y=ax+b with using the results of the test recording, whereby the actual recording can be performed with an appropriate writing power y calculated based on the function y=ax+b having the set constants a and b.

Abstract: The speed of a CD drive that is coupled to a host can be adjusted by the steps of receiving a command from the host, calculating the processing speed required by the host for executing the received command, and adjusting the processing speed of the CD drive if the required processing speed of the host is either greater than or less than the current processing speed of the CD drive.

Abstract: A phase-change optical disc formatting device which formats a phase-change optical disc so that signal characteristics of an area in which at least one of a file structure and application data is to be recorded are substantially equal to signal characteristics of a format area. A phase-change optical disc formatting method including: formatting a phase-change optical disc so that signal characteristics of an area in which at least one of a file structure and application data is to be recorded are substantially equal to signal characteristics of a format area. A phase-change optical disc formatted such that signal characteristics of an area of the phase-change optical disc in which at least one of a file structure and application data is to be recorded are substantially equal to signal characteristics of a format area of the phasechange optical disc.