DISK APPARATUS

Abstract: When an optical disk (l2) is set in an disk apparatus (l0), the apparatus reads out identifina­ tion data recorded at a predetermined timing in a predetermined position of the optical disk (l2). The type of the optical disk (l2) is judged according to the identification data. That is, a judgement is made as to whether the optical disk (l2) is of a CAV type, in which the recording/reproduction timing, i.e., the demodulation/modulation frequency is constant irrespective of the access position on the disk, or whether it is of a M-CAV type, in which the recording/ reproduction timing, i.e., the demodulation/modulation frequency, is varied according to the access position. According to the result of judgement, the recording/ reproduction timing, with respect to the optical disk (l2), is controlled for recording or reproduction of data. The optical disk apparatus (l0) can be used both types of optical disk.

Description: This invention relates to a disk apparatus and, more particularly, a disk apparatus for reproducing data from a CAV type disk and M-CAV type disk and for recording data thereon. In a disk apparatus, for example, an optical disk apparatus, an optical disk is used for recording data on a spiral track. Recording or reproduction of data in or from the optical disk is performed by an optical head, which is moved linearly by a linear motor in the radial direction of the optical disk. The recording and reproduction of data in the optical disk apparatus are usually performed using a CAV (constant angular velocity) type disk or a CLV (constant linear velocity) type disk. In the CAV type disk, the angular velocity of the optical disk is held constant, to ensure steady recording or reproduction and to reduce access time. Further, in the CAV type disk, the recording or reproduction timing, i.e., the demodulation or modulation frequency, is constant. In the CLV type disk, on the other hand, the angular velocity of the optical disk for recording or reproduction is reduced as the optical head is moved toward the outer periphery of the optical disk, to obtain a constant linear velocity of the optical disk track with respect to the optical head. The CLV type disk is capable of high-density recording of data. However, since the angular velocity of the optical disk for recording and reproduction of data is varied with the movement of the optical head in the radial direction of the optical disk, it takes some time until the angular velocity of an optical disk drive motor is stabilized. In addition, the motor cannot be operated at high angular velocity. Therefore, this results in considerably long access time, and the data transfer rate is inevitably reduced. To obtain reduced access time, increased recording capacity, and increased data transfer rate, a modified constant angular velocity (M-CAV) system is used, in which the optical disk is rotated at a constant angular velocity while the recording or reproduction timing, i.e., the demodulation or modulation frequency, is varied according to the access position, thus achieving satisfactory recording or reproduction. Presently available optical disk apparatuses, however, are used with either CAV type optical disk or M-CAV type optical disk alone. Accordingly, demand has arisen for a disk apparatus which can be used with optical disks of both these systems. Prior art document JP-A-59 157873 discloses a retrieving device in which a reference voltage for control a speed is supplied to a speed control circuit from a microcomputer via a D/A converter. At the same time, the computer reads the code standard information recorded on a disk via a data demodulating circuit. Thus, it is judged whether the disk is equal to a CAV disk or a CLV disk. In the case of a CLV disk, the set value of the track crossing frequency is calculated again for correction in response to the CLV disk. Thus it is possible to retrieve at a high speed the position of a target track even for a disk having a fixed linear speed. In this way, it is possible to detect quickly the position of a target track by calculating again the set value of the crossing frequency of the target track and at the same time setting the reference voltage so that the number of revolutions of a disk is set previously equal to the number of revolutions at the position where the target address is reproduced. Further, prior art document US-A-4 357 635 describes a disk memory apparatus in which in a first operation method the rotational speed of a disk is progressively decreased in a linear manner as the radius of the track on which data is to be written or recorded increases. In a second operation method, the frequency of write clock pulses is progressively increased in a linear manner as the radius of the track increases. Finally, prior art document EP-A-0 054 438 discloses an optical disk in which information track portions are located in an annular area of the disk, and at least one pregrooved rotation index mark is indicative of a predetermined starting angle of the rotation of the disk. This index mark comprises a plurality of arcuate grooved portions located in an annular area, which is remote and kept clear from the annular area in which the information track portions are disposed. It is an object of the present invention to provide an improved disk apparatus and a method for operating the same which can be used with both CAV and M-CAV type disks. To solve this object the present invention provides a disk apparatus and a method as stated in anyone of claims 1, 9, 17, and 25. This invention can be more fully understood from the following detailed description when taken in conjunction with the accompanying drawings, in which: Figs. 1A and 1B are schematic representations of an optical disk apparatus according to an embodiment of the the present invention; Fig. 2 is a plan view showing an optical disk used with the optical disk apparatus shown in Fig. 1; Fig. 3 is a view showing a data table stored in a ROM shown in Fig. 1; Fig. 4 is a graph showing the relation between the radial position of optical disk track and the clock signal frequency; and Fig. 5 is a block diagram showing the detailed construction of a variable clock generator shown in Fig. l. Figs. lA and lB are schematic reproduction of an optical disk apparatus according to an embodiment of the present invention. The illustrated optical disk apparatus, which is generally designated by reference numeral l0, is used with optical disk l2 as a recording medium. Fig. 2 shows optical disk l2. This optical disk comprises a circular base made of glass or plastics and a doughnut-like metal coating of a metal such as tellurium or bismuth, formed on the circular base. Optical disk l2 has reference position mark l4, constituted by a notch, formed in the neighborhood of the center of the metal coating. The surface of optical disk l2 is divided into 256 sectors, 0 to 255, with reference position mark l4 as "0" reference. Optical disk l2 which is used with optical disk apparatus l0, is one of two different types, i.e., the CAV type in which the modulation and demodulation frequency is constant, and the M-CAV type in which the modulation and demodulation frequency is variable. With the CAV type optical disk, the recording density becomes progressively coarser toward the outer periphery of the disk. With the M-CAV type optical disk, on the other hand, the recording density is constant over the entire disk surface. The CAV or M-CAV type optical disk has identification data indicating that the frequency of modulation and demodulation is constant irrespective of the access position or variable according to the access position, the identification-data being recorded in a identification-data recording area which is found in the inner portion of the optical disk. The identification-data recording area is found at the same position on the CAV and M-CAV type optical disks. In other words, the modulation or demodulation frequency is same and is found at the same recording density position with the CAV and M-CAV type optical disks. As the identification data, a code "00" is recorded in the CAV type and code "0l" is recorded in the M-CAV type, for instance. In the M-CAV type optical disk, a recording/reproduciton unit is called a block and each data item to be recorded on or reproduced from every block has a fixed length. Please note that the number of sectors occupied by a block in the M-CAV type optical disk are arranged such that the block on the innermost side of the disk occupies 40 sectors while that on the outermost side occupies 20 sectors, for instance. With the CAV type optical disk, on the other hand, the number of sectors in each block is fixed, for example, 40. Block header l6, which consists of block number, track number, etc., is recorded at the start position of the block at the time of manufacture of optical disk l2, for instance. Further, if a block in the M-CAV type optical disk does not end at a sector-switching position, a block gap is provided, so that each block starts from a sector switching position. As is shown in Fig. l, optical disk l2 is driven by motor l8. Motor l8 is a spindle motor, the angular velocity of which is controlled to be constant (600 rpm), by motor-drive controller 20, to be described later. Optical head 22 is provided in close proximity to the underside of optical disk l2, for recording and reproducing data on and from the disk. Optical head 22 is mounted on DC linear-motor 24. DC linear-motor 24 consists of movable section 26 and stationary section 28. Optical head 22 is secured on movable section 20. DC linear-motor 24 is connected to linear-motor driver & servo circuit 30, so that movable section 26 is driven when DC linear-motor 24 is driven. When movable section 26 is driven, optical head 22 is moved linearly in the radial directions of optical disk l2, as is shown by arrows a and b. The position of movable section 26, i.e ., the position of optical head 22, is detected by position detector 32. The result of detection is supplied to linear-motor driver & servo circuit 30. Position detector 32 is based on a so-called overlap lattice type detection system, and provides two detection signals of different phases (the phase being different depending on the direction of movement) according to the extent of movement of movable section 26, i.e., the extent of movement of optical head 22. Optical head 22, which is secured to DC linear-motor 24, consists of a semiconductor laser, a collimator lens, a beam splitter, an objective lens, a focus drive coil for driving the objective lens toward optical disk l2, a tracking drive coil for driving the objective lens in the radial directions of optical disk l2, a focus detector including a pair of photo-detectors for checking whether a laser beam is focused on optical disk l2, and a tracking detector including a pair of photo-detectors for checking whether a data track of optical disk l2 is being tracked, these components being not shown. Each photo-detector provides a detection signal to a corresponding processing and/or driving circuit to be described later, and each processing and/or driving circuit supplies a predetermined voltage to each drive coil and semiconductor laser. Controller 34 controls optical disk apparatus l0 according to a control signal supplied from an external apparatus, i.e., the host computer (not shown), via interface 36. Linear-motor driver & servo circuit 30 drives DC linear-motor 24 according to a desired position signal supplied from controller 34 and also the output signal of detector 32. Motor-drive controller 20 judges the angular velocity according to a velocity clock from motor l8, and controls the velocity to a preset velocity, by means of controller 34. Focus servo circuit 38 controls the focal point of the objective lens in optical head 22 according to the detection signal from the focus detector in optical head 22. Focus pull-in circuit 40 permits focus servo circuit 38 to effect accurate focusing at the time of switching from a state in which the lens is out-of-focus, to a state in which the lens is in focus. Tracking servo circuit 42 moves the objective lens in the radial directions of optical disk l2 according to a detection signal from the tracking detector in optical head 22, such that the laser beam transmitted through the objective lens in optical head 22 is projected onto the center of the track. Trackjump pulse generator 44 generates a track-jump pulse according to a control signal from controller 34. When this track-jump pulse is supplied, tracking servo circuit 42 interrupts the servo operation and generates a track-jump drive pulse to move the objective lens such that the laser beam is displaced by one track. Bit-signal shaper 46 shapes the detection signal from the detector in optical head 22. Digitizer 48 digitizes the shaped signal output of bit-signal shaper 46. Reference-clock generator 50 generates a reference clock signal. Variable-clock generator 52 generates a clock signal (or reference signal) having a frequency (i.e., a duration) corresponding to clock rate data supplied from controller 34 according to the reference clock signal from reference-clock generator 50. In this case, the frequency of the clock signal generated from variable-clock generator 52 is increased (that is, the duration is reduced) as optical head 22 is moved toward the outer periphery of optical disk l2. In accordance with a control signal from controller 34, reproduction-sync clock extractor 54 extracts a reproduction-sync clock from data supplied from digitizer 48 whenever the data falls within the frequency range of the clock signal supplied from variable-clock generator 52. Demodulator 56 MFM demodulates data supplied from digitizer 48, using the reproduction-sync clock from reproduction-sync clock extractor 54. Serial/parallel converter 58 effects serial-to-parallel conversion of the reproduced signal output of demodulator 56, under the control of the clock signal supplied from variable-clock generator 52. Header discriminator 60 discriminates header data from the reproduced signal output of demodulator 56. Recording/reproduction header register 62 stores header data which is to be accessed, and is supplied from controller 34. Header comparator 64 checks whether header data stored in recoding/reproduction header register 62 and header data supplied from header discriminator 60 coincide. When the two header data compared coincide, it produces a coincidence signal. Parallel/serial converter 66 effects parallel/serial conversion of the recording data supplied from recording/reproduction switching circuit 68, to be described later, under the control of the clock signal from variable-clock generator 52. Modulator 70 MFM modulates data supplied from parallel/serial converter 66 under control of the clock signal from variable-clock generator 52. Laser driver 72 drives the semiconductor laser in optical head 22 according to the modulation output of modulator 70, to record data on optical disk l2. When header comparator 64 provides the coincidence signal, recording/reproduction switching circuit 68 supplies reproduction data, subsequent to header data supplied from serial/parallel converter 58, to recording/reproduction data buffer 74, according to a reproduction control signal supplied from controller 34. Further, when header comparator 64 provides the coincidence signal, circuit 68 supplies recording data supplied from recording/reproduction data buffer 74, to parallel/serial converter 66, according to a recording control signal supplied form controller 34. Recording/reproduction data buffer 74 stores reproduction data from recording/reproduction switching circuit 68 and also stores recording data from recording/reproduction data-transfer circuit 76, to be described later. Error-correction code addition & error-correction circuit 78 adds error-correction code to recording data stored in recording/reproduction data buffer 74 and effects error-correction of reproduction data stored in recording/reproduction data buffer 74. Recording/reproduction data-transfer circuit 76 transfers reproduction data supplied from recording/reproduction data buffer 74 to the host computer, via interface 36, and also transfers recording data supplied from the host computer, via interface 36, to recording/reproduction data buffer 74. In order to check the disk mode at the time of starting, reproduction data (identification data) in recording/reproduction data buffer 74 is supplied not to recording/reproduction data-transfer circuit 76, but to controller 34. In ROM 80, which serves as memory circuit, a conversion table as shown in Fig. 3 is stored, in which clock rate data of optical disk l2, the number of sectors in one block at the clock rate, the first block number at the clock rate, and the start sector number in the block are listed for each of the 256 tracks. To judge the disk mode at the time of the start, controller 34 effects a judgement according to reproduction data (identification data) supplied from recording/reproduction data buffer 74, as to whether the optical disk set in apparatus l0 is CAV or M-CAV type optical data. For example, when code "00" is supplied as identification data from recording/reproduction data buffer 74, controller 34 judges that a CAV type optical disk has been set. When code "0l" is supplied as identification data, it is judged that a M-CAV type optical disk has been set. According to the result of the judgement, controller 34 selects either a first mode, in which the clock signal provided from variable clock generator 52 is constant, irrespective of the accessed position, or a second mode, in which the clock signal is varied according to the accessed position. The first mode is selected in the case of the CAV type disk, and the second mode in the case of the M-CAV type. When the first mode is selected, controller 34 controls variable-clock generator 52 such that generator 52 generates a clock signal having a constant frequency irrespective of the accessed position on optical disk l2, as shown by dashed line A in Fig. 4. When the second mode is selected, controller 34 controls variable-clock generator 52 such that generator 52 generates a clock signal, the frequency of which is varied according to the accessed position on optical disk l2, as shown by solid line B. In the second mode, the clock signal frequency is the same for blocks having the same number of sectors. The frequency thus is varied like a staircase. The discrimination data noted above is stored in recording area C, in which the clock signal frequency is the same in the first and second modes as shown. In the first mode, when the block number corresponding to the position of recording or reproduction, i.e., the access position, is provided from the host computer via interface 36, controller 34 reads out the access position from ROM 80, and causes accessing by DC linear-motor 24 and optical head 22, with the clock signal frequency held constant. In the second mode, controller 34 reads out clock-rate data and the access position corresponding to the block number, from ROM 80, and causes accessing by DC linear-motor 24 and optical head 22 in a state in which a clock signal corresponding to the clock rate is being provided. The reading (computation) of the clock-rate data and the access position is described in detail in EP-A-0 158 067 of T. Yoshimaru entitled "Optical Disk Device" filed on February 22, l985 and assigned to KABUSHIKI KAISHA TOSHIBA; therefore, a detailed description is not given herein. Variable-clock generator 52 has a construction as shown in Fig. 5. It includes frequency divider 82 and PLL circuit 84. PLL circuit 84 consists of phase comparator 86, phase/voltage converter 88, voltage-controlled oscillator (vco) 90, and frequency divider 92. The frequency of the output of PLL circuit 84, i.e., the clock signal, is controlled through control of the frequency of frequency divider 92 of PLL circuit 84, by controller 34. The operation of optical disk apparatus l0 having the above construction will now be described. When optical disk l2 is set in optical disk apparatus l0, controller 34 supplies a control signal to motor-drive controller 20, to drive motor l8, so as to drive optical disk l2 at a predetermined speed. Controller 34 then reads out, from ROM 80, clock-rate data and the access position, i.e., the track number and first sector number, for the block number corresponding to an identifier recording block provided in area C, where the identification data is recorded. Controller 34 supplies the read-out clock-rate data to variable-clock generator 52. Variable-clock generator 52 generates a clock signal at a frequency (i.e., duration) corresponding to clock-rate data supplied from controller 34, using the reference clock signal from reference-clock generator 50, and supplies the generated clock signal to reproduction-sync clock extractor 54, demodulator 56, serial/parallel converter 58, header discriminator 60, parallel/serial converter 66, and modulator 70. Controller 34 also converts the track number, read out from ROM 80, into a scale value and supplies this value to linear-motor driver & servo circuit 30. Linear-motor driver & servo circuit 30 drives DC linear-motor 22 to drive optical head 22 until there occurs a coincidence of the scale value and the position represented by the output of position detector 32. When the movement of optical head 22 is then stopped, the detection signal from the detector in optical head 22 is shaped in shaper 46 and is then binalized in digitizer 48 to be supplied to reproduction-sync clock extractor 54 and demodulator 56. Reproduction-sync clock extractor 54 extracts a reproduction-sync clock from the supplied data and supplies the extracted clock to demodulator 56. Demodulator 56 MFM demodulates the read-out data supplied from digitizer 48, using the reproduction-sync clock supplied from reproduction-sync clock extractor 54. The demodulated output is supplied via serial/parallel converter 58 to recording/reproduction switching circuit 68 and is also supplied to header discriminator 60. Header discriminator 60 discriminates only header data from the supplied demodulation output, and supplies the header data to controller 34. Controller 34 judges, from the header data, the track in correspondence to optical head 22 and compares this track and the desired track. When it judges that the two compared tracks are spaced apart by several tens of tracks or more, controller 34 causes DC linear-motor 24 to move optical head 22 again. When it judges that the two compared tracks are spaced apart by less than several tens of tracks, controller 34 supplies a control signal to track-jump pulse generator 44, to cause displacement of optical head 22 by a corresponding number of tracks. When optical disk 22 is brought to the position corresponding to the desired track, header discriminator 60 discriminates only header data and supplies this data to header comparator 64. At this time, header data in the desired block, i.e., the identifier recording block provided in recording area C, has been preliminarily stored in recording/reproduction header register 62, by controller 34, and the header data in recording/reproduction header register 62 is supplied to header comparator 64. Header comparator 64 compares the two header data and if the two data coincide, it provides the coincidence signal to recording/reproduction switching circuit 68. In response to this coincidence signal, recording/reproduction switching circuit 68 supplies reproduction data, supplied subsequent to the header data, from serial/parallel converter 58 to recording/reproduction data buffer 74. The reproduction data in recording/reproduction data buffer 74 is supplied to error-correction code-addition & error-correction circuit 78 for error-correction before being supplied to controller 34. When the supplied reproduction data (i.e., identification data) is "00", controller 34 judges that a CAV type optical disk has been set, and selects the first mode. Thus, variable-clock generator 52 is controlled such that it provides a clock signal having a constant frequency, irrespective of the accessed position on optical disk l2, as is shown by dashed line A in Fig. 4. When the reproduction data from recording/reproduction data buffer 74 is "0l", controller 34 judges that a M-CAV type optical disk has been set, and selects the second mode. Variable-clock generator 52 is thus controlled, such that it provides a clock signal, the frequency of which is varied according to the accessed position on optical disk l2, as is shown by solid line B in Fig. 4. Now, the recording of data in the case when the first mode is selected, will be described. It is assumed that a block number for recording data (i.e., for being accessed) is supplied from the host computer, via interface 30, to controller 34. In this case, controller 34 computes the track and start sector of the desired block, using the conversion table stored in ROM 80. Since the first mode is selected, controller 34 causes variable-clock generator 52 to provide a clock signal at a constant frequency, irrespective of the access position. The constant-frequency clock signal is supplied to reproduction-sync clock extractor 54, demodulator 56, serial/parallel converter 58, header discriminator 60, parallel/serial converter 66, and modulator 70. Further, based on the track number noted above, controller 34 causes the laser beam from optical head 22 to be incident upon the track on which a desired block is located, which operation is the same as that of accessing the identifer recording block provided in recording area C. At this time, recording data from the host computer has been stored in recording/reproduction data buffer 74, via interface 30 and recording/reproduction data-transfer circuit 76. Further, the recording data is supplied to error-correction code-addition & error-correction circuit 78 for error-correction code addition. When comparator 64 supplies the coincidence signal, with respect to the header data of the desired block, to recording/reproduction switching circuit 68, the recording data of recording/reproduction data buffer 74 is supplied via recording/reproduction switching circuit 68 to parallel/serial converter 66. The serial recording data output of parallel/serial converter 66 is MFM modulated in modulator 70, to be supplied to laser driver 72. Laser driver 72 drives the semiconductor laser in optical head 22 according to the supplied modulation signal, thus causing the recording of data. Data of other blocks is also recorded in the manner described above. In this case, data is recorded under control of the constant-frequency clock signal, even when the block position is changed. Now, reproduction of data will be described. It is assumed that a block number for reproduction (i.e., for accessing) is supplied from the host computer, via interface 36, to controller 34. Then, the laser beam of optical head 22 is caused to be incident upon the track on which a desired block is located, which operation is performed in the manner as described before, in conjunction with the recording. When header comparator 64 supplies the coincidence signal, with respect to the header data of the desired block, to recording/reproduction switching circuit 68, the reproduction data from serial/parallel converter 58 is supplied via recording/reproduction switching circuit 68 to recording/reproduction data buffer 74. The reproduction data stored in recording/reproduction data buffer 74 is supplied to error-correction code-addition & error-correction circuit 78 for error correction, before being transferred, via recording/reproduction data-transfer circuit 76 and interface 36, to the host computer. Data in other blocks is reproduced in the manner described above. In this case, data is reproduced under control of the constant-frequency clock signal, even when the block position is changed. Now, recording of data, when the second mode is selected, will be described. It is assumed that a block number for recording (i.e., for accessing) is supplied from the host computer, via interface 38, to controller 34. Then, controller 34 computes the desired block track, start sector, and clock-rate data, using the conversion table in ROM 80. Controller 34 provides clock-rate data to variable-clock generator 52. Variable-clock generator 52 generates a clock signal at a frequency corresponding to the clock-rate data supplied from controller 34, using the reference clock signal from reference clock generator 50. This clock signal is supplied to reproduction-sync clock extractor 54, demodulator 56, serial/parallel converter 58, header discriminator 60, parallel/serial converter 66, and modulator 70. Further, according to the track number noted above, controller 34 causes the laser beam of optical head 22 to be incident upon the track on which a desired block is located, which operation is performed in the manner as described before in connection with the accessing of the identifier recording block provided in recording area C. At this time, recording data from the host computer has been stored in recording/reproduction data buffer 74, via interface 36 and recording/reproduction data-transfer circuit 76. In addition, the recording data is supplied to error-correction code-addition & error-correction circuit 78 for error-correction code addition. When comparator 64 supplies the coincidence signal, with respect to the desired block track, to recording/reproduction switching circuit 68, the recording data in recording/reproduction data buffer 74 is supplied via recording/reproduction switching circuit 68 to parallel/serial converter 66. The serial recording data output of parallel/serial converter 66 is MFM modulated in modulator 70, to be supplied to laser driver 72. Laser driver 72 drives the semiconductor laser in optical head l2 according to the supplied modulation signal, thus effecting data-recording. Data in other blocks are recorded in the manner described above. In this case, data is recorded, under control of a clock signal, at a frequency which is increased with change in the block position toward the outer periphery of the disk. Now, reproduction of data will be described. It is assumed that a block number for recording (i.e., for accessing) is supplied from the host computer, via interface 30, to controller 34. Then, as in the recording mode, controller 34 reads out clock-rate data for that block and causes variable-clock generator 52 to generate a clock signal at a frequency corresponding to the clock-rate data. This clock signal is supplied to reproduction-sync clock extractor 54, demodulator 56, serial/parallel converter 58, header discriminator 60, parallel/serial converter 66, and modulator 70. Further, as in the recording mode, the laser beam of optical head 22 is incident upon the track on which a desired block exists. When header comparator 64 provides the coincidence signal, with respect to the header data of the desired block, to recording/reproduction switching circuit 68, the reproduction data from serial/parallel converter 58 is supplied via recording/reproduction switching circuit 68 to recording/reproduction data buffer 74. The reproduction data stored in recording/reproduction data buffer 74 is supplied to error-correction code-addition & error-correction circuit 78 for error correction, before being transferred, via recording/ eproduction data-transfer circuit 76 and interface 36, to the host computer. Data in other blocks is reproduced in the manner described above. In this case, data is reproduced under control of a clock signal having a frequency which is increased with change in the block position toward the outer periphery of the disk. As has been described in the foregoing, with optical disk apparatus 10 according to the present invention, a clock signal at a predetermined frequency is supplied to modulator means and demodulator means at the time of starting (initial setting) when optical disk 12 is set, and discrimination data indicative of whether the clock signal frequency is constant or variable is read out from a predetermined position, i.e., the identifier recording block provided in recording area C of the optical disk, whereby recording or reproduction is performed under control of a clock signal, the frequency of which is either constant or variable according to the access position of optical disk 12, according to the read-out identification data. Thus, it is possible to accomodate both CAV and M-CAV type optical disks.

Claims: A disk apparatus for reproducing data from both first and second type disk, said first disk being of a type for recording data at a constant frequency irrespective of an access position, said second type disk being of a type for recording data at a frequency modified in accordance with an access position, said first and second type disks having an identification data for identifying the type of the disk, and said identification data being initially recorded with a predetermined frequency equal to said constant frequency and at a predetermined position (C) selected such that said modified frequency at said position is equal to said constant frequency, comprising: means for selectively loading one of the first and second type disks; identifying means for identifying a type of a disk loaded on said loading means according to the identification data recorded at said predetermined position (C); and means for reproducing data recorded on the loaded disk; wherein said identifying means includes: means for rotating the loaded disk at a predetermined rotation speed common to said first and second disks; identification data reproducing means for reproducing said identification data recorded at said predetermined position (C) from the rotated disk at said predetermined frequency; and judging means (34) for receiving said identification data reproduced by said identification data reproducing means, judging said identification data to see whether the loaded disk belongs to the first type disk or the second type disk, and outputting a judgment result data; and said data reproducing means receptive to said judgment result data frog said judging means (34) and external access position information, reproduces when said judgment result data identifies the first type of disk, data recorded at the disk position designated by said access position information at said constant frequency irrespective of the access position, and reproduces when said judgment result data identifies the second type of disk, data recorded on the disk position designated by said access position information at a frequency modified in accordance with the access position of said second type of disk. The disk apparatus according to claim 1, characterized in that said modified frequency is gradually increased stepwise, from the inside of said second type of disk to the outside thereof. The disk apparatus according to claim 2, characterized in that from the inside toward the outside of the second type disk said modified frequency is gradually and stepwise increased in accordance with said access position. The disk apparatus according to claim 3, characterized in that said data reproducing means comprises a head (22) for reading out data recorded on the loaded disk, a demodulator (56) for demodulating the data read from said head (22), modifying means for modifying a demodulating frequency of said demodulator (56) and control means (34) for controlling said modifying means: wherein, when the judgement result data supplied from said judging means (34) identifies the first type of disk, said control means (34) controls said modifying means, to cause the demodulating frequency of said demodulator (56) to be modified to said constant frequency, and when said judgement result data identifies the second type of disk, said control means (34) controls said modifying means, to cause the demodulating frequency of said demodulator (56) to be equal to the frequency modified in accordance with said designated access position. The disk apparatus according to claim 4, characterized in that said control means (34) supplies demodulation frequency data to said modifying means in accordance with the judgement result data from said judging means (34), said modifying means generates a demodulation timing signal of said predetermined or modified frequency on the basis of the demodulation frequency data, and said demodulator (56) demodulates data supplied from said head (22) by the demodulated timing pulse signal. The disk apparatus according to claim 5, characterized in that said modifying means comprises a variable clock generator (52) including a PLL circuit (84) comprising a loop of a phase comparator (86), a phase/voltage converter (88), a voltage-controlled ocillator (90) and frequency divider (92), and a reference clock generator (50) for supplying a reference clock to another input of said phase comparator (86), wherein a frequency of said demodulation timing pulse signal, which is an output of the voltage-controlled ocillator (90) in the PLL circuit (84), is controlled by controlling the output frequency of said frequency divider (92), on the basis of the demodulation frequency data supplied from said control means (34). The disk apparatus according to claim 5, characterized in that said control means (34) includes memory means (80) for storing a plurality of demodulation frequency data corresponding to an equal number of access positions for the second type of disk, wherein, when judgement result data from said judging means (34) identifies said second type of disk, demodulation frequency data corresponding to the external access position information is read out of said memory means (80) and is supplied to said modifying means. The disk apparatus according to claim 7, characterized in that said second type of disc has a predetermined number of continuous blocks, said memory means (80) stores demodulation frequency data with respect to a plurality of block groups, including a predetermined number of blocks, and said access position corresponds to said block groups. A disk apparatus for recording data to both first and second type disk, said first disk being of a type for recording data at a constant frequency irrespective of an access position, said second type disk being of a type for recording data at a frequency modified in accordance with an access position, said first and second type disks having an identification data for identifying the type of the disk, and said identification data being initially recorded with a predetermined frequency equal to said constant frequency and at a predetermined position (C) selected such that said modified frequency at said position is equal to said constant frequency, comprising: means for selectively loading one of the first and second type disks; identifying means for identifying a type of a disk loaded on said loading means according to the identification data recorded at said predetermined position (C); and means for recording data to the loaded disk; wherein said identifying means includes: means for rotating the loaded disk at a predetermined rotation speed common to said first and second disks; identification data reproducing means for reproducing said identification data recorded at said predetermined position (C) from the rotated disk at said predetermined frequency; and judging means (34) for receiving said identification data reproduced by said identification data reproducing means, judging said identification data to see whether the loaded disk belongs to the first type disk or the second type disk, and outputting a judgement result data; and said data recording means receptive to said judgement result data from said judging means (34) and external access position information, records when said judgment result data identifies the first type of disk, data to the disk position designated by said access position information at said constant frequency irrespective of the access position, and records when said judgement result data identifies the second type of disk, data to the disk position designated by said access position information at a frequency modified in accordance the access position of said second type of disk. The disk apparatus according to claim 9, characterized in that said modified frequency is gradually increased stepwise, from the inside of said second type of disk to the outside thereof. The disk apparatus according to claim 10, characterized in that from the inside toward the outside of the second type disk said modified frequency is gradually and stepwise increased in accordance with said access position. The disk apparatus according to claim 11, characterized in that said recording means comprises a head (22) for recording data to the loaded disk, a modulator (70) for modulating the data supplied to said head (22), modifying means for modifying a modulating frequency of said modulator (70) and control means (34) for controlling said modifying means, wherein, when the judgement result data supplied from said judging means (34) identifies the first type of disk, said control means (34) controls said modifying means, to cause the modulating frequency of said modulator (70) to be modified to said constant frequency, and when said judgement result data identifies the second type of disks said control means (34) controls said modifying means, to cause the modulating frequency of said modulator (70) to be equal to the frequency modified in accordance with said designated access position. The disk apparatus according to claim 12, characterized in that said control means (34) supplies modulation frequency data to said modifying means in accordance with the judgement result data from said judging means (34), said modifying means generates a modulation timing signal of said predetermined or modified frequency on the basis of the modulation frequency data, and said modulator (70) modulates data supplied from said head (22) by the modulated timing pulse signal. The disk apparatus according to claim 13, characterized in that said modifying means comprises a variable clock generator (52) including a PLL circuit (84) comprising a loop of a phase comparator (86), a phase/voltage converter (88), a voltage-controlled ocillator (90) and a frequency divider (92), and a reference clock generator (50) for supplying a reference clock to another input of said phase comparator (86), wherein a frequency of said modulation timing pulse signal, which is an output of the voltage-controlled ocillator (90) in the PLL circuit (84), is controlled by controlling the output frequency of said frequency divider (92), on the basis of the modulation frequency data supplied from said control means (34). The disk apparatus according to claim 13, characterized in that said control means (34) includes memory means (80) for storing a plurality of modulation frequency data corresponding to an equal number of access positions for the second type of disk, wherein when judgement result data from said judging means (34) identifies said second type of disk, modulation frequency data corresponding to the external access position information is read out of said memory means (80) and is supplied to said modifying means. The disk apparatus according to claim 15, characterized in that said discs have a predetermined number or continuous blocks, said memory means (80) stores modulation frequency data with respect to a plurality of block groups, including a predetermined number of blocks, and said access position corresponds to said block groups. A method for reproducing data from both first and second type disk, said first disk being of a type for recording data at a constant frequency irrespective of an access position, said second type disk being of a type for recording data at a frequency modified in accordance with an access position, said first and second type disks having an identification data for identifying the type of the disk, and said identification data being initially recorded with a predetermined frequency equal to said constant frequency and at a predetermined position (C) selected such that said modified frequency at said position is equal to said constant frequency, said method comprising: a step of selectively loading one of the first and second type disks; a step of identifying a type of a disk loaded on said loading means according to the identification data recorded at said predetermined position (C); and a step of reproducing data recorded on the loaded disk; wherein said identifying step includes: a step of rotating the loaded disk at a predetermined rotation speed common to said first and second disks; a step of reproducing said identification data recorded at said predetermined position (C) from the rotated disk at said predetermined frequency; and a step of receiving said identification data reproduced by said identification data reproducing means, judging said identification data to see whether the loaded disk belongs to the first type disk or the second type disk, and outputting a judgment result data; and said data reproducing step includes: a step of receiving said judgment result data from said judging means (34) and external access position information, a step of reproducing when said judgment result data identifies the first type of disk, data recorded at the disk position designated by said access position information at said constant frequency irrespective of the access position, and a step of reproducing when said judgment result data identifies the second type of disk, data recorded on the disk position designated by said access position information at a frequency modified in accordance the access position of said second type of disk. The method according to claim 17, characterized in that said modified frequency is gradually increased stepwise, from the inside of said second type of disk to the outside thereof. The method according to claim 18, characterized in that from the inside toward the outside of the second type disk said modified frequency is gradually and stepwise increased in accordance with said access position. The method according to claim 19, characterized in that said data reproduction is performed by reproducing means comprising a head (22) for reading out data recorded on the loaded disk, a demodulator (56) for demodulating the data read from said head (22), modifying means for modifying a demodulating frequency of said demodulator (56) and control means (34) for controlling said modifying means, wherein, when the loaded disk identifies the first type of disk, said control means (34) controls said modifying means, to cause the demodulating frequency of said demodulator (56) to be modified to said constant frequency, and when the loaded disk identifies the second type of disk, said control means (34) controls said modifying means, to cause the demodulating frequency of said demodulator (56) to be equal to the frequency modified in accordance with said designated access position. The method according to claim 20, characterized in that said control means (34) supplies demodulation frequency data corresponding to the type of the loaded disk to said modifying means in accordance with the judgement result data from said judging means (34), said modifying means generates a demodulation timing signal of said predetermined or modified frequency on the basis of the demodulation frequency data, and said demodulator (56) demodulates data supplied from said head (22) by the demodulated timing pulse signal. The method according to claim 21, characterized in that said modifying means comprises a variable clock generator (52) including a PLL circuit (84) comprising a loop of a phase comparator (86), a phase/voltage converter (88), a voltage-controlled ocillator (90) and a frequency divider (92), and a reference clock generator (50) for supplying a reference clock to another of said phase comparator (86), wherein a frequency of said demodulation timing pulse signal, which is an output of the voltage-controlled ocillator (88) in the PLL circuit (64), is controlled by controlling the output frequency of said frequency divider (92), on the basis of the demodulation frequency data supplied from said control means (34). The method according to claim 21, characterized in that said control means (34) includes memory means (80) for storing a plurality of demodulation frequency data corresponding to an equal number of access positions for the second type of disk, wherein when the loaded disk identifies said second type of disk, demodulation frequency data corresponding to the external access position information is read out of said memory means (80) and is supplied to said modifying means. The method according to claim 23, characterized in that said disks have a predetermined number of continuous blocks, said memory means (80) stores demodulation frequency data with respect to a plurality of block groups, including a predetermined number of blocks, and said access position corresponds to said block groups. A method for recording data to both first and second type disk, said first disk being of a type for recording data at a constant frequency irrespective of an access position, said second type disk being of a type for recording data at a frequency modified in accordance with an access position, said first and second type disks having an identification data for identifying the type of the disk, and said identification data being initially recorded with a predetermined frequency equal to said constant frequency and at a predetermined position (C) selected such that said modified frequency at said position is equal to said constant frequency, said method comprising: a step of selectively loading one of the first and second type disks; a step of identifying a type of a disk loaded on said loading means according to the identification data recorded at said predetermined position (C); and a step of recording data to the loaded disk; wherein said identifying step includes: a step of rotating the loaded disk at a predetermined rotation speed common to said first and second disks; a step of reproducing said identification data recorded at said predetermined position (C) from the rotated disk at said predetermined frequency; and a step of receiving said identification data reproduced by said identification data reproducing means, judging said identification data to see whether the loaded disk belongs to the first type disk or the second type disk, and outputting a judgment result data; and said data recording step includes: a step of receiving said judgment result data from said judging means (34) and external access position information, a step of recording when said judgment result data identifies the first type of disk, data to the disk position designated by said access position information at said constant frequency irrespective of the access position, and a step of recording when said judgment result data identifies the second type of disk, data to the disk position designated by said access position information at a frequency modified in accordance the access position of said second type of disk. The method according to claim 25, characterized in that said modified frequency is gradually increased stepwise, from the inside of said second type of disk to the outside thereof. The method according to claim 26, characterized in that from the inside toward the outside of the second type disk said modified frequency is gradually and stepwise increased in accordance with said access position. The method according to claim 27, characterized in that said data recording is performed by a recording means comprising a head (22) for recording data to the loaded disk, a modulator (70) for modulating the data supplied to said head (22), modifying means for modifying a modulating frequency of said modulator (70) and control means (34) for controlling said modifying means, wherein, when the loaded disk identifies the first type of disk, said control means (34) controls said modifying means, to cause the modulating frequency of said modulator (70) to be modified to said constant frequency, and when the loaded disk identifies the second type of disk, said control means (34) controls said modifying means, to cause the modulating frequency or said modulator (70) to be equal to the frequency modified in accordance with said designated access position. The method according to claim 28, characterized in that said control means (34) supplies modulation frequency data corresponding to the type of the loaded disk to said modifying means in accordance with the judgement result data from said judging means (34), said modifying means generates a modulation timing signal of said predetermined or modified frequency on the basis of the modulation frequency data, and said modulator (70) modulates data supplied to said head (22) by the modulated timing pulse signal. The method according to claim 29, characterized in that said modifying means comprises a variable clock generator (52) including a PLL circuit (84) comprising a loop of a phase comparator (86), a phase/voltage converter (88), a voltage-controlled ocillator (90) and a frequency divider (92), and a reference clock generator (50) for supplying a reference clock to another of said phase comparator (86), wherein a frequency of said demodulation timing pulse signal, which is an output of the voltage-controlled ocillator (88) in the PLL circuit (64), is controlled by controlling the output frequency of said frequency divider (92), on the basis of the modulation frequency data supplied from said control means (34). The method according to claim 29, characterized in that said control means (34) includes memory means (80) for storing a plurality of modulation frequency data corresponding to an equal number of access positions for the second type of disk, wherein, when the loaded disk identifies said second type of disk, modulation frequency data corresponding to the external access position information is read out of said memory means (80) and is supplied to said modifying means. The method according to claim 31, characterized in that said disks have a predetermined number of continuous blocks, said memory means (80) stores modulation frequency data with respect to a plurality of block groups, including a predetermined number of blocks, and said access position corresponds to said block groups.

Inventors: ISHIHARA, ATSUSHI C/O PATENT DIVISION K.K. TOSHIBA
Applicants: KABUSHIKI KAISHA TOSHIBA
Application year: 1986
Main classification: G11B7
IPC codes: G11B20, G11B7, G11B19