JP2005209307A - Disk reproducing method, disk reproducing apparatus, disk reproducing system, and program for responding to access request - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase access performing speed in the case of multi-access and to extend a lifetime of a reading head and a mechanical deck part. <P>SOLUTION: A disk reproducing apparatus 10 is provided with eight optical heads 3a-3h. A system controller 50 selects an optical head responding to access request in order of rotation or randomly conforming to standard in which a working time or the number of times of working of the optical heads 3a-3h are averaged out of optical heads being not worked in the optical heads 3a-3h when access request for an optical disk 1 is performed from any of channels, and makes the optical head read data instructed by the access request. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method and apparatus for reading data from a disk medium by accessing a disk medium on which data such as music data and video data is recorded, a computer program for access request response used in the disk reproduction method, and its The present invention relates to a disk playback system including a disk playback device.

  Random access and multi-access are possible for optical discs such as CD (Compact Disc) and DVD (Digital Versatile Disc), magneto-optical discs such as Mini-Disc (registered trademark), and disc media such as magnetic discs.

  In Patent Document 1 (Japanese Patent Laid-Open No. 10-293990), multi-access is recorded and reproduced simultaneously on different areas of a disk medium. It is shown that the process of reading data is performed simultaneously.

  Patent Document 2 (Japanese Patent Laid-Open No. 2000-278647) corresponds to a requested playback speed when there is an image playback request in a multi-channel AV (Audio and Visual) server having a plurality of hard disks. It is shown that if a change in playback speed is requested by reading out part of the image data, storing it in the buffer memory, reading it from the buffer memory and composing the playback image, it will respond immediately to the request Yes.

  However, this is not the multi-access that performs recording and playback at the same time or multi-channel using multiple hard disks, but multiple users can simultaneously access a single disk medium containing a large number of songs and video titles. Therefore, it is possible to play and listen to the songs and video titles that you want.

  Specifically, in this case, when the users U1, U2, U3 try to listen to the songs M1, M2, M3, respectively, and access one optical disk at the same time, the disk reproducing apparatus firstly performs the operation as shown in FIG. Then, the optical head 2 is moved to the head position of the music piece M1 on the optical disc 1, and the data of the first part M1a of the music piece M1 is read and written to the buffer memory 451 of the channel.

  Next, as indicated by the arrow S12, the optical head 2 is moved to the head position of the music piece M2, the data of the first portion M2a of the music piece M2 is read and written to the buffer memory 452 of the channel, and then the arrow S23. As shown, the optical head 2 is moved to the head position of the music M3, and the data of the first part M3a of the music M3 is read and written to the buffer memory 453 of the channel. Next, returning to the tune M1, the optical head 2 is moved to the next portion M1b of the tune M1, and the data of the portion M1b is read and written into the buffer memory 451. The same applies thereafter.

  As shown in FIG. 10 ("ch" in the figure is a channel and "seek" is the movement of the optical head 2 in the disk radial direction), the data stored in the buffer memories 451, 452, and 453 are respectively buffered. Data are read from the buffer memories 451, 452, 453 at a rate lower than the transfer rate to the memories 451, 452, 453, and decoded by the decoders 461, 462, 463. Thus, the music pieces M1, M2, and M3 can be continuously reproduced as the outputs PB1, PB2, and PB3 of the respective channels.

The prior art documents listed above are as follows.
JP-A-10-293990 JP 2000-278647 A

  However, in multi-channel playback by multi-access as described above, it takes time until access is executed and playback output is obtained at the start of access.

  Specifically, in the examples of FIGS. 9 and 10, when the access commands by the access operations of the users U1, U2, and U3 are accepted almost simultaneously at the time points t1, t2, and t3, the reproduction output of the last song M3 is performed. Until the time PB3 is obtained, from time t3, the time for the optical head 2 to move to the beginning position of the song M1, the time to read the data of the first part M1a of the song M1, the time to move from there to the beginning position of the song M2, It takes time to read the data of the first part M2a of the music M2, the time to move to the head position of the music M3, and the time to read the data of the first part M3a of the music M3. If the number of access channels is larger, it takes longer time.

  In addition, since the optical head 2 is frequently sought and the time for operating the optical head 2 is increased, the burden on the optical head 2 and the mechanical deck is increased, and the life of the optical head 2 and the mechanical deck is shortened.

  Therefore, the present invention is capable of speeding up the access execution in the case of multi-access and extending the life of the read head and the mechanical deck unit.

The disc playback method of the present invention comprises:
A method of reading data from a disk medium with a disk playback device comprising a plurality of read heads that can be operated independently of each other and movable in the radial direction of each loaded disk medium,
When access to the disk medium is requested, out of non-operating read heads in the plurality of read heads according to a criterion for averaging the operating time or number of operations of the plurality of read heads, or cyclically A head selection step of selecting a read head that responds to the access request in order or randomly;
Allowing the selected read head to access the disk medium and causing the selected read head to read data; and
Is provided.

  In the disk reproduction method of the present invention of the above method, a read head that responds to the access request is selected from a plurality of read heads for each access request, and one read head responds only to an access request for one channel. Even in the case of multi-access, the access execution becomes faster.

  In addition, since the read heads that respond to the access request are selected according to a standard that averages the operation time or the number of operations of a plurality of read heads, or in a cyclic order or at random, as a result, The operating time or the number of operations of the read heads are averaged, and it is prevented that only some of the read heads are operated for a long time or many times, thereby shortening the life of some of the read heads and mechanical deck parts. The life of the read head and mechanical deck is extended.

  As described above, according to the present invention, it is possible to speed up the access execution in the case of multi-access, and to extend the life of the read head and the mechanical deck unit.

[First Embodiment of Disc Playback Device and Disc Playback Method: FIGS. 1 to 6]
(Configuration of disc playback apparatus and disc playback system: FIGS. 1 and 2)
FIG. 1 shows an example of a disk reproducing apparatus according to the present invention, which is capable of multi-channel reproduction by multi-access for reproducing data recorded on an optical disk 1 such as a CD or DVD.

  The optical disk 1 is recorded with a lot of music and video title data, and is rotated by a spindle motor 9.

  In the disk reproducing apparatus 10, eight optical heads 3a, 3b, 3c, 3d, 3e, 3f, 3g, 3h are 0 degrees as viewed from the rotation center of the optical disk 1 loaded on the mechanical deck unit 20, In the directions of 45 degrees, 90 degrees, 135 degrees, 180 degrees, 225 degrees, 270 degrees, and 315 degrees, they are provided radially at an angular interval of 45 degrees.

  The optical head 3a is attached to the sled 5a, and is configured to be movable along the sled shaft 7a in the radial direction of the optical disc 1 from the innermost peripheral portion to the outermost peripheral portion by the sled motor 6a. . The optical heads 3b to 3h are also attached to the sleds 5b to 5h, respectively, and can be moved in the radial direction of the optical disc 1 from the innermost peripheral part to the outermost peripheral part by the sled motors 6b to 6h. The

  Read outputs of the optical heads 3a to 3h are respectively supplied to RF amplifiers 41a to 41h, and focus error signals, tracking error signals, and recording data are obtained from the RF amplifiers 41a to 41h.

  The focus error signal and tracking error signal are supplied to the servo controller 30, and focusing and tracking of the optical heads 3 a to 3 h are controlled by the focus servo control signal and tracking servo control signal from the servo controller 30.

  The recorded data is demodulated and error-corrected by the demodulation circuits 42a to 42h, respectively. As the recording data, address information recorded on the optical disc 1, content index information such as TOC (Table Of Contents), and content data such as music data and video data are obtained.

  The address information and the content index information are taken into the system controller 50 and used for accessing the optical disc 1 by the drive control of the spindle motor 9 and the sled motors 6a to 6h by the servo controller 30.

  The content data from the demodulation circuits 42a to 42h is distributed by the channel distribution circuit 43 to a maximum of 8 channels as will be described later.

  The distributed content data of each channel is decoded by the decoding unit 44 to obtain reproduction outputs PB1, PB2,.

  The system controller 50 includes a CPU 51, a program such as a later-described access request response processing routine and a head operation history recording processing routine executed by the CPU 51, a ROM 52 in which various fixed data are written, a RAM 53 in which programs and data are expanded, a head A clock circuit 54 for measuring the operating time and head operating date and time, and a memory 55 are connected to the bus 56.

  The memory 55 is a nonvolatile memory in which a head operation history is recorded. An operation unit 61 and a display unit 63 are connected to the system controller 50.

  FIG. 2 shows an example of a disc playback system including the disc playback device having the above-described configuration. The disc playback device 10 shown in FIG. 1 is used as an in-vehicle music playback system or a video / audio playback system used in a house. , And terminals 101, 102,... 108 for each channel.

  In the disc reproducing apparatus 10, reproduction outputs PB1, PB2,... PB8 of each channel are transmitted from the transmission / reception unit 70 to the terminals 101, 102,. As a means for communication between the disc playback apparatus 10 and the terminals 101 to 108, cable (wired) or wireless communication can be used. For example, in a car music playback system, a cable is used and used in a residence. In the video / audio reproduction system, wireless communication is used.

  In the terminal 101, the transmission / reception unit 91 receives the reproduction output PB1 of channel 1 transmitted from the disk reproduction device 10, the reproduction processing unit 92 processes the reproduction data, and an image is displayed on the display 96, and the speaker. Audio is output from 97 or headphones. In the other terminals 102 to 108, the video is displayed on the display 96 with the same configuration, and sound is output from the headphones 98 or the speakers. However, in the music playback system, only voice (music) is output.

  Each of the terminals 101 to 108 includes a controller 93 that controls the transmission / reception unit 91 and the reproduction processing unit 92, and an operation unit 94 and a display unit 95 are connected thereto.

  The operation of accessing each of the channels (each user) to the optical disc 1 on the disc reproducing apparatus 10 and other operations are performed by the operation unit 94 of the terminals 101 to 108. A command such as an access command by the operation is transmitted from the controller 93 to the transmission / reception unit 91, and is transmitted to the disc playback apparatus 10 by the transmission / reception unit 91. In the disc reproducing apparatus 10, the transmitted command is received by the transmission / reception unit 70 and taken into the system controller 50.

  However, in the in-vehicle music playback system, for example, each user in the vehicle desires to the system controller 50 of the disc playback apparatus 10 by the operation of the operation unit 61 of the disc playback apparatus 10 by the passenger in the passenger seat. It is also possible to configure the system so that a song can be designated, playback of the song can be instructed, and the song can be heard by the terminals 101-108.

  In this case, for example, assuming that the terminal 101 is for a user who listens to music at the front seat of the car, the speakers 97 are provided at the left and right positions of the front seat, and the terminals 102 to 108 are users who listen to music at the back seat of the car Shall be for.

(Disc playback method: FIGS. 3 to 6)
In the disk reproducing apparatus 10 of the above-described example, when an access request to the optical disk 1 is made, the CPU 51 of the system controller 50 accepts the access request as follows, and accesses from the optical heads 3a to 3h. One optical head responding to the request is selected, and the optical head is caused to read the data instructed by the access request from the optical disk 1.

  FIG. 3 shows an example of an access request response processing routine executed by the CPU 51. In the access request response processing routine 130 of this example, first, in step 131, it is determined whether or not there is an access command (access request). If there is an access command, the process proceeds to step 132 and the access command is stored in the RAM 53. , The access command is accepted, and the process further proceeds to step 133 to determine whether there is a free optical head.

  “Free” is a state in which the disk is not in operation, that is, a state in which the track on the optical disk 1 is not moved in the radial direction of the optical disk 1 and data is not read from the track.

  If there is a free optical head, the process proceeds from step 133 to step 134, the optical head responding to the access command is selected, and the optical head is caused to execute the access indicated by the access command. If there is no free optical head, the process proceeds from step 133 to step 135 to execute another process described later.

  The head selection at step 134 is executed by the following head selection process. FIG. 4 shows an example of the head selection processing routine.

  In the head selection processing routine 140 of this example, first, in step 141, a later-described head operation history table recorded in the memory 55 is referred to, and then the process proceeds to step 142. From the reference result, the past operation time is determined. Detects the shortest optical head and proceeds to step 143 to determine whether or not there is one detected optical head.

  At the beginning of the purchase of the disk reproducing apparatus 10, the past operating times of the optical heads 3a to 3h are all zero. Immediately after that, after a certain optical head is selected and operated by the method described later. However, the past operating time of the remaining seven optical heads is zero. On the other hand, when the disk reproducing apparatus 10 is used for a certain period of time or more, as will be described later, a difference occurs in the past operating time of the optical heads 3a to 3h.

  Then, when it is determined in step 143 that there are a plurality of optical heads having the shortest operating time in the past as in the initial use of the disk reproducing apparatus 10, the process proceeds to step 144 to be described later. According to the method, one of the plurality of optical heads is selected as an optical head responding to the access command, and the head selection process is terminated.

  On the other hand, if it is determined in step 143 that there is only one optical head with the shortest operating time in the past, the process proceeds to step 145 to select that one optical head as the optical head that responds to the access command. The head selection process ends.

  FIG. 5 shows an example of the head operation history table recorded in the memory 55. In this example, as the head operation history table, the current state, the most recent operation date and time, the past operation count, and the past operation time are recorded for each of the optical heads 3a to 3h.

  The current state indicates whether or not the optical head is currently operated by a status flag. When the optical head is currently operated, the status flag is set to 1. When the optical head is not currently operated, the status flag is set to 0. It is said.

  The operation date / time is the date / time at the operation start time (seek start time) or the operation end time (reading end time) at the time of purchase, and when the disc player 10 is initially purchased, the setting date / time is determined by initial setting by the manufacturer or user. Are recorded as the most recent operation date and time for all of the optical heads 3a to 3h.

  The past operation time is the sum of the operation times at the time of each past operation, and one operation time is a seek time (the optical head is moving in the radial direction of the optical disk 1 to access the indicated track). And the reading time (the time during which the optical head is reading data from the designated track).

  In step 144 of the head selection processing routine 140 of FIG. 4, an optical head that responds to the access command is selected by one of the following methods.

  In the first method, one optical head selected in a cyclic order is selected as an optical head that responds to the access command from among the optical heads that have the shortest operating time in the available optical heads. .

  In the second method, one optical head selected at random is selected as an optical head that responds to the access command from among the optical heads that have the shortest operating time in the available optical heads.

  In the first method, at the beginning of use of the disk reproducing apparatus 10, the optical head 3a → the optical head 3b → the optical head 3c → the optical head 3d → the optical head 3e → the optical head 3f → the optical head 3g → the optical head 3h. However, since the data length (time length) of individual songs and video titles read by the selected optical head varies and the seek time also varies depending on the playback, disc playback for some time or more When the apparatus 10 is used, a difference occurs in the past operation time of the optical heads 3a to 3h, the number of heads in the selection range is reduced, and an optical head with the shortest past operation time is always selected. The past operating times of the optical heads 3a to 3h are equalized.

  In the second method, at the beginning of use of the disk reproducing device 10, the number of operations of the optical heads 3a to 3h may be biased and the operation time may be uneven, but the disk reproducing device 10 is used for a certain time or more. Then, as in the first method, the past operating times of the optical heads 3a to 3h are equalized.

  FIG. 6 shows an example of a head operation history recording processing routine executed by the CPU 51 of the system controller 50.

  In the head operation history recording processing routine 150 of this example, in step 134 of the access request response processing routine 130 of FIG. 3, that is, in step 144 or 145 of the head selection processing routine 140 of FIG. By selecting the responding optical head, the head operation history recording process is started. First, in step 151, the status flag for the selected optical head is set to 1, and then the process proceeds to step 152 where the selected head is selected. The most recent operation date and time for the optical head is updated to the date and time at that time, and then the process proceeds to step 153 to increment the past number of operations for the selected optical head by one.

  Next, the process proceeds to step 154, where it is determined whether or not the operation of the selected optical head has been completed (data reading has been completed). When the operation has been completed, the process proceeds from step 154 to step 155. The operation time is calculated once, the past operation time for the selected optical head is updated, and the process proceeds to step 156 to set the status flag for the selected optical head to 0.

  In the disk reproduction system of the above-described example, the number of optical heads and the number of channels of the access request source (reproduction output transmission destination) are the same, but the optical heads 3a to 3h are fixedly associated with the channels. Instead, an optical head that responds to an access request is selected depending on the occasion.

  In this case, the “no vacant optical head” state shown in the access request response processing routine 130 in FIG. 3 means that there are access requests from all channels 1 to 8 and the optical heads 3a to 3 3h is in a state where all are operated.

  In this state, when there is another access request from a certain channel among the channels 1 to 8, that is, for example, when an access command requesting reproduction of another song is issued, the access shown in FIG. In step 135 of the request response processing routine 130, another process is executed for the access command.

  Specifically, as another process, access requests are concentrated on the display unit 63 of the disc playback apparatus 10 for the channel or on the display unit 95 of the terminal of the channel, and the access request is immediately responded. It is displayed that it cannot be done. In this case, when the operation of one of the optical heads is completed while holding the access command, the optical head is selected as the optical head responding to the access command, and the access request is made. respond.

  The example described above is a case where the optical head having the shortest operating time in the available optical heads is selected as the optical head responding to the access command, but the steps of the head selection processing routine 140 in FIG. In 142, an optical head having the smallest number of past operations is detected from the available optical heads, that is, as a head selection process, the light having the smallest number of past operations in the available optical head is used. The disk reproducing apparatus 10 may be configured to select the head as an optical head that responds to the access command.

  In this case, the optical head is selected so that the past number of operations of the optical heads 3a to 3h is made uniform, but the disk reproducing apparatus 10 is used for a certain period of time and the optical heads 3a to 3h. When the number of past operations increases beyond a certain level, variations in the data length (time length) of individual songs and video titles and variations in seek times during playback are absorbed, and the optical heads 3a to 3h The past operation time is also equalized, and as a result, the optical head is selected so that the past operation time of the optical heads 3a to 3h is equalized.

  Further, in step 134 of the access request response processing routine 130 shown in FIG. 3, the vacant optical heads are selected in a cyclic order or randomly from the available optical heads without using the head selection processing routine as shown in FIG. The disc reproducing apparatus 10 may be configured to select one optical head (if there is only one free optical head, that one optical head) as the optical head that responds to the access command.

  Also in this case, when the disk reproducing apparatus 10 is used for a certain period of time, the past operation times of the optical heads 3a to 3h are equalized, and the past operation times of the optical heads 3a to 3h are equalized. It becomes like this.

  Note that the number of channels of the access request source (reproduction output transmission destination) may be larger than the number of optical heads provided in the disk reproduction apparatus. For example, when eight optical heads 3a to 3h are provided as in the disk reproducing apparatus 10 of FIG. 1, the number of access request source channels may be set to ten.

  In this case, for example, when there is an access request from the channels 1 to 8 and all the optical heads 3a to 3h are operating, and there is an access request from the channel 9, the CPU 51 of the system controller 50 exceptionally , One of the optical heads 3a to 3h is selected as an optical head that responds to a two-channel access request, that is, the channel X that is actually responding to the access request and the channel 9 that is newly requesting the access request. The head is caused to execute multi-channel reproduction by multi-access as shown in FIG.

  However, in this case, not only the optical head responding to the two-channel access command but also other optical heads, as shown in FIG. 10, data is read from the optical disk 1 at high speed and stored in the buffer memory. It is necessary to transfer and accumulate and to read data from the buffer memory at a rate lower than the transfer rate.

  As the optical head that responds to the two-channel access command, it is desirable to configure the disc reproducing apparatus 10 so as to select the optical head that is accessing the track closest to the track designated by the new access request. According to this, the seek time between channels as shown in FIG. 10 can be reduced.

  As described above, when there is an access request from the channel 10 while responding to the access requests of the channels 1 to 9, the CPU 51 of the system controller 50 is exceptional as in the case of the access request from the channel 9. In addition, the one not responding to the access request of the channel 9 in the optical heads 3a to 3h is changed to the access request of the two channels of the channel Y which is actually responding to the access request and the channel 10 which is newly requested to access. The optical head is selected as a responding optical head, and the optical head is caused to execute multi-channel reproduction by multi-access as described above.

[Second Embodiment of Disc Playback Device and Disc Playback Method: FIGS. 7 and 8]
(Configuration of disc playback apparatus and disc playback system: FIG. 7)
For example, when the disc playback system is configured as the above-described in-vehicle music playback system, the number of channels may actually be about several channels. Therefore, in such a case, for example, when eight optical heads 3a to 3h are provided as in the disk reproducing apparatus 10 of FIG. 1, the optical heads responding to the access request from these optical heads 3a to 3h. It is preferable that two optical heads are selected and data is read by the two optical heads as follows.

  FIG. 7 shows an example of the disk reproducing apparatus in this case. The mechanical deck unit 20 is the same as the example of FIG. 1 including the point that eight optical heads 3a to 3h are provided. Reading outputs of the optical heads 3a to 3h are supplied to the RF amplifiers 41a to 41h, recording data from the RF amplifiers 41a to 41h are supplied to the demodulation circuits 42a to 42h, focusing and tracking of the optical heads 3a to 3h The configuration of the system controller 50 is also the same as the example of FIG.

  In this example, the data from the demodulation circuits 42a to 42h is distributed by the channel distribution circuit 43 to a maximum of four channels as will be described later.

  The distributed data of each channel is decoded by the decoding unit 44 to obtain reproduction outputs PB1 to PB4 of up to four channels as will be described later.

  As a disk playback system, for example, an in-vehicle music playback system is provided with four terminals as shown in FIG. 2, that is, for four channels.

(Disc playback method: Fig. 8)
In the disk reproducing apparatus 10 of FIG. 7, when there is an access request to the optical disk 1, the CPU 51 of the system controller 50 uses two optical heads from among the available optical heads as optical heads that respond to the access command. Select.

  Specifically, in this case, the access request response processing routine selects two optical heads as optical heads responding to the access command in step 134 of the access request response processing routine 130 in FIG. In step 142 of the head selection processing routine 140 in FIG. 3, the processing routine detects two optical heads with the shortest past operating time (the optical head with the shortest past operating time and the second shortest optical head). Alternatively, two optical heads having the smallest number of past operations (an optical head having the smallest number of past operations and an optical head having the second smallest number) are detected.

  Alternatively, as in the first embodiment described above, in step 134 of the access request response processing routine 130 shown in FIG. 3, it is not necessary to use the head selection processing routine shown in FIG. The two selected optical heads (or two optical heads when there are only two free optical heads) as the optical heads responding to the access command in a specific order or randomly. In addition, the disk reproducing apparatus 10 may be configured.

  Then, the two selected optical heads are caused to read different portions of the music and video title data, specifically, the first half and the second half almost simultaneously.

  For example, in the case of a music playback system, if the two selected optical heads are the optical heads 3a and 3e, the optical head 3a is instructed by an access request as shown in FIG. At the same time, the head of the portion where the data of the first half of the song is recorded in one track is accessed, and at the same time, the optical head 3e is moved to the portion where the data of the second half of the song is recorded. The head is accessed, and from this state, the data of the first half of the music is read by the optical head 3a, and the data of the second half of the music is read by the optical head 3e. It should be noted that it is desirable to divide the first half and the second half of the song into sectors.

  Then, in the decoding unit 44 of the reproduction processing unit 40, as shown in FIG. 8B, the first half of the data is output without being written to the delay buffer memory, and the second half of the data is the delay data. By writing to the buffer memory and reading from the buffer memory, the data of the first half of the music is outputted with a delay, and as a result, the music data is reproduced in the original time series.

  According to this method, the time required to read one piece of content data from the optical disc 1 can be reduced to almost ½, and a large vibration of the vehicle body occurs within the period shown as the reading period in FIG. As long as there is no cause for trouble in reading data, content data can be played back even during the period indicated as the read period, even if there is a cause for trouble in reading data. Can be halved.

[Other Embodiments]
The disk medium on which content data such as music data and video data is recorded is not limited to an optical disk, but may be a magnetic disk or a magneto-optical disk. The content data recorded on the disk medium is not limited to music data or video data, but may be a computer program such as game software.

It is a figure which shows the 1st example of the disc reproducing | regenerating apparatus of this invention. It is a figure which shows an example of the disc reproduction | regeneration system of this invention. It is a figure which shows an example of an access request response process routine. It is a figure which shows an example of a head selection process routine. It is a figure which shows an example of a head operation history table. It is a figure which shows an example of a head operation history recording process routine. It is a figure which shows the 2nd example of the disc reproducing | regenerating apparatus of this invention. It is a figure where it uses for description of the reproducing method in the disc reproducing | regenerating apparatus of FIG. It is a figure which shows the access operation in the case of multi access. It is a figure which shows the data reproduction | regeneration in the case of multi access.

Explanation of symbols

  Since all the main parts are described in the figure, they are omitted here.

Claims (7)

A method of reading data from a disk medium with a disk playback device comprising a plurality of read heads that can be operated independently of each other and movable in the radial direction of each loaded disk medium,
When access to the disk medium is requested, from non-operating read heads in the plurality of read heads according to a criterion for averaging the operating time or number of times of the plurality of read heads, or cyclically A head selection step of selecting a read head that responds to the access request in order or randomly;
Allowing the selected read head to access the disk medium and causing the selected read head to read data; and
A disc playback method comprising: The disc playback method according to claim 1, wherein
In the head selection step, a plurality of read heads that are smaller than the total number of read heads provided in the disk reproducing device are selected as read heads that respond to the access request, and in the access step, the selected plurality of read heads A disc reproducing method for causing a different portion in data designated by the access request to be read. A mechanical deck unit having a plurality of read heads that can be operated independently of each other and movable in the radial direction of each loaded disk medium;
A reproduction processing unit for processing data read from the disk medium by the read head;
A control unit for controlling the mechanical deck unit and the reproduction processing unit,
The control unit, when access to the disk medium is requested, from the non-operated read heads in the plurality of read heads according to a standard for averaging the operation time or the number of operations of the plurality of read heads Or a head selection step of selecting a read head that responds to the access request in a cyclic order or at random, and the selected read head is accessed on the disk medium, and the selected read head And a disk reproducing apparatus for executing an access process for reading data. The disc player according to claim 3, wherein
The control unit selects a plurality of read heads smaller than the total number of read heads included in the disk reproducing device as read heads responding to the access request in the head selection step, and the selection is performed in the access step. And a disc reproducing apparatus that causes a plurality of read heads to read different portions in the data indicated by the access request. The disc player according to claim 3, wherein
A storage unit that records the past operation time or the number of operations for each of the plurality of read heads;
Each time the control unit selects a read head that responds to the access request in the head selection step, the control unit updates a past operation time or the number of operations for the selected read head.   6. A disc playback system comprising the disc playback apparatus according to claim 3, 4 or 5, and a terminal for receiving a playback output obtained from the playback processing section. In order to read data from the disk medium with a disk playback device comprising a plurality of read heads that can be operated independently of each other and are movable in the radial direction of the loaded disk medium,
When access to the disk medium is requested, from non-operating read heads in the plurality of read heads according to a criterion for averaging the operating time or number of times of the plurality of read heads, or cyclically Means for selecting a read head responding to the access request, in order or randomly; and
Means for causing the selected read head to access the disk medium and causing the selected read head to read data;
Access request response program to function as

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