JPH11126410A - Disk reproducing device and data reproducing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the reproducing output speed of data based on a read- command. SOLUTION: A latter half first reading operation, in which reading operation RD1 from a halfway position of a read-out section to the finish position is first performed, and successively, a reading operation RD2 from the start position to a halfway position is performed, is performed, after data read out by the latter half first reading operation is accumulated, and the data is outputted as data from the start position of a read-out section to the finish position. Or, the latter half read-out operation from the halfway position of the read-out section to the finish position is performed, data from the start position of the read-out section to the finish position are made by correction-processing an error of data read out by this latter half reading operation, and data are outputted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk reproducing apparatus capable of performing a reproducing operation for a disk-shaped recording medium.

[0002]

2. Description of the Related Art CD (Compact Disc) type discs as optical disc recording media and DVD (Digital Versatile Disc / Digital) suitable for multimedia applications.
Discs called VideoDisc) have been developed. In a reproducing apparatus corresponding to these optical discs, data is read by irradiating a track on the disc with laser light and detecting the reflected light.

Tracks TK on the disk are formed, for example, in a spiral form from the inner peripheral side to the outer peripheral side of the disk, as schematically shown in FIG. When the disk is rotated, laser light from the reproducing device is irradiated along the spiral track, and data is read.

[0004]

By the way, in a reproducing apparatus for performing a disk reproducing operation in response to a read command (data transfer request) from a host computer and transmitting the reproduced data to the host computer, for example, It is required to perform data transfer promptly. The read command includes data as a normal read command, a start position as a transfer request data section, and a data length from the start position. That is, the host computer specifies a playback command and a section to be played back.

As an operation of the reproducing apparatus when such a read command is generated, first, a seek operation of the optical head is executed in order to read a requested data section together with the read command. That is, this is a seek operation for reading data from a start position of a data section requested to be transferred by a read command (hereinafter, referred to as a transfer request start position). After the seek is completed, data reading is started from the time when the transfer request start position is reached, and the reading operation is performed up to the end position of the data section requested to be transferred by the read command (hereinafter, referred to as a transfer request end position). As described above, data is read from the transfer request start position to the transfer request end position, necessary decoding processing and error correction processing are performed, and the requested data is transferred to the host computer.

One of the causes of such an operation delay is a standby time from the end of the seek operation to the point where the transfer request starts. FIG. 17 illustrates the delay in processing due to the standby time. FIG. 17 shows a part of a spiral track TK on the disk, and as shown, a transfer request start position TGS to a transfer request end position TGE.
It is assumed that data reading up to is requested. The seek operation of the optical head is performed with a range from the transfer request start position TGS to a position just before one round of the track as a target position. Now, the position of the spot of the laser beam at the time when the seek operation has been completed (hereinafter referred to as a seek landing point) is the position indicated by SE in the drawing which is within the range from the transfer request start position TGS to one turn before the track turns. Suppose.

In this case, as shown by the broken line, the read standby W is maintained until the spot reaches the transfer request start position TGS.
Becomes In this case, the rotation time for about ／ of the disk becomes the standby time. And the spot is the transfer request start position T
GS, the transfer request end position T as shown by the thick line
The read operation RD up to GE is executed. In other words, in this case, the time required for the disk to rotate about ／ turns becomes a useless time, and the data transfer to the host computer is delayed by the waiting time (latency). Such a rotation wait is the time required for the disk to make a rotation of less than about one round at the maximum, depending on the positional relationship between the seek landing point and the transfer request start position TGS.

[0008]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention provides a disk reproducing apparatus for performing a reproducing operation on a disk-shaped recording medium having tracks formed in a spiral shape. An object of the present invention is to eliminate a delay in a reproducing operation due to a waiting time.

For this purpose, the reproduction control means of the reproducing apparatus, when a specific condition is satisfied in response to a data request in which the read section is specified, the first control from the middle position to the end position of the read section. The read operation is performed first, and then the second read operation from the start position to the middle position of the read section is performed. The second read operation is controlled so that the data read means and the read position control means execute the latter read operation. After accumulating data read by the second half prefetching operation in the data output means, the data is output as data from the start position to the end position of the read section. Specific conditions for executing the second half prefetch operation include that the read section is a section within one round track, and even if a track jump required for the second half prefetch operation is performed, the first in the second half prefetch operation is performed. It is determined that the period from the start of the read operation to the end of the second read operation can be completed within a period of one rotation of the disk. In other words, in the present invention, the section which can be read by performing the track jump is read first during the disk rotation waiting period, thereby eliminating the processing delay caused by the disk rotation waiting.

[0010] Alternatively, the reproduction control means of the reproducing apparatus may perform a second half read operation from a middle position to an end position of the read section when a specific condition is satisfied in response to a data request in which the read section is specified. Is performed by the data reading means and the reading position control means, and the data output means performs an error correction process on the data read by the latter half reading operation. When the data from the start position to the end position is obtained, the data output means outputs the data from the start position to the end position of the read section. A specific condition for performing the second half reading operation is that it is determined that data from the start position to the middle position of the reading section can be generated by an error correction process using data read in the second half reading operation. In other words, according to the present invention, a section that can be read by performing a track jump is read during the conventional disk rotation waiting period.
And by the error correction processing of the read data,
If the data of the section that has not been read (data from the start position to the middle position of the read section) can be generated, the reading of that part does not have to be executed. In addition, the reading operation itself can be completed in a short time.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a disk reproducing apparatus using an optical disk as a recording medium will be described as first to fourth embodiments of the present invention. The optical disc loaded in the disc reproducing apparatus of these examples is, for example, a CD-DA (COMPAC
CD discs such as T DISC DIGITAL AUDIO) and CD-ROM, and DVD (DIGITAL VERSATILE DISC / DIGI)
A disk called "TAL VIDEO DISC" can be considered. Of course, the present invention can be applied to a disc reproducing apparatus corresponding to other types of optical discs. The first
The disk playback devices according to the fourth to fourth embodiments have the same device configuration. The device configuration is described with reference to FIG. 1 only in the description of the first embodiment, and the description of the second to fourth embodiments is made. The description of the device configuration will be omitted.

<First Embodiment> FIG. 1 is a block diagram of a main part of a disk reproducing apparatus according to the present embodiment. Disk 90
Are loaded on a turntable 7 and are rotationally driven at a constant linear velocity (CLV) or a constant angular velocity (CAV) by the spindle motor 1 during a reproducing operation. The pickup 1 reads data recorded on the disk 90 in the form of embossed pits or phase change pits. In the pickup 1, a laser diode 4 serving as a laser light source, a photodetector 5 for detecting reflected light, an objective lens 2 serving as an output end of the laser light, and a laser beam are irradiated on the disk recording surface via the objective lens 2. Further, an optical system for guiding the reflected light to the photodetector 5 is formed. The objective lens 2 is held by a biaxial mechanism 3 so as to be movable in a tracking direction and a focus direction. The entire pickup 1 can be moved in the disk radial direction by a thread mechanism 8.

The information on the reflected light from the disk 90 is detected by the photodetector 5, converted into an electric signal corresponding to the amount of received light, and supplied to the RF amplifier 9. The RF amplifier 9 includes a current-voltage conversion circuit, a matrix operation / amplification circuit, and the like corresponding to output currents from a plurality of light receiving elements as the photodetector 5, and generates necessary signals by matrix operation processing. For example, it generates an RF signal as reproduction data, a focus error signal FE for servo control, a tracking error signal TE, and the like. The reproduction RF signal output from the RF amplifier 9 is supplied to a binarization circuit 11, and the focus error signal FE and the tracking error signal TE are supplied to a servo processor 14.

The reproduced RF signal obtained by the RF amplifier 9 is 2
By being binarized by the value conversion circuit 11, it is converted into a so-called EFM signal (8-14 modulated signal; in the case of CD) or an EFM + signal (8-16 modulated signal; in the case of DVD), and supplied to the decoder 12. The decoder 12 performs EFM demodulation, error correction processing, and the like.
The information read from the disk 90 is reproduced by performing OM decoding, MPEG decoding, and the like.

The decoder 12 accumulates the data subjected to the EFM demodulation in a data buffer 20 as a memory unit, and performs an error correction process and the like on the data buffer 20. In the case of this example, the data order read from the disk 90 in the latter half prefetch operation described later may be different from the normal order, but the data stream as all data to be reproduced and output is read from the disk 90. It is constructed on the data buffer 20 regardless of the data order. That is, as read data, necessary processing such as error correction processing is performed while data read from the disk 90 is accumulated in the data buffer 20, and is formed as a predetermined data stream.

The interface section 13 is connected to an external host computer and communicates reproduction data and read commands with the host computer. That is, the reproduced data constructed on the data buffer 20 is output to the host computer via the interface unit 13. A read command and other signals from the host computer are supplied to the system controller 10 via the interface unit 13.

The servo processor 14 detects various focus, tracking, sled, and spindle servo drives based on a focus error signal FE and a tracking error signal TE from the RF amplifier 9 and a spindle error signal SPE from the decoder 12 or the system controller 10. A signal is generated to execute a servo operation. That is, the focus error signal FE and the tracking error signal T
A focus drive signal and a tracking drive signal are generated according to E and supplied to the two-axis driver 16. The two-axis driver 16 drives the focus coil and the tracking coil of the two-axis mechanism 3 in the pickup 1. As a result, a tracking servo loop and a focus servo loop are formed by the pickup 1, the RF amplifier 9, the servo processor 14, the two-axis driver 16, and the two-axis mechanism 3.

The servo processor 14 sends a spindle error signal SP to the spindle motor driver 17.
The spindle drive signal generated according to E is supplied. The spindle motor driver 17 applies, for example, a three-phase drive signal to the spindle motor 6 according to the spindle drive signal, and executes the CLV rotation of the spindle motor 6. Further, the servo processor 14 generates a spindle drive signal in response to a spindle kick / brake control signal from the system controller 10, and causes the spindle motor driver 17 to execute operations such as starting or stopping the spindle motor 6.

The servo processor 14 generates a thread drive signal based on, for example, a thread error signal obtained as a low-frequency component of the tracking error signal TE or an access execution control from the system controller 10 and supplies the thread drive signal to the thread driver 15. . The thread driver 15 responds to the thread drive signal by the thread mechanism 8.
Drive. Although not shown in the thread mechanism 8, a main shaft for holding the pickup 1, a thread motor,
The pickup 1 has a required sliding movement by having a mechanism such as a transmission gear and driving the sled motor 8 by the sled driver 15 according to the sled drive signal.

The laser diode 4 in the pickup 1 is driven by a laser driver 18 to emit laser light. The system controller 10 sets the control value of the laser power in the auto power control circuit 19 when executing the reproducing operation on the disc 90, and the auto power control circuit 19 performs the laser output according to the set laser power value. The laser driver 18 is controlled so as to be operated.

When the apparatus is capable of performing a recording operation, a signal modulated according to recording data is applied to the laser driver 18. For example, when recording is performed on a recordable type disc 90, the recording data supplied from the host computer to the interface unit 13 is added with an error correction code by an encoder (not shown),
After processing such as EFM + modulation is performed, the data is supplied to the laser driver 18. Then, the laser driver 18 causes the laser diode 4 to perform a laser emission operation according to the recording data, so that data recording on the disk 90 is performed.

Various operations such as servo, decoding and encoding as described above are controlled by a system controller 10 formed by a microcomputer.
For example, as a series of playback operation control, the system controller 10 issues a command to the servo processor 14 as an operation for reading a requested data section in response to a read command from the host computer, and issues a transfer request by the read command. The seek operation of the pickup 1 targeting the transfer request start position as the data section thus performed is executed. As will be described later in detail, after the end of the seek, all or a part of the data section from the transfer request start position to the transfer request end position is read, and the decoder 1
2. Control the data buffer 20 to execute necessary processing and transfer the reproduction data (requested data) from the transfer request start position to the transfer request end position from the interface unit 13 to the host computer.

The processing when a read command is issued from the host computer in such a disk reproducing apparatus will be described with reference to FIGS. FIG. 2 shows a control process of the system controller 10 when a read command is generated. FIGS. 3 to 5 show operations on the track TK of the disk 90 in various cases realized by the control of the system controller 10. Is schematically shown.

When a read command is generated, the processing of the system controller 10 proceeds to step F101 in FIG. 2, and firstly, a seek operation is performed for a specified request data range (a head address and data length to be read) together with the read command. . In this case, the seek target is set at a transfer request start position as a target, and is within a range of one track before the transfer request start position. By setting such a seek target to the servo processor 14 as a seek operation and issuing an instruction, the movement of the pickup 1 by the sled mechanism 8 and the movement of the objective lens 2 by the biaxial mechanism 3
By the track jump, the position of the laser spot is moved to a range one track before the transfer request end position. Upon completion of such a seek operation, the process proceeds from step F102 to F103, and then proceeds to step F103.
In 103 and F104, it is determined whether or not to execute the latter half prefetch operation, which is a characteristic operation of this example.

First, in step F103, as a data range (one or a plurality of data sectors) requested to be transferred, it is determined whether or not the data length from the start position of the transfer request to the end position of the transfer request is within the range of one track orbit. I do. Also,
In the case of performing the latter half prefetching operation, it is necessary to perform the track jump twice after the seek is completed.
Then, it is determined whether or not an effective second half prefetch operation can be realized even if the track jump is performed twice. This step F
The reason for the judgment of 103 and F104 will be described later,
Only when a positive result is obtained as a result of these determinations, the process proceeds to step F105 to execute the latter half prefetch operation.

When performing the latter half prefetching operation, first, in step F105, a track jump of one track is performed toward the outer peripheral side. FIG. 3 shows the latter half prefetching operation. The track jump TJ1 to the outer peripheral side shown in FIG. 3 is executed as the operation of step F105 from the seek landing point SE within one track on the inner peripheral side from the transfer request start position TGS. Then, the track jump destination is located in the middle of the data range to be read, and in step F106, the operation RD1 of reading data from this middle position is started. Of course, the read data is subjected to decoding, error correction processing, and the like, and is accumulated in the data buffer 20.

As the read operation RD1, the transfer request end position T
Upon completion of the reading up to the GE, the process proceeds to Step F107
Then, the process proceeds to F108 to execute a track jump TJ2 toward the inner peripheral side as shown in FIG. Then, the position of the track jump destination is a point before the transfer request start position TGS, and therefore, as shown as read standby W, it waits until the laser spot reaches the transfer request start position TGS.
That is, the disk rotation wait is performed for a short time. Then, when the transfer request start position TGS is reached, the process proceeds from step F109 to F110 to perform an operation RD2 of reading data from the transfer request start position TGS.
The read data is subjected to decoding, error correction processing, and the like, and is accumulated in the data buffer 20.

This read operation RD2 is performed up to the position immediately before the start of data read by read operation RD1.
That is, the read operation is performed until all data in the range from the transfer request start position TGS to the transfer request end position TGE can be accumulated in the data buffer 20. As the read operation RD2 in step F110, the read operation RD1
Performs data reading in the range where data was not read,
When reading of all the data in the requested range is completed, the process proceeds from step F111 to F112, and the data in the requested data range stored in the data buffer 20 at that time is transferred to the host computer.

That is, by such a second half prefetch operation, the transfer request start position TG is conventionally shifted from the seek landing point SE.
During the period of waiting for the disk rotation to the position S, the latter half of the data range to be read as the read operation RD1 is read first. Then, when the disk rotation has progressed and the reading to the transfer request end position TGE is completed, jump back to just before the transfer request start position TGS, and then perform the read operation RD2. , And can be completed efficiently without performing unnecessary rotation waiting. As a result, faster data transfer to the host computer can be realized.

By the way, in some cases, the disk rotation waiting time cannot be eliminated by such a second half prefetching operation.
Alternatively, a negative result is obtained in F104. For example, FIG.
Is the transfer request start position TGS to the transfer request end position TG
An example is shown in which the data length up to E is one or more tracks. That is, a negative result is obtained in step F103. In such a case, a track jump is temporarily performed from the seek landing point SE to the outer periphery of one track as indicated by a wavy arrow, and the latter half of the requested data range is read from there to the transfer request end position TGE,
Further, assuming that a track jump is performed to the inner circumference side as indicated by a wavy arrow after the reading to the transfer request end position TGE is completed, the jumped back position is not immediately before the transfer request start position TGS. Therefore, in this case, it is necessary to further perform a one-track jump to the inner peripheral side and then wait for the disk rotation until the transfer request start position TGS is reached. Can not be resolved.

Accordingly, when it is determined that the data length from the transfer request start position to the transfer request end position is not within the range of one track rotation, the process proceeds from step F103 to F109, and the read standby W is set as shown in FIG. In this state, it waits until the transfer request start position TGS is reached. Then, when the laser spot reaches the transfer request start position TGS, the process proceeds to step F
Proceeding to 110, an operation RD7 of reading data from the transfer request start position TGS is performed. In this case, the transfer request end position T
At the point in time when reading up to GE has been completed, it is determined in step F111 that reading of all requested data has been completed, and the process proceeds to step F112 in which data in the requested data range accumulated in the data buffer 20 is stored in the host. Will be transferred to the computer.

FIG. 5 shows an example in which an effective second half prefetch operation cannot be realized even if two track jumps are performed for the second half prefetch operation. When the latter half prefetch operation is performed as described with reference to FIG.
1. Two track jumps, TJ2, are required. However, if the positional relationship between the seek landing point SE and the transfer request start position TGS is as shown in FIG. 5, a track jump is temporarily performed from the seek landing point SE to the outer circumference of one track as indicated by a wavy arrow, and transfer is performed from there. If the latter half of the requested data range is read up to the request end position TGE, and further the track jump is performed to the inner circumference side as indicated by a wavy arrow after the reading up to the transfer request end position TGE, the jump back is performed. This position does not come before the transfer request start position TGS. If it is not possible to jump back immediately before the transfer request start position TGS as described above, it is necessary to perform a further one-track jump to the inner circumference side and then wait for the disk rotation to reach the transfer request start position TGS. Even if you perform the operation,
The disk rotation waiting time cannot be eliminated effectively. That is,
Two read operations (reading of all data having a data length within one track of a track) as the latter half pre-read operation are performed on the disk 1
It will not be able to finish within the period of rotation. Although not shown, when the track jump is performed from the seek landing point SE to the outer periphery side, when the position after the track jump exceeds the transfer request end position TGE, the second half prefetch operation is effective. It does not work. Also in this case, the two read operations as the second half prefetch operation cannot be completed within a period of one rotation of the disk.

Therefore, in step F104, the track is tracked twice based on, for example, the positional relationship (address difference) between the seek landing point SE and the transfer request start position TGS and the positional relationship between the seek landing point SE and the transfer request end position TGE. If it is determined that an effective operation cannot be realized even if the second half prefetch operation for performing the jump is performed, that is, it is necessary to wait for the disk rotation at some timing after all, and all data must be read within one disk rotation. If it is determined that the process cannot be completed in step F109, the process proceeds to step F109, and waits for the transfer request start position TGS in the read standby W state as shown in FIG. Then, when the laser spot reaches the transfer request start position TGS, the process proceeds to step F110, and performs an operation RD8 of reading data from the transfer request start position TGS. In this case as well, when the reading to the transfer request end position TGE is completed, it is determined in step F111 that the reading of all the requested data has been completed, and the process proceeds to step F111.
Proceeding to 112, the data in the requested data range stored in the data buffer 20 is transferred to the host computer.

As described above, in the present embodiment, step F10
(3) According to the determination in F104, when the condition is satisfied, the second half prefetch operation is performed, whereby the data reproduction operation and the transfer process can be speeded up, and when the effect of the second half prefetch operation cannot be expected. Since the second half prefetch operation is not executed, an appropriate read operation is executed, and an optimal operation according to the situation is realized.

FIG. 6 shows a modification of the first embodiment. This is a modification of the process (jump-back timing) of step F107 in FIG. 2, and as shown in FIG. 3, in the above example, the transfer request end position TG
Jump back (track jump TJ2) is performed when the reading up to E is completed.
As shown in FIG. 6, when the position after the jump back becomes a point immediately before the transfer request start position TGS, jump back (track jump TJ3) is performed. That is, this is an example in which the order of the read standby W and the jump back are reversed. Even in such an operation, the same effect can be obtained as the latter half prefetch operation. Such a modification is also conceivable in the second to fourth embodiments described later.

<Second Embodiment> As a second embodiment, an operation when a read command is generated from a host computer will be described with reference to FIGS. FIG. 7 shows a control process of the system controller 10 when a read command is generated, and FIGS.
0 in various cases realized by the control of 0
The operation on the track TK of No. 0 is schematically shown.

When a read command is generated, the processing of the system controller 10 proceeds to step F201 in FIG. 7, and, as in the first embodiment, within a range of one track before the target transfer request start position. The seek operation is executed with the goal of. When the seek operation within one track from the transfer request start position TGS is completed as in the seek landing point SE in FIG. 8, the process proceeds from step F202 to F203, and the characteristic operation of the present example is described. It is determined whether or not the second half read operation should be performed.

The second half reading operation of this example is to read the second half of the requested data range and if the first half of the data that has not been read can be restored by the error correction processing, the first half is not read. This is the operation. Therefore, in step F203, a track jump is performed from the current seek landing point SE, and an error correction process using the read data from the middle position of the data range requested to be transferred, which is the position after the track jump, to the transfer request end position TGE. Then, it is determined whether or not the data in the unread section starting from the transfer request start position TGS can be restored. The determination in step F203 is based on the data length from the intermediate position, which is the position after the track jump from the seek landing point SE, to the transfer request end position TGE, the data length from the transfer request start position TGS to the intermediate position, and the playback device. Can be performed by comparing the error correction abilities. When a positive result is obtained as the determination in step F203, the process proceeds to step F205 to execute the latter half reading operation.

When executing the second half reading operation, first, in step F204, a track jump of one track is performed toward the outer periphery. That is, as shown in FIG. 8, the transfer request start position TG
A track jump TJ4 from the seek landing point SE within one track on the inner circumference side to S to the outer circumference side is executed. Then, the track jump destination is located in the middle of the data range to be read, and in step F205, the data read operation RD3 from this middle position is started. Of course, the read data is accumulated in the data buffer 20 while performing decoding, error correction processing and the like.

As the read operation RD3, the transfer request end position T
Upon completion of the reading up to the GE, the processing proceeds to step F206
Then, the process proceeds to F207 to determine an error correction result. That is, when the read operation RD3 is completed, even the data in the non-read section NR in which the reading is not actually performed can be restored by the error correction processing of the read data in the section, and all the necessary data to be transferred can be obtained. It is determined whether or not it has been performed. If all data has been obtained by the error correction processing, the process proceeds from step F207 to F212, and all data in the requested data range stored in the data buffer 20 at that time is transferred to the host computer.

That is, by such a second half reading operation,
Conventionally, during the disk rotation waiting from the seek landing point SE to the position of the transfer request start position TGS, the latter half of the data range to be read as the read operation RD3 is read, thereby eliminating unnecessary rotation waiting. .
Further, when all necessary data including the section where no reading is performed is obtained by the error correction processing of the read data, reading is performed in the non-read section NR starting from the transfer request start position TGS. This eliminates the need, that is, the read operation itself is made more efficient. Thereby, faster data transfer to the host computer can be realized. In particular, this processing is very suitable for a reproducing apparatus having a high error correction capability.

By the way, in some cases, even if the latter half reading operation is executed, there is a case where the data cannot be completely recovered in the non-reading section NR by the error correction. In that case, the processing is step F
From 207, the process proceeds to F208. As shown in the operation example of FIG. 10, after the end of the read operation RD3 as the second half read operation,
The track jump TJ5 is executed on the inner circumference side. Note that the execution condition of the second half read operation in the second embodiment is that the data length requested to be transferred is within one track, as in the second half prefetch operation in the first embodiment. Does not need to be asked (that is, the second half read operation of this example is effective even for a transfer request of a data section exceeding one track, and the processing can be speeded up). However, even if the track jump TJ5 is performed only on the inner circumference side, the track jump TJ5 is not always located before the transfer request start position TGS. That is, this track jump TJ5 is a track jump of one track in the example of FIG. 10, but in order to move to a point before the transfer request start position TGS, it is necessary to make a track jump to the inner circumference side by a plurality of tracks. Sometimes it becomes. Transfer request start position TGS by track jump TJ5
When the laser spot is moved to a point just before this, as shown as read standby W, it waits until the laser spot reaches the transfer request start position TGS. Then, when the transfer request start position TGS is reached, the process proceeds from steps F209 to F209.
Proceeding to 210, an operation RD4 of reading data from the transfer request start position TGS is performed.

This read operation RD4 is performed up to the position immediately before the start of data read by read operation RD3.
That is, the read operation is performed until all data in the range from the transfer request start position TGS to the transfer request end position TGE can be accumulated in the data buffer 20. As the read operation RD2 in step F210, the read operation RD3
Then, the data reading in the range where the reading has not been performed is performed, and when the reading of all the data in the requested range is completed, the process proceeds from step F211 to F212, and the requested data stored in the data buffer 20 at that time is stored. The data in the data range will be transferred to the host computer.

In the case where the processing by the second half reading operation cannot be properly realized as described above, the reading in the range defined as the non-reading section is performed in the second half reading operation, that is, the first embodiment. A read operation similar to the latter half pre-read operation is performed. Therefore, even if the NR data cannot be restored in the non-reading section due to the error correction, the transfer operation itself based on the read command does not become impossible.

By the way, due to the positional relationship between the seek landing point SE, the transfer request start position TGS, the transfer request end position TGE, and the error correction capability, even if the latter half read operation is executed in step F203, the data in the non-read section due to error correction is obtained. If it is determined that the restoration cannot be performed, it is better not to execute the second half reading operation. For example, FIG.
Tentatively performs a track jump to the outer periphery of one track as indicated by a wavy arrow, and from there the transfer request end position TGE
Even if the latter half of the requested data range is read, for example, the non-read section is longer, and the read data alone cannot correct the data in the non-read section by correction. Is shown.

In such a case, the process proceeds from step F203 to F209, and waits for the transfer request start position TGS in the read standby state W as shown in FIG. Then, when the laser spot reaches the transfer request start position TGS, the process proceeds to step F210, and performs an operation RD9 of reading data from the transfer request start position TGS. In this case, when the reading to the transfer request end position TGE is completed, it is determined in step F211 that the reading of all requested data has been completed, and the process proceeds to step F212, in which the request stored in the data buffer 20 is stored. The data in the data range is transferred to the host computer.

As described above, in this example, when the condition is satisfied according to the determination in step F203, the latter half reading operation is performed, whereby the data reproduction operation and the transfer process can be speeded up. If the effect of the read operation cannot be expected, the appropriate read operation is performed by not performing the second half read operation, and an optimal operation according to the situation is realized.

Even if a negative result is obtained in step F203, the process proceeds to step F204 after judging other conditions such as the data length requested to be transferred is within one track. Is also good. In this case, a result indicating that the data cannot be repaired by the error correction will be obtained in step F207, but in this case, the data transfer is properly executed since the data is read from the transfer request start position TGS as described above. You can do it.

<Third Embodiment> FIG. 11 shows a process when a read command is issued from a host computer in a disk reproducing apparatus according to a third embodiment.
This will be described with reference to FIG. The example of the third embodiment is characterized by the latter half prefetching operation as in the first embodiment, but extends the seek target range before executing the reading. 11 shows a control process of the system controller 10 when a read command is generated, FIG. 12 shows a seek target range in this example, and FIG. 13 shows a track on a track TK of the disk 90 realized by the control of the system controller 10. It is a diagram schematically showing the operation.

When a read command is generated, the process of the system controller 10 proceeds to step F301 in FIG. 11, and firstly executes a seek operation for the specified request data range (the first address and data length to be read) together with the read command. . However, in this case, unlike the first and second embodiments, the seek target targets the transfer request start position, and extends from the transfer request start position to a range of one track before and one track after. Range. That is, as shown in FIG. 12, the range of two tracks around the transfer request start position TGS is set as the seek target range.

By setting such a seek target to the servo processor 14 as a seek operation and issuing an instruction, the movement of the pickup 1 by the sled mechanism 8 and the biaxial mechanism 3
, The position of the laser spot is one track before the transfer request end position TGS, or the transfer request end position TGS.
Is moved to the range one track behind.

Here, when the seek landing point SE is in a range one track before the transfer request end position TGS, the same processing as in the first embodiment will be performed thereafter. That is, the process proceeds from step F302 to step F103 in FIG. The operation in this case is the same as that of the first embodiment, and the description is omitted.

The seek landing point SE is the transfer request end position TG
If the range is one track behind S, the process proceeds from step F303 to F304. Then, it is determined whether or not the data length from the transfer request start position TGS to the transfer request end position TGE as the data range requested to be transferred in step F304 is within the range of one track orbit. In step F305, it is determined whether or not an effective second-half prefetch operation can be realized by performing a necessary track jump when performing the second-half prefetch operation. However,
When proceeding to step F304, the seek landing point SE
Is beyond the transfer request end position TGS (that is, since the seek landing point is already in the middle of the read range requested to be transferred), the required track jump is performed only once for jump back. .

Although the processing of FIG. 11 is not shown, in some cases, the seek landing point SE is in a range from the transfer request end position TGS to one track behind, but the seek landing point SE is the transfer request point SE. It is also conceivable that the end position TGE has been exceeded. In such a case, a track jump is performed to a range one track before the transfer request end position TGS, and then a track jump is performed.
The process may proceed to step F103.

If an affirmative result is obtained as the determination in steps F304 and F305, the process proceeds to step F306 to execute the latter half prefetching operation. That is, as shown in FIG. 13, since the seek landing point SE is located in the middle of the data range to be read, the reading operation RD5 of data from the seek landing point SE is started as step F306. The read data is subjected to decoding, error correction processing, and the like, and is accumulated in the data buffer 20.

Transfer request end position T as read operation RD5
Upon completion of the reading up to the GE, the process proceeds to Step F307
Then, the process proceeds to F308 to execute a track jump TJ6 toward the inner peripheral side as shown in FIG. Then, the position of the track jump destination is a point before the transfer request start position TGS, and therefore, as shown as read standby W, it waits until the laser spot reaches the transfer request start position TGS. Then, when the transfer request start position TGS is reached, the process proceeds from step F309 to F310 to perform an operation RD6 of reading data from the transfer request start position TGS. The read data is subjected to decoding, error correction processing, and the like, and is accumulated in the data buffer 20.

The read operation RD6 is performed up to the position immediately before the start of the data read by the read operation RD5.
That is, the read operation is performed until all data in the range from the transfer request start position TGS to the transfer request end position TGE can be accumulated in the data buffer 20. As described above, as read operation RD6 in step F310, data read is performed in a range where data was not read in read operation RD1, and when reading of all data in the requested range is completed, the process proceeds from step F311 to F312. At that time, the data in the requested data range stored in the data buffer 20 is transferred to the host computer.

That is, when the seek landing point is already in the middle of the data range to be read, by performing the latter half prefetching operation from that position, it is possible to eliminate waste of disk rotation waiting time and to seek. Since the target is also widened, there is a high possibility that the seek operation can be completed more quickly. Therefore, faster data transfer to the host computer can be realized.

When a negative result is obtained in step F304 or F305, the second half prefetch operation is performed similarly to the case where a negative result is obtained in step F103 or F104 in FIG. 2 of the first embodiment. In this case, the disk rotation waiting time cannot be effectively canceled.
08, the transfer request start position TGS
When the laser spot reaches the transfer request start position TGS, the transfer request start position TGS is changed to the transfer request end position TGS in the processing after step F310.
It reads out data up to GE and transfers data to the host computer. That is, when the effect of the second half prefetch operation cannot be expected, the appropriate read operation is executed by not executing the second half prefetch operation.

<Fourth Embodiment> FIG. 1 shows a process when a read command is issued from a host computer in a disk reproducing apparatus according to a fourth embodiment.
4 and FIG. The example of the fourth embodiment is as follows.
Although the second embodiment is characterized by the second half read operation as in the second embodiment, the seek target range before the execution of the read operation is expanded similarly to the third embodiment. FIG. 14 shows the system controller 1 when a read command is generated.
0, and FIG.
0 of the disk 90 realized by the control of
The operation on K is schematically shown.

When a read command is generated, the processing of the system controller 10 proceeds to step F401 in FIG. 14, and firstly executes a seek operation for the specified request data range (the head address and data length to be read) together with the read command. . In this case, as in the third embodiment, the seek target is set to a transfer request start position as a target, and the seek target is set to a position immediately before the transfer request start position.
The range for the track and the range up to one track later.
That is, the range for two tracks centered on the transfer request start position TGS shown in FIG. 12 is set as the seek target range.

By setting such a seek target to the servo processor 14 as a seek operation and issuing an instruction, the movement of the pickup 1 by the sled mechanism 8 and the biaxial mechanism 3
, The position of the laser spot is one track before the transfer request end position TGS, or the transfer request end position TGS.
Is moved to the range one track behind.

Here, when the seek landing point SE is in a range one track before the transfer request end position TGS, the same processing as in the second embodiment is performed thereafter. That is, the process proceeds from step F402 to step F203 in FIG. The operation in this case is the same as that of the second embodiment, and the description is omitted.

The seek landing point SE is the transfer request end position TG
If the range is one track behind S, the process proceeds from step F403 to F404. Then, in step F404, it is determined whether or not data in a section that has not been read can be restored by an error correction process using data read as the second half read operation. That is, the determination process is the same as that in step F203 of FIG.

Although the processing in FIG. 14 is not shown, in some cases, the seek landing point SE is within a range of one track after the transfer request end position TGS, but the seek landing point SE is not It is also conceivable that the end position TGE has been exceeded. In such a case, after performing a track jump to a range that is one track before the transfer request end position TGS, FIG.
Step F203 may be performed.

If an affirmative result is obtained in step F404, the flow advances to step F405 to execute the latter half prefetching operation. That is, as shown in FIG. 15, since the seek landing point SE is located in the middle of the data range to be read, the reading operation RD6 of data from the seek landing point SE is started as step F305. The read data is accumulated in the data buffer 20 while performing decoding, error correction processing, and the like.

Transfer request end position T as read operation RD6
Upon completion of the reading up to the GE, the processing proceeds to step F406
Then, the process proceeds to F407 to determine an error correction result. That is, when the read operation RD6 is completed, even the data in the non-read section NR where no reading is actually performed can be restored by the error correction processing of the read data in that section, and all the necessary data to be transferred can be obtained. It is determined whether or not it has been performed. If all data has been obtained by the error correction processing, the process proceeds from step F407 to F412, and all data in the requested data range stored in the data buffer 20 at that time is transferred to the host computer.

That is, when the seek landing point is already in the middle of the data range to be read, by performing the latter half reading operation from that position, the waste of disk rotation waiting time can be eliminated, and the seek can be realized. Since the target is also widened, there is a high possibility that the seek operation can be completed more quickly. Therefore, faster data transfer to the host computer can be realized.

If it is determined in step F407 that the data cannot be completely restored in the non-read section NR due to the error correction, the process proceeds from step F407 to F408, and the position after the end of the read operation RD6 as the second half read operation. Thereafter, a one-track jump (or a few-track jump) is performed on the inner circumference side to move the laser spot to a point before the transfer request start position TGS. Then, when the transfer request start position TGS is reached, in a process after step F410, a data read operation from the transfer request start position TGS in a section that has not been read yet is performed. When all the data in the range from the transfer request start position TGS to the transfer request end position TGE has been accumulated in the data buffer 20, the data is transferred to the host computer.

Further, if a negative result is obtained in step F404, the process proceeds to step F408, in which a track jump is performed on the inner circumference side to move the laser spot to a point before the transfer request start position TGS. Then, when the transfer request start position TGS is reached, the data read operation from the transfer request start position TGS to the transfer request end position TGE is performed in the processing after step F410. When all the data in the range from the transfer request start position TGS to the transfer request end position TGE has been accumulated in the data buffer 20, the data is transferred to the host computer.

As described above, when the error cannot be completely corrected even when the second half read operation is performed, or when the effect of the second half read operation cannot be expected in advance, an appropriate data transfer operation is executed by reading the entire data section. .

Even if a negative result is obtained in step F404, the process may proceed to step F405 after judging other conditions such as the data length requested for transfer is within one track. Good. In this case, a result indicating that the data cannot be repaired by the error correction will be obtained in step F407, but in this case, the data transfer is properly executed since the data is read from the transfer request start position TGS as described above. You can do it.

Although the embodiment has been described above, various modifications of the configuration and operation of the reproducing apparatus are conceivable as the present invention. The operation may be such that a period that has conventionally been waiting for disk rotation can be effectively used as a reading operation period. Further, although the description has been given of the example of the disk in which the track progresses spirally from the inner circumference to the outer circumference, the present invention is also applicable to a reproducing apparatus corresponding to a disk in which the track progresses spirally from the outer circumference to the inner circumference. For example, the seek target range and the track jump direction in the operation of each of the above embodiments may be applied to the inner and outer peripheries in reverse.

[0074]

As described above, according to the present invention, when a specific condition is satisfied in response to a data request in which a read section is designated, the first section from the middle position of the read section to the end position is read. A read operation is performed first, followed by a second read operation from the start position of the read section to an intermediate position, and a second half read operation is performed, and data read by the second half read operation is accumulated. Later, to output as data from the start position to the end position of the read section,
A part of the section requested to be read can be read during the disk rotation waiting period, that is, the disk rotation waiting period can be eliminated and efficient processing can be performed. This has the effect that data reproduction and output (for example, data transfer to the host computer) can be performed very quickly.

Specific conditions for executing the second half prefetch operation include that the read section is a section within one round track, and that even if a track jump required for the second half prefetch operation is performed, First in operation
It is determined that the period from the start of the read operation to the end of the second read operation can be completed within a period of one rotation of the disk, whereby the efficiency of the second half preread operation can be most appropriately executed. is there.

In response to a data request, a seek operation is executed for the range from the start position of the read section to one turn before the track, and then a second half prefetch operation is executed if a specific condition is satisfied. This makes it possible to appropriately execute the second half prefetch operation. Furthermore, if the seek operation is performed for the purpose of making a single round of the track before and after the start position of the read section, the target range of the seek operation is widened, and the possibility that the seek operation can be completed quickly is increased. This can contribute to speeding up of data reproduction output.

Further, according to the present invention, when a specific condition is satisfied in response to a data request in which a read section is specified, the latter half read operation from the middle position to the end position of the read section is executed. The data from the start position to the end position of the read section is generated by error correction processing of the data read by the latter half read operation, and the data is output. In other words, the section that can be read is read during the conventional disk rotation waiting period, and data of the section that is not read (data from the start position of the read section to the middle position) is generated by error correction processing of the read data. Therefore, there is no need to read all data in the requested section. Therefore, the processing delay due to the disk rotation waiting can be eliminated, and the reading operation itself can be completed in a short time. This has the effect that data reproduction output (data transfer to the host computer) can be performed very quickly.

A specific condition for executing the second half reading operation is that it is determined that data from the start position to the middle position of the reading section can be generated by an error correction process using data read in the second half reading operation. By doing so, there is an effect that the efficiency can be most appropriately performed by the second half reading operation.

If the data from the start position to the middle position of the read section cannot be obtained by the error correction processing, the read operation from the start position to the middle position of the read section is executed to request the data. It is possible to obtain all the data of the section which has not been reproduced, and to prevent a situation that the reproduction cannot be properly executed, and at least a processing delay due to a disk rotation wait can be eliminated.

In response to a data request, a seek operation is performed for the range from the start position of the read section to one turn before the track, and then the latter half read operation is performed if a specific condition is satisfied. Thus, the second half reading operation can be appropriately performed. Furthermore, if the seek operation is performed for the purpose of making a single round of the track before and after the start position of the read section, the target range of the seek operation is widened, and the possibility that the seek operation can be completed quickly is increased. This can contribute to speeding up of data reproduction output.

[Brief description of the drawings]

FIG. 1 is a block diagram of a playback device according to an embodiment of the present invention.

FIG. 2 is a flowchart of processing when a read command is generated according to the first embodiment;

FIG. 3 is an explanatory diagram of a read operation according to the first embodiment.

FIG. 4 is an explanatory diagram of a read operation according to the first embodiment;

FIG. 5 is an explanatory diagram of a read operation according to the first embodiment;

FIG. 6 is an explanatory diagram of a read operation according to a modification of the first embodiment.

FIG. 7 is a flowchart of a process when a read command is generated according to the second embodiment.

FIG. 8 is an explanatory diagram of a read operation according to the second embodiment.

FIG. 9 is an explanatory diagram of a read operation according to the second embodiment.

FIG. 10 is an explanatory diagram of a read operation according to the second embodiment.

FIG. 11 is a flowchart of a process when a read command is generated according to the third embodiment.

FIG. 12 is an explanatory diagram of a seek target range according to the third and fourth embodiments.

FIG. 13 is an explanatory diagram of a read operation according to the third embodiment.

FIG. 14 is a flowchart of a process when a read command is generated according to the fourth embodiment.

FIG. 15 is an explanatory diagram of a read operation according to the fourth embodiment.

FIG. 16 is an explanatory diagram of a spiral track of a disk.

FIG. 17 is an explanatory diagram of a conventional read operation.

[Explanation of symbols]

1 pickup, 2 objective lens, 2 biaxial mechanism, 4
Laser diode, 5 photo detector, 6 spindle motor, 8 thread mechanism, 9 RF amplifier, 1
0 system controller, 13 interface unit, 14 servo processor, 20 data buffer,
90 disk, TGS transfer request start position, TGE
Transfer request end position, SE seek landing point, W read standby, RD1 to RD9 read operation, TJ1 to TJ6 Track jump, NR non-read section

Claims (12)

[Claims] 1. A disk reproducing apparatus for performing a reproducing operation on a disk-shaped recording medium on which a track is formed in a spiral shape, comprising: a data reading means for reading data recorded on the track; Read position control means for controlling the read position of the data read means; data output means for performing predetermined processing on the data read by the data read means and outputting the data; and a read section in response to a specified data request. When a specific condition is satisfied, a first read operation from the middle position to the end position of the read section is performed first, and then a second read operation from the start position of the read section to the middle position is performed. A control is performed so that the data reading means and the reading position control means execute a latter half prefetching operation for performing a reading operation. Reproduction control means for storing, in the data output means, data read by the second half prefetch operation, and then outputting the data as data from a start position to an end position of the read section. Characteristic disk playback device. 2. The disk reproducing apparatus according to claim 1, wherein one of the specific conditions is that the read section is a section within one round track. 3. One of the specific conditions is that, even if a track jump required for the latter half prefetch operation is performed, the second read operation starts from the start of the first read operation in the latter half prefetch operation. 2. The disc reproducing apparatus according to claim 1, wherein it is determined that the end of the disc can be completed within one rotation of the disc. 4. The read control unit according to a data request in which a read section is specified, wherein the read position control unit sends the data read unit to the read position control unit for a range from a start position of the read section to one track before one round. 2. The disk reproducing apparatus according to claim 1, wherein, after performing the seek operation, if the specific condition is satisfied, the second half prefetch operation is performed. 5. The read control section, in response to a data request in which a read section is designated, performs the data read operation to the read position control section for a range of one round of each track before and after the start position of the read section. 2. The disc reproducing apparatus according to claim 1, wherein, after the seek operation of the means is executed, the second half prefetch operation is executed when the specific condition is satisfied. 6. A disk reproducing apparatus for performing a reproducing operation on a disk-shaped recording medium having tracks formed in a spiral shape, wherein: data reading means for reading data recorded on the tracks; Read position control means for controlling the read position of the data read means, data output means for performing predetermined processing on the data read by the data read means, and outputting the data, and in response to a data request in which a read section is specified. When a specific condition is satisfied, control is performed so that the data reading unit and the reading position control unit execute a second half reading operation from the middle position to the end position of the reading section. And causing the data output means to execute an error correction process on the data read by the read operation. Reproduction control means for causing the data output means to output data from the start position to the end position of the read section in response to data from the start position to the end position of the read section being obtained in the normal processing; and A disk playback device comprising: 7. The specific condition is that the error correction process using data read in the second half read operation determines that data from the start position of the read section to the middle position can be generated. 7. The disk reproducing apparatus according to claim 6, wherein: 8. When the error correction process does not obtain data from the start position of the read section to the intermediate position, a read operation from the start position of the read section to the intermediate position is performed. 7. The data from the start position to the end position of the reading section is obtained by executing the data reading, and the data output unit outputs the data from the start position to the end position of the reading section.
A disk playback device according to claim 1. 9. The read control section, wherein the read control section controls the read position control section in response to a data request in which the read section is specified, for a range from a start position of the read section to one track before the track. 7. The disc reproducing apparatus according to claim 6, wherein, after the seek operation is performed, when the specific condition is satisfied, the second-half read operation is performed. 10. The reproduction control means, wherein, in response to a data request in which a read section is designated, the read position control means performs the data read operation for a range of one turn of each track before and after the start position of the read section. 7. The disk reproducing apparatus according to claim 6, wherein after performing the seek operation of the means, if the specific condition is satisfied, the second-half reading operation is performed. 11. A data reproducing method for a disk-shaped recording medium having tracks formed in a spiral form, wherein a read section is in a range from a start position of the read section to one turn before the track in response to a designated data request, or A seek operation aimed at a range of each track around the track before and after the start position of the read section; and an end point of the seek operation, or a read operation of the read section as a point where a track jump is performed from the end point of the seek operation. A first read operation for reading from a middle position to the end position of the read section; a second read operation for reading from a start position of the read section to the middle position; and the first and second read operations Output operation for generating and outputting reproduction data from the start position to the end position of the read section based on the data read by the read operation of Data reproduction method characterized by the, execution. 12. A data reproducing method for a disk-shaped recording medium having tracks formed in a spiral form, wherein a read section is in a range from a start position of the read section to one turn before the track in response to a designated data request, or A seek operation aimed at a range of each track around the track before and after the start position of the read section; and an end point of the seek operation, or a read operation of the read section as a point where a track jump is performed from the end point of the seek operation. A read operation for reading data from an intermediate position to the end position of the read section and an error correcting operation of data read by the read operation generate reproduced data from a start position to an end position of the read section. A data reproducing method, comprising: performing an output operation of outputting a data by performing the following.