JPH11154374A - Reproducing device, and cache processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase output speed of transfer. SOLUTION: A reproducing device performs seek operation when seek from a host computer is instructed, while performs buffering for a cache memory of continuous data from a finish position of seek operation (F103). After that, when transfer of data read out from a seek finish position is required, buffered data may be transferred (F109).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reproducing apparatus capable of performing a reproducing operation corresponding to a recording medium such as an optical disk and a cache processing thereof.

[0002]

2. Description of the Related Art As an optical disk recording medium, so-called C
CD-type discs such as D-ROM and DVD (Digital Versatile Disc / Di) suitable for multimedia applications
gitalVideo Disc) has been developed. In playback devices corresponding to these optical discs,
Data is read out by irradiating a track on the disk with laser light and detecting the reflected light.

[0003] Such a reproducing apparatus performs a disk reproducing operation in response to a command (data transfer request) from a host computer, for example, and performs an operation of transmitting reproduced data to the host computer. It is required that data be transferred quickly in response to a read command. The read command includes command 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.

When a read command is issued, the reproducing apparatus basically performs a seek (access) operation of the optical head and reads data in order to read the requested data. Then, the read data is transferred to the host computer. In such a reproducing apparatus, a so-called cache memory is mounted, and data is output through the cache memory.

That is, the reproducing apparatus reads the data of the data sector requested by the host computer from the disk and stores (buffers) the data in the cache memory.
The data is transferred from the cache memory to the host computer, and the data of the sector following the requested data sector is also read and stored in the cache memory. This is a so-called prefetch operation. Then, when the next data request is made from the host computer, if the requested data is stored in the cache memory (if there is a cache hit),
Data transfer to the host computer can be performed without performing disk access, that is, apparently access time can be reduced. That is, when data requests for successive sectors are continuously issued from the host computer (so-called sequential read), the prefetch operation to the cache memory is a very effective method in terms of quick data transfer.

Some types of host computers issue a seek instruction and a data transfer request as separate commands. For example, ATAPI, SCS
Such a form is seen in the system of the I system. In this case, the host computer first issues a seek command to a certain target position on the disc, and in response to this, the reproducing device executes a seek operation to the designated target position. Thereafter, the host computer issues a transfer request for specific data as a read command, and in response to this, the playback device executes data reading from the disk, decoding / buffering, and transfer to the host computer. Of course, if there is a cache hit when the read command is generated, the reproducing device transfers the data stored in the cache memory.

[0007]

SUMMARY OF THE INVENTION For example,
In a system in which a host computer and a playback device are connected, it is required that the playback device quickly perform data transfer in response to a transfer request from the host computer. Since such speediness directly affects, for example, the execution start time of an application, speeding up transfer is regarded as important. Processing operations that require time for transfer in the reproducing apparatus include a seek operation to a target position, a data read operation, a decoding process, an error correction process, and buffering. If the above cache hit transfer is possible, these operations can be omitted, which can contribute to speeding up. However, if cache hit transfer is not possible, of course, speeding up of transfer is not achieved.

[0008]

SUMMARY OF THE INVENTION In consideration of such circumstances, the present invention provides a system in which a seek command (seek instruction) and a read command (data transfer request) are generated at different times as described above. It is an object of the present invention to speed up transfer by enabling cache hit transfer in most cases when a read command occurs.

For this reason, in the reproducing apparatus, when a seek instruction without a data request is issued, the control means causes the read means to perform a seek operation and stores continuous data from the seek operation completion position in the cache memory means. So that the data storage operation is performed
The reading means and the cache memory means can be controlled. In other words, when a seek instruction is issued, it can be predicted that there is a transfer request for data read from the seek completion position after that, so that data is buffered before a data transfer request is issued. In most cases, the data request after the seek instruction is for the data from the seek destination, that is, the buffered data, so when a command as a data request is issued, a cache hit transfer is performed. You can transfer it.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A reproducing apparatus using an optical disk as a recording medium will be described below as an embodiment of the present invention.
The optical disc loaded in the reproducing apparatus of this example is, for example, C
A CD-type disc such as a D-ROM, a DVD, and the like can be considered. Of course, the present invention can be applied to a disc reproducing apparatus corresponding to other types of optical discs.

FIG. 1 is a block diagram of a main part of a reproducing apparatus 70 of the present embodiment. The disk 90 is loaded on the turntable 7, and is rotated 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 M decoding, MPEG decoding and the like.

The decoder 12 accumulates the data subjected to the EFM demodulation in a cache memory 20 as a data buffer, and performs error correction processing and the like on the cache memory 20. Then, the buffering to the cache memory 20 is completed in a state where the error is corrected and the reproduced data is proper. As the playback output from the playback device 70, the data buffered in the cache memory 20 is read and transferred and output.

The interface section 13 is connected to an external host computer 80, and is connected to the host computer 80.
The communication of the reproduction data and various commands is performed between them. That is, the reproduction data stored in the cache memory 20 is transferred and output to the host computer 80 via the interface unit 13. Further, a seek command, a read command, and other command signals from the host computer 80 are supplied to the system controller 10 via the interface unit 13.

The servo processor 14 detects various focus, tracking, thread, 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, 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.
Then, the system controller 10 executes various processes in response to a command from the host computer 80. For example, when requesting the reproducing device 70 to transfer certain data recorded on the disk 90, the host computer 80 first issues a seek command to instruct the seek operation of the pickup 1 to a certain target position on the disk 90. After that, a transfer of data at a specific address is requested as a read command.

From the viewpoint of the system controller 10, the series of reproduction operation control first includes the host computer 8.
In response to a seek command from 0, seek operation control is performed for the designated address. That is, a command is issued to the servo processor 14 to execute the access operation of the pickup 1 targeting the address specified by the seek command. Then, the host computer 80
When a read command is supplied from the host computer 80, operation control necessary for transferring data in the designated data section to the host computer 80 is performed. That is, the cache memory 2
0, the cache hit transfer is performed, or if the cache hit transfer cannot be performed, data reading / decoding / buffering from the disk 90 is performed.
Get the requested data and transfer it.

A read command from the host computer 80, that is, a transfer request, includes a request start address which is the first address of a requested data section, a request data length (data length) as a section length from the first address. Become. For example, request start address =
A transfer request of N, request data length = 3 is LBA "N"
LBA “N + 2” means a data transfer request of three sectors. LBA is a logical block address (LOGICAL BL
OCK ADDRESS), which is an address given to the data sector of the disk 90.

Basically, the system controller 10 performs the processing for the transfer described above.
As processing after the seek command, data reading / buffering from the disk 90 is performed before a read command occurs. Such processing of the system controller 10 of the present example will be described with reference to the flowchart of FIG.

FIG. 2 shows the processing of the system controller 10 after the generation of the seek command from the host computer 80. When the seek command is generated, the processing proceeds from step F101 to F102, and the seek operation is executed. That is, the movement of the pickup 1 to the address specified as the seek command is executed by thread control and tracking control by the servo processor 14.

When the seek operation is completed, step F10
Proceeding to 3, the buffering operation necessary for ensuring that continuous data from the address of the seek completion point is secured in the cache memory 20 is started. That is, the disk read operation is executed at the time when the read command has not been generated. Examples of necessary buffering operations are shown in FIGS. 3 and FIG. 4, area # 0
To # 6 indicate storage areas in the cache memory 20.

FIG. 3A shows a case where the cache memory 20 is in an initial state, for example, when a seek command is generated, that is, a state where valid data is not stored. At this time, it is assumed that a seek command in which LBA “M” is specified as a seek target address is supplied. At this time, the data of LBA “M” does not exist in the cache memory 20. Therefore, step F103
The buffering operation required to ensure that continuous data from the address of the seek completion point LBA “M” in the cache memory 20 is secured in the cache memory 20 is LB
The operation is to read the continuous data after A "M" from the disk 90, perform decoding and error correction processing, and store the data in the cache memory 20. By this operation, for example, as shown in FIG.
Buffering of sectors starting with "M" will be performed.
Although FIG. 3A shows the initial state, even if some data is buffered in the cache memory 20, if the data as the LBA “M” of the seek target address is not buffered, the data is After invalidating the data stored up to
As shown in (b), the buffering of the sector after the LBA "M" is performed.

On the other hand, FIG.
2 shows a state in which data of LBA “M−2” to LBA “M + 1” is buffered, for example. In such a state, L as an address for seek
It is assumed that a seek command specifying BA “M” has been supplied. In this case, the buffering operations required to secure continuous data from the address of the seek completion point LBA “M” in the cache memory 20 in step F103 include LBA “M” and LBA “M +
Since the data “1” has already been buffered in the cache memory 20, continuous data after the LBA “M + 2” is read from the disk 90, decoded and error-corrected, and stored in the cache memory 20. . Therefore, as shown in FIG. 4B, for example, buffering after LBA "M + 2" is performed to secure continuous data after LBA "M" as a seek completion point.

In step F103, as in the examples of FIGS. 3 and 4, buffering for securing continuous data after the seek target address is started. Thereafter, the system controller 10 executes this buffering while executing this buffering. The processing from step F104 is performed. First, step F10
In steps F4 and F105, a read command and a seek command from the host computer 80 are monitored. In addition to the read command and the seek command, there are various commands issued from the host computer 80, and the system controller 10 also performs predetermined corresponding processing on these commands. The illustration and description in 2 are omitted. When the read command and the seek command are not supplied, the buffering started in step F103 is continued. In this case, whether the buffering amount of the cache memory 20 has reached the full capacity in step F106 is determined. Is monitored, and if the capacity becomes full, the buffering operation is stopped in step F107.

Normally, a read command is generated at a certain point after the seek command is generated, and is supplied to the system controller 10. In this case, the process proceeds from step F104 to F108. Then, in response to the read command, the system controller 10 first checks whether or not the data specified by the read command has a cache hit.

If there is a cache hit, the process proceeds to step F109, where data of one or a plurality of sectors requested by the read command is read from the cache memory 20 and transferred by the cache hit. Then, the process returns to the loop of steps F104, F105, and F106, and waits for the next command and continues buffering until the cache memory 20 becomes full.

On the other hand, if it is determined in step F108 that there is no cache hit, the process proceeds to step F110 to stop the buffering that has been continued at that time (of course, at this point, the cache memory 20 is already full). If buffering is stopped due to capacity, stop processing is unnecessary). Then, the data buffered at that time is invalidated. Then, in step F111, a new buffering operation, that is, reading from the disk 90, decoding, error correction, and storage in the cache memory 20 is started from the first data requested to be transferred as the read command. Also,
If one or a plurality of data requested by the read command can be stored in the cache memory 20 by this buffering, the data is transferred to the host computer 80. Thereafter, the process returns to the loop of steps F104, F105, and F106, and waits for the next command.
The buffering started at 11 is transferred to the cache memory 20.
Continue until is full.

When a read command is issued as in the processing of FIG.
Although the processing of steps 110 and F111 is performed, in the case of the present example, it is determined in most cases that a cache hit has occurred in the determination processing of step F108 due to the buffering operation started from step F103. Will be. That is, in most cases, step F109
It becomes the processing of.

Normally, the host computer 80 issues a seek command as a subsequent read command, targeting the position of the first address among the addresses for which a transfer request is made. Therefore, as shown in the examples of FIGS. 3 and 4, when the immediately preceding seek command targets the LBA “M”, then, for example, a read command requesting data after the LBA “M” Will be issued. For example, as shown in FIG. 3 and FIG. 4, after issuing a seek command targeting LBA “M”, a read command of request start address = M and request data length = 1, that is, data transfer of one sector of LBA “M” Assuming that the request is issued, in both cases of FIG. 3 and FIG.
Since "M" has a cache hit, the process proceeds from step F108 to F109 to perform cache hit transfer. That is, data transfer can be performed without performing reading, decoding, error correction, and the like for the read command.

Further, assuming that a request start address = M + 1 and a requested data length = 2, that is, a data transfer request of two sectors of LBA "M + 1" and LBA "M + 2" are issued again as a read command, FIG. , LBA “M + 1”, LB
Since A "M + 2" has a cache hit, the process also proceeds from step F108 to F109 in this case.
A cache hit transfer will be performed. That is, data transfer can be performed without performing read, decode, error correction, and the like even for a read command.

As described above, by executing the buffering from the point where the seek is performed in response to the seek command, the read command can be almost always handled by the cache hit transfer when the read command is generated. The average transfer processing speed for a command can be greatly increased. Also, after the seek command and before the read command is issued, the same seek command is often issued again, or another type of command such as status confirmation is often issued. As a result, there is more time to advance buffering, and the effect as prefetching buffering,
That is, the probability of the cache hit transfer is large.

After a certain seek command, in a loop of steps F104, F105, and F106, one or more subsequent read commands are waited and buffering is continued until the cache memory 20 becomes full. However, when a new seek command is issued, the process returns from step F105 to F102, performs a seek operation and performs buffering as step F103, and waits for a subsequent read command in a loop of steps F104, F105, and F106. Will be.

Although the example of the embodiment has been described above, the configuration and the processing procedure of the reproducing apparatus according to the present invention are not limited to the above example, and various modified examples can be considered. In any case, in response to the seek command from the host computer 80, the reproducing device 70 may buffer the data that will be requested thereafter in advance.

[0039]

As described above, according to the present invention, when a seek instruction without a data request is issued, a seek operation of the read means is executed, and continuous data from the seek operation completion position is stored in the cache memory means. Perform buffering to be stored in. That is, when a seek instruction is issued, it is predicted that there is a transfer request for data read from the seek completion position thereafter, and the data is buffered before the data transfer request is issued. Therefore, when a data request is issued thereafter, in most cases, the data can be transferred and output by the cache hit transfer, that is, there are many opportunities for performing a very quick transfer. As a result, on average, the apparent access time as a reproducing apparatus is remarkably shortened, and a high performance can be realized as a system including the host computer and the reproducing apparatus. Furthermore, in order to realize such processing of the present invention, it is only necessary to devise firmware of a so-called reproducing apparatus, and there is an advantage that there is no need to change the hardware configuration.

[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 a process of the playback device of the embodiment.

FIG. 3 is an explanatory diagram of a buffering operation of the playback device of the embodiment.

FIG. 4 is an explanatory diagram of a buffering operation of the playback device of the embodiment.

[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 cache memory, 70 playback device, 80 host computer, 90
disk,

Claims (2)

[Claims] 1. A reading means capable of reading data from a recording medium, a cache memory means for storing data read by the reading means, and the reading means and / or the cache memory in response to a seek instruction or a data request. Control the operation of the means,
Control means for executing an instructed seek operation or transfer output of requested data, wherein the control means executes a seek operation of the read means when a seek instruction not accompanied by a data request is issued. And a control unit that controls the read unit and the cache memory unit so that a data storage operation is performed so that continuous data from the seek operation completion position is stored in the cache memory unit. 2. A cache processing method in a reproducing apparatus that operates in response to a command from a host device, wherein when a command as a seek instruction without a data request is supplied from a host device, a seek operation according to the seek instruction is performed. After executing the operation, read data from the recording medium and store the read data in the cache memory so that continuous data after the seek completion position on the recording medium is held in the cache memory. And a cache processing method.