JPH11259239A - Optical disk reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical disk reproducing device for operating efficient data transfer by saving the waste of the reproduction of the overlapped part of data from a CD-ROM by using the overlapped part of data at the time of the data storage, transfer, and abandonment of a buffer memory. SOLUTION: The overlapped part and overlapped amount of data stored in a buffer RAM and data to be stored in the buffer RAM the next are detected (S12), and the overlapped part is left in the buffer memory (S15-S17), and the other part except for the overlapped part is abandoned from the buffer memory. Therefore, the waste of the reproduction of the overlapped part from a CD-ROM again can be saved, and a time required for storing data can be shortened (S18). Thus, efficient data transfer can be attained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical disk reproducing apparatus, and more particularly to an optical disk reproducing apparatus having a buffer memory for storing reproduced data.

[0002]

2. Description of the Related Art CDs (Compact Disks) are widely used for reproducing music, and CD-ROMs using the CDs as a read-only data recording medium are receiving attention. In order to increase the data transfer speed, an optical disk reproducing device, which is a drive device for a CD-ROM, is currently being called a CD-ROM drive which is called a several to several tens times speed drive.
Drive devices (hereinafter referred to as CD-ROM devices) are the mainstream.

Here, the speed of several to several tens of times means that the rotation speed of a disk (CD-ROM) by a disk rotation mechanism is the disk rotation speed (1.2 to 1.4 m / s) of a CD player for audio reproduction. ) Means that the rotation speed is several to several tens times each. In general, the data transfer rate can be increased by increasing the rotation speed of the disk.

With the increase in data transfer speed, CD-R
The OM device has a buffer memory in the device, reads data requested to be transferred from the host computer from the disk, stores the data in the buffer memory, and transfers the data from the buffer memory to the host computer. After transferring data to the host computer, the buffer memory
By making the storage part of the transferred data writable, the data is discarded to secure an empty area.

In general, a buffer memory mounted on a CD-ROM device is controlled via a RAM controller by a control circuit supplied with a transfer request from a host computer. The control of the buffer memory executed by the control circuit has executed the command transmitted from the host computer as it is.

[0006]

A buffer memory mounted on a CD-ROM device is controlled via a RAM controller by a control circuit supplied with a transfer request from a host computer. At this time, the control of the buffer memory by the control circuit executes the command transmitted from the host computer as it is.

FIG. 6 is a diagram showing a processing procedure of the buffer memory. The buffer memory stores data supplied from the signal processing circuit shown in FIG. 6A in response to a transfer request from the host computer.
The data stored in the buffer memory shown in (B) is transferred to the host computer. The buffer memory is
The transfer of the data to the host computer is completed, and immediately thereafter, the data stored in the buffer memory is discarded as shown in FIG.

After that, the buffer memory stores the data supplied from the signal processing circuit shown in FIG. 6D in response to the next transfer request from the host computer. Immediately thereafter, the buffer memory shown in FIG. Transfer the data stored in the memory to the host computer. The buffer memory finishes transferring data to the host computer,
Immediately thereafter, the data stored in the buffer memory is discarded as shown in FIG.

For example, as shown in FIGS. 6B and 6E, even when the data stored in the buffer memory includes overlapping portions (overlapping portions) 42 and 43, the buffer memory is All stored data is transferred to the host computer and then discarded, and data that partially overlaps the discarded data is read again.

In particular, when music data is transferred as data from the buffer memory to the host computer, there is a case where continuously overlapping data is read out for the purpose of preventing skipping or the like. In this case, if the command transmitted from the host computer is executed as it is, there is a problem that the useless operation is repeated as described above, resulting in poor efficiency.

Further, the CD-ROM device performs a read-ahead process for reading out the data requested to be transferred and storing the data in the buffer memory, and storing the data to be reproduced continuously until the buffer memory becomes full. However, in a disk in which dummy data is recorded every predetermined number of data blocks, a series of commands requesting data separated at predetermined data intervals may be continuously issued. In this case, useless data such as dummy data that is not used is stored in the buffer memory due to the pre-reading process, so that the capacity of the buffer memory cannot be effectively used, and the bit rate due to the pre-reading is reduced. There is a problem of lowering.

The present invention has been made in view of the above points, and reproduces an overlapped portion of data from a CD-ROM using an overlapped portion of data when storing, transferring, or discarding data in a buffer memory. It is a first object of the present invention to provide an optical disk reproducing apparatus capable of efficiently transferring data without waste, and has a function of storing data in a buffer memory.
It is a second object of the present invention to provide an optical disc reproducing apparatus capable of efficiently utilizing the capacity of a buffer memory and efficiently transferring data by utilizing a gap of pre-read processing data accompanying a transfer request at the time of transfer and discard. The purpose of.

[0013]

Therefore, in order to solve the above-mentioned problems, the present invention according to claim 1 reproduces data from a signal read from an optical disk in response to a transfer request from a host computer. In the optical disc reproducing apparatus for storing the reproduced data in the buffer memory and transferring the data stored in the buffer memory to the host computer, and then discarding the data transferred to the host computer from the buffer memory, the Duplicate data detecting means for detecting an overlapping portion between data already stored in the buffer memory and data to be stored in the buffer memory in response to a current transfer request; and an amount of data corresponding to the overlapping portion in the buffer memory. And the amount of data obtained by subtracting the amount of data corresponding to the overlapping Serial and a data discarding means for discarding from the buffer memory, after the transfer to store the reproduced data from the optical disk according to the present transfer request, by the data discarding means, discards the transferred data.

In this manner, the data amount corresponding to the overlap between the data already stored in the buffer memory by the previous transfer request and the data to be stored in the buffer memory by the current transfer request is left without discarding. By that
It is possible to eliminate the waste of reproducing the duplicated portion of the data from the CD-ROM again, shorten the time required for storing the data, and achieve efficient data transfer.

According to a second aspect of the present invention, in the optical disk reproducing apparatus according to the first aspect, the data amount of the overlapping portion detected last time by the overlapping data detecting means and the data amount detected this time by the overlapping data detecting means. A data discarding amount determining unit that determines the data amount to be discarded by the data discarding unit by comparing the data amount with the data amount of the overlapping portion of the data;

As described above, by determining the amount of data to be discarded by the data discard amount determining means, the data amount of the overlapping portion of data does not change (the data amount of the overlapping portion of data is the same twice). Only in the case where the data discard amount can be updated based on the data amount of the duplicate portion detected by the duplicate data detecting means, the data discard amount can be updated except for a random change in the data discard amount, and efficient data discarding can be performed. The amount can be set, the time required for storing data can be reduced, and efficient data transfer can be performed.

According to a third aspect of the present invention, a signal read out from an optical disk in response to a transfer request from a host computer and a signal read out by a pre-reading process performed in association with the transfer request are composed of data. After reproducing the data, storing the reproduced data in a buffer memory, and transferring data corresponding to a transfer request from the host computer stored in the buffer memory to the host computer,
In an optical disc device for discarding data transferred to the host computer from the buffer memory, a gap data amount detecting unit for detecting a data amount of a gap generated in a pre-read process performed in association with the transfer request; Data discarding means for discarding from the buffer memory a data amount obtained by adding the gap amount to the transferred data.

As described above, the data amount of the gap generated in the prefetching process performed in association with the transfer request is detected,
By discarding the data amount of the gap together with the transfer data after transfer to the host computer, the hit rate by pre-reading is increased, and the useless gap is discarded, and the efficient use of the buffer memory capacity enables efficient data Transfer becomes possible.

According to a fourth aspect of the present invention, a signal read from an optical disk in response to a transfer request from a host computer and a signal read by a pre-read process performed in association with the transfer request include a data After reproducing the data, storing the reproduced data in a buffer memory, and transferring data corresponding to a transfer request from the host computer stored in the buffer memory to the host computer,
In an optical disc device for discarding data transferred to the host computer from the buffer memory, a gap data amount detecting unit for detecting a data amount of a gap generated in a pre-read process performed in association with the transfer request, the gap data amount corresponding to the gap. Data storage prohibiting means for prohibiting storage of data to be stored in the buffer memory.

As described above, the data amount of the gap generated in the pre-reading process performed in association with the transfer request is detected,
By prohibiting the storage of the data corresponding to the gap in the buffer memory, the hit ratio by pre-reading is increased, and efficient data transfer is enabled by effectively utilizing the capacity of the buffer memory. Further, the invention according to claim 1 can be performed together.

According to a fifth aspect of the present invention, in the optical disk reproducing apparatus of the third aspect, the data amount of the gap detected by the gap data amount detecting means at the time of the previous transfer request and the data amount of the gap at the time of the current transfer request. A data discard amount determining means for comparing the data amount of the gap detected by the gap data amount detecting means with the data amount discarded by the data discarding means.

As described above, by determining the data amount of the gap by the pre-read processing to be discarded by the data discarding amount determining means, the data amount of the gap does not change (the data amount of the gap is the same two consecutive times). Only the data discard amount can be updated based on the data amount of the gap detected by the gap data amount detection means, and the data discard amount can be updated except for a random change in the data discard amount, thereby improving the efficient data discard amount. It can be set and efficient data transfer is possible.

According to a sixth aspect of the present invention, in the optical disk reproducing apparatus of the fourth aspect, the data amount of the gap detected by the gap data amount detecting means at the time of the previous transfer request and the data amount of the gap at the time of the current transfer request. A data storage prohibition amount determining unit that compares the data amount of the gap detected by the gap data amount detection unit with the data storage prohibition unit to determine the data amount prohibited from being stored in the buffer memory.

As described above, by determining the data amount of the gap by the pre-reading process in which the data is prohibited by the data storage prohibition amount determining means, the gap data amount detecting means detects the gap data amount only when there is no change in the data amount of the gap. The data storage prohibition amount can be updated based on the data amount of the gap, and the data storage prohibition amount can be updated except for a random change in the data storage prohibition amount. Data transfer becomes possible.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention relating to an optical disk reproducing apparatus will be described below with reference to the drawings. FIG.
1 is a configuration diagram of a CD-ROM device according to an embodiment of the present invention. An optical disk (CD-ROM) 21 is driven by a disk motor 23. The control circuit 28 controls the disk motor 23 and the feed motor of the pickup (optical pickup) 22 via the disk reproduction system control circuit 27 and the servo circuit 26. The laser light emitted from the pickup 22 is reflected on the recording surface of the optical disk 21 and detected by the pickup 22, and is used as a reproduction signal by the amplifier 2.
4 to the RF detection circuit 25. The reproduced signal whose waveform has been shaped by the RF detection circuit 25 is supplied to the servo circuit 2.
6 and the signal processing circuit 29.

The servo circuit 26 performs focus servo and tracking servo of the pickup 22 and servo control of a feed motor of the pickup by using the reproduction signal supplied from the RF detection circuit 25. A control signal for performing CLV servo is supplied. The reproduction signal supplied from the RF detection circuit 25 to the signal processing circuit 29 is subjected to EFM demodulation, and after a block synchronization signal and address data are separated, a buffer R, which is a buffer memory in block units, is generated as reproduction data.
It is written to AM30. The reproduction data read from the buffer RAM 30 is transferred to the host computer.

Writing and reading of reproduction data to and from the buffer RAM 30 are performed under the control of the control circuit 28 using the RAM controller 33. The address data is taken into the RAM 31 via the control circuit 28 and is used for desired data search or the like. Program R
The OM 32 stores a control program executed by the control circuit 28, rotation speed information for each address for CLV control for keeping the disk rotation linear speed of the disk motor 23 constant, and the like.

The buffer RAM 30 is a ring buffer for storing data, and includes, for example, 25 areas and has a storage capacity of 25 blocks. The control circuit 28 holds, as a cache list, information indicating in which area in the buffer RAM 30 the address of the block data in the optical disk 21 is stored.

FIG. 1 is a flow chart of a first embodiment showing a buffer RAM processing procedure in the optical disk reproducing apparatus of the present invention. In step S1, the control circuit 28 receives a command transmitted from the host computer, and in step S2, analyzes the command. In step S3, it is determined whether the command analyzed in step S2 is a read command. If it is determined that the command analyzed in step S2 is a read command, the process proceeds to step S4 to store information such as the read start address and the number of bytes, which are parameters of the read command, and to set the overlap amount in the initial state as a set value. save. If it is determined that the command analyzed in step S2 is not a read command, the process proceeds to step S7.

After step S4, the process proceeds to step S5, where the control circuit 28 controls the disk motor 23 via the disk reproduction system control circuit 27 and the servo circuit 26 in accordance with the parameters of the read command stored in step S4.
And the feed motor of the pickup 22 is controlled. The pickup 22 detects the reproduced signal and supplies the reproduced signal to the signal processing circuit 29 via the amplifier 24 and the RF detection circuit 25.

The signal processing circuit 29 reproduces data from the reproduction signal supplied from the RF detection circuit 25,
Store in AM30. The buffer RAM 30 stores the supplied data, immediately thereafter, transfers the stored data to the host computer, and discards the data by making the stored portion of the transferred data writable. Execute At this time, the buffer RAM 30 discards only the data amount obtained by subtracting the initially set overlap amount from the data transferred to the host computer.

In step S6, the status of the execution result of the read command processing in step S5 is set. In step S7, the system enters an idle state to wait for reception of a read command from the host computer, and proceeds to step S8. In step S8, it is determined whether a read command is received within a predetermined time. If it is determined that the read command has not been received within the predetermined time, the process proceeds to step S9,
The data stored in the buffer RAM 30 and the parameters of the read command are reset, and the process proceeds to step S1. If it is determined that the read command has been received within the predetermined time, the process proceeds to step S11, and a command analysis process for storing information such as a read start address and the number of bytes, which are parameters of the read command, is performed.

In step S12 following step S11, the parameters of the previous read command are compared with the parameters of the current read command, and the data stored in the buffer 30 by the previous read command and the current read command are compared. It is detected whether there is an overlap with the data to be stored in the buffer RAM 30 and whether the overlap amount has changed.

In step S13, it is determined based on the detection result in step S12 whether or not the data has an overlapping portion. If it is determined that the data has an overlapping portion, the process proceeds to step S14. If it is determined that the data does not have an overlapping portion, the process proceeds to step S17. Step S
At 17, the data discard amount of the buffer RAM 30 is updated to an amount obtained by subtracting the initial value of the overlap amount from the data amount of the buffer RAM 30, and the data of the buffer RAM 30 is discarded according to the updated data discard amount.

In step S14, it is determined whether or not the amount of overlap has changed based on the detection result in step S12. If it is determined that there is no change in the amount of overlap, the process proceeds to step S15, and if it is determined that there is a change in the amount of overlap, the process proceeds to step S16. In step S15, the data discard amount of the buffer RAM 30 is updated to an amount obtained by subtracting the overlap amount from the data amount of the buffer RAM 30,
The data in the buffer RAM 30 is discarded according to the updated data discard amount. Here, an upper limit may be set for the overlap amount so that at least a certain amount of memory of the buffer RAM can be secured.

In step S16, the overlap amount is updated and stored, but the data discard amount in the buffer RAM 30 is not updated and the previously set data discard amount is kept.
Here, the past discard amount is similarly maintained even when the overlap amount slightly changes. In a series of commands requesting consecutively overlapped data to improve performance according to the present invention, the overlap amount is uniform, and even if the overlap amount changes even slightly, a series of continuous It is not considered a command, and changing the amount of data discard does not seem to improve performance.

After this, the process proceeds to step S18 following steps S15 to S17, and in accordance with the read command parameters stored in step S11, the control circuit 28 controls the disk playback system control circuit 27 and the servo circuit 26 to control the disk. The motor 23 and the feed motor of the pickup 22 are controlled. The pickup 22 detects the reproduced signal and supplies the reproduced signal to the signal processing circuit 29 via the amplifier 24 and the RF detection circuit 25.

The signal processing circuit 29 reproduces data from the reproduction signal supplied from the RF detection circuit 25,
Store in AM30. The buffer RAM 30 stores the supplied data. Immediately thereafter, the buffer RAM 30 transfers the stored data to the host computer, and enables a portion where the transferred data is stored to be written. However, in the read command processing performed in step S18, the overlapped portion of the data is read from the buffer RAM 30, the portion other than the overlapped portion is reproduced from the CD-ROM, and stored in the buffer memory 30.
This is a process of discarding data according to the data discard amount set in steps S17 to S17.

After step S18, the process proceeds to step S19, where the status of the execution result of the read command process of step S18 is set, and the process proceeds to the idle state of step S7. Hereinafter, steps S1 to S19 are repeated. The duplicated data detecting means corresponds to step S12, the data discarding means corresponds to step S18, and the data discarding amount determining means corresponds to steps S15 to S17.

FIG. 3 is a diagram showing a processing procedure of the buffer RAM of the present invention. When a transfer request is received from the host computer, the transfer request is analyzed to determine whether there is any overlap between the previous transfer request data and the current transfer request data, and set the data discard amount. The data supplied from the signal processing circuit 29 shown in FIG. 3A in response to the transfer request is stored in the buffer RAM 30, and immediately thereafter, the data stored in the buffer RAM 30 shown in FIG. 3B is transferred to the host computer. Is done.

Next, according to the set data discard amount, the transfer data is discarded while leaving the data amount indicated by 40 in FIG. 3C. When there is a next transfer request, the portion other than the overlapped portion of the data requested to be transferred and the data stored in the buffer RAM 30 is reproduced from the CD-ROM, and FIG.
By storing the data in the buffer RAM 30 as shown in FIG. 3D, the data to be stored in the buffer RAM 30 shown in FIG. 3E is stored in the buffer RAM, and the overlapping portion of the data is reproduced from the CD-ROM. We are eliminating waste.

As described above, the data already stored in the buffer memory by the previous transfer request and the data of the overlapping portion to be stored in the buffer memory by the present transfer request are left without discarding. It is possible to eliminate the waste of reproducing the duplicated portion of the data from the CD-ROM again, shorten the time required for storing the data, and achieve efficient data transfer.

By determining the amount of data to be discarded in steps S13 to S17, only when the data amount of the overlapping portion of the data does not change (the data amount of the overlapping portion of the data is the same two consecutive times), Since the data discard amount can be updated based on the data amount of the overlapping portion detected in step S12, the data discard amount can be updated except for a random change in the data discard amount, and an efficient data discard amount can be set. The time required to store the data is shortened, and efficient data transfer becomes possible.

In the above-described embodiment, the transfer data is left in the buffer RAM 30 by the amount of overlap in response to a series of commands requesting continuously overlapped data. In an optical disk on which data is recorded,
In some cases, a series of commands requesting data successively separated by a predetermined data interval may be issued.

In this case, to effectively utilize the buffer capacity without leaving useless data in the buffer RAM 30, the data amount of the gap, which is the useless data amount of the transfer request data, is detected, and the data amount of this gap is detected. There is a method in which the data amount of the gap pre-read in the buffer RAM 30 is discarded by making it writable simultaneously with the data already transferred to the host computer based on the above. Here, the pre-reading process is a process of reading data requested to be transferred and storing the data in the buffer memory, and storing data to be continuously reproduced until the capacity of the buffer memory becomes full.

FIG. 4 is a flowchart of a second embodiment showing a buffer RAM processing procedure in the optical disk reproducing apparatus of the present invention. FIG. 4 shows a portion corresponding to steps S12 to S19 in the flowchart of FIG. 1, and other portions are the same as FIG. 1, and thus are omitted in FIG. In step S20, from the parameters of the previous read command and the parameters of the current read command,
The data amount of the gap stored in the buffer 30 by the pre-read process performed in association with the previous read command,
The data amount of the gap to be stored in the buffer RAM 30 is detected by the pre-reading process performed in association with the current read command, and further, whether or not the data amount of the gap has changed is detected. Here, the gap amount is calculated from the difference between the last block address of the block requested to be transferred by the previous read command and the first block address of the block requested to be transferred by the current read command.

According to the detection result of step S20, in step S21, the data stored in the buffer 30 by the pre-read processing performed in association with the previous read command,
It is determined whether there is a gap between the data to be stored in the buffer RAM 30 and a pre-read process performed in association with the current read command. If it is determined that there is a gap, the process proceeds to step S22. Proceed to step S25.

Based on the result of the detection in step S20, in step S22, the data amount of the gap stored in the buffer 30 by the pre-read processing performed in association with the previous read command and the pre-read performed in conjunction with the current read command It is determined whether there is a change in the data amount of the gap to be stored in the buffer RAM 30 by the processing, and if it is determined that there is a change in the data amount of the gap, step S24 is performed.
When it is determined that there is no change in the data amount of the gap, the process proceeds to step S23.

In step S25, the buffer RAM 30
Since there is no gap between the data stored in the buffer RAM 30 and the data to be stored, the data discard amount of the buffer RAM 30 is updated to the initial value (0), and the process proceeds to step S26. In step S23, since there is a change in the data amount of the gap stored in the buffer RAM 30 and the data amount of the gap to be stored, the data amount of the new gap is stored and the data discard amount of the buffer RAM 30 is maintained. Proceed to S26.

In step S24, the buffer RAM 30
Since there is no change in the data amount of the gap stored in the storage unit and the data amount of the gap to be stored, the data discard amount is updated and stored, and the process proceeds to step S26. Here, even if the data amount of the gap slightly changes, the past discard amount is similarly maintained. Thereafter, step S23
25, the process proceeds to step S26, where the buffer RAM
30 to transfer the stored data to the host computer immediately thereafter, and to enable writing of the stored portion of the transferred data,
The gap portion can be written according to the data discard amount set by 23 to 25.

After step S26, the process proceeds to step S27, where the status of the execution result of the read command process of step S26 is set, and the process proceeds to the idle state of step S7 in FIG. Hereinafter, the above procedure is repeated. Here, the gap data amount detecting means corresponds to step S20, the data discarding means corresponds to step S26, and the data discarding amount determining means corresponds to steps S21 to S25.

As described above, data is written together with data transferred to the host computer in response to a change in the data amount of the gap between the data already stored in the buffer RAM 30 and the data to be stored in the buffer RAM 30 by the current transfer request. By discarding by making it possible, the capacity of the buffer RAM 30 is effectively utilized, the hit rate by prefetching is increased, and efficient data transfer becomes possible.

Further, in a case where a series of commands for continuously requesting data separated by a predetermined data interval is issued on an optical disk in which dummy data is recorded every predetermined number of data blocks, useless data is buffered. In order to effectively utilize the buffer capacity without storing the data in the RAM 30, the amount of data in the transfer request gap is detected, and a pre-read process performed accompanying the transfer request is performed based on the amount of data in the gap. The data amount of the gap may not be stored in the buffer RAM 30.

FIG. 5 is a flowchart of a third embodiment showing a buffer RAM processing procedure in the optical disk reproducing apparatus of the present invention. FIG. 5 shows a portion corresponding to steps S12 to S19 of the flowchart of FIG. 1, and other portions are the same as FIG. 1, and thus are omitted in FIG. Steps S20 to S22 correspond to steps S20 to S20 in FIG.
22 and the description is omitted.

If it is determined in step S21 that there is no gap, in step S28, the read-ahead prohibition amount for prohibiting storage in the buffer RAM 30 is set to an initial value (0).
Proceed to step S31. If it is determined in step S21 that there is a gap, and if it is determined in step S22 that there is no change in the data amount of the gap, in step S30, the pre-reading start position is updated so that the gap portion is not written in the buffer RAM 30. Proceed to S31.
Here, the past pre-reading start position is similarly maintained even when the data amount of the gap slightly changes.

If it is determined in step S21 that there is a gap, and if it is determined in step S22 that there is a change in the data amount of the gap, the data amount of the new gap is stored in step S29. Is stored with the previously set prefetching start position, and the process proceeds to step S31. In step S31, the transfer request data is read out and stored in the buffer RAM 30, and the readout data buffer RA is set by the prohibition amount set in the pre-reading of the data following the transfer request data.
The storage in M30 is prohibited. Here, the data storage prohibition means corresponds to step S31, and the data storage prohibition amount determination means corresponds to steps S21, 22, 28-30.

As described above, the change in the gap data amount between the gap data amount already stored in the buffer RAM 30 by the previous transfer request and the gap data amount to be stored in the buffer RAM 30 by the current transfer request. By prohibiting the storage of the gap portion of the data of the pre-reading process stored in the buffer RAM 30 corresponding to the above, the capacity of the buffer RAM 30 is effectively used, the hit rate by the pre-reading is increased, and efficient data transfer is possible. Become. Further, in the case of the third embodiment, the processing for a series of commands for requesting the overlapped data of the first embodiment can also be performed.

[0058]

As described above, according to the first aspect of the present invention, data already stored in the buffer memory by a previous transfer request and data stored in the buffer memory by a current transfer request are stored. By detecting the overlapping portion with the data to be output and leaving the data amount corresponding to the overlapping portion without discarding, the unnecessary portion of reproducing the overlapping portion of the data from the CD-ROM is eliminated again, and the time required for storing the data is reduced. By doing so, efficient data transfer becomes possible.

According to the second aspect of the present invention, by determining the amount of data to be discarded by the data discarding amount determining means, the data amount of the overlapping portion of the data does not change (2).
The data discarding amount can be updated based on the data amount of the overlapping portion detected by the duplicated data detecting means only when the data amount of the overlapping portion of the data is the same continuously). In addition, the data discard amount can be updated, an efficient data discard amount can be set, the time required for storing data can be shortened, and efficient data transfer can be performed.

According to the third aspect of the present invention, the data amount of the gap generated in the pre-reading process performed in association with the transfer request is detected, and the data amount of the gap is transferred to the host computer after the transfer. By discarding the data together with the data, it is possible to increase the hit rate by pre-reading, discard the useless gap, and efficiently utilize the capacity of the buffer memory, thereby enabling efficient data transfer.

According to the fourth aspect of the present invention, a data amount of a gap generated in a prefetch process performed in association with the transfer request is detected, and data corresponding to the gap is stored in the buffer memory. , The hit ratio by pre-reading is increased, and efficient use of the capacity of the buffer memory enables efficient data transfer. Further, the invention according to claim 1 can be performed together.

According to the fifth aspect of the present invention, the data amount of the gap is not changed by determining the data amount of the gap by the pre-reading process to be discarded by the data discard amount determining means (two consecutive times). Only when the data amount of the gap is the same, the data discard amount can be updated based on the data amount of the gap detected by the gap data amount detection means, and the data discard amount is updated except for a random change in the data discard amount. As a result, an efficient data discard amount can be set, and efficient data transfer becomes possible.

According to the present invention, the data amount of the gap is determined by the pre-reading process for inhibiting the storage by the data storage inhibition amount determining means, so that the data amount of the gap is not changed. The data storage prohibition amount can be updated based on the data amount of the gap detected by the gap data amount detection means, and the data storage prohibition amount can be updated except for a random change in the data storage prohibition amount, so that efficient data storage prohibition is achieved. The amount can be set, and efficient data transfer becomes possible.

[Brief description of the drawings]

FIG. 1 shows a buffer RA in an optical disk reproducing apparatus according to the present invention.
9 is a flowchart of the first embodiment illustrating the M processing procedure.

FIG. 2 is a configuration diagram of a CD-ROM device according to one embodiment of the present invention.

FIG. 3 is a diagram showing a processing procedure of a buffer RAM of the present invention.

FIG. 4 is a diagram illustrating a buffer RA in the optical disk reproducing apparatus according to the present invention;
13 is a flowchart of a second embodiment illustrating an M processing procedure.

FIG. 5 is a diagram illustrating a buffer RA in the optical disk reproducing apparatus according to the present invention;
15 is a flowchart of a third embodiment illustrating an M processing procedure.

FIG. 6 is a diagram showing a processing procedure of a conventional buffer RAM.

[Explanation of symbols]

 Reference Signs List 21 optical disk 22 optical pickup 23 disk motor 24 amplifier 25 RF detection circuit 26 servo circuit 27 disk reproduction system control circuit 28 control circuit 29 signal processing circuit 30 buffer RAM 31 RAM 32 program ROM 33 RAM controller 40, 41, 42, 43 overlap part

Claims (6)

[Claims] 1. A method for reproducing data from a signal read from an optical disk in response to a transfer request from a host computer, storing the reproduced data in a buffer memory, and transmitting the data stored in the buffer memory to the host computer. After the transfer, the data transferred to the host computer is discarded from the buffer memory. In the optical disc reproducing apparatus, the data already stored in the buffer memory by the previous transfer request and the data stored in the buffer memory by the current transfer request are stored. Duplicate data detecting means for detecting an overlapping portion with the data to be performed; and leaving an amount of data corresponding to the overlapping portion in the buffer memory, and subtracting the amount of data corresponding to the overlapping portion from the buffer memory. Data discarding means for discarding Disk reproducing apparatus. 2. The optical disk reproducing apparatus according to claim 1, wherein a data amount of a duplicate portion detected last time by said duplicate data detecting means and a data amount of a duplicate portion of data detected by said duplicate data detecting means at this time. An optical disc reproducing apparatus, comprising: a data discard amount determining means for determining an amount of data to be discarded by the data discarding means by comparing. 3. Data is reproduced from a signal read from an optical disk in response to a transfer request from a host computer and a signal read by a pre-read process performed in association with the transfer request. An optical disc device for storing in a buffer memory, transferring data corresponding to a transfer request from a host computer stored in the buffer memory to the host computer, and then discarding the data transferred to the host computer from the buffer memory. A gap data amount detecting means for detecting a data amount of a gap generated in a prefetch process performed in association with the transfer request; and a data amount obtained by adding the gap amount to data transferred from the buffer memory from the buffer memory. Characterized by having a data discarding means that performs Disk reproducing apparatus. 4. Reproducing data from a signal read from an optical disk in response to a transfer request from a host computer and a signal read by a pre-reading process performed in conjunction with the transfer request, and reproducing the reproduced data. An optical disc device for storing in a buffer memory, transferring data corresponding to a transfer request from a host computer stored in the buffer memory to the host computer, and then discarding the data transferred to the host computer from the buffer memory. A gap data amount detecting unit for detecting a data amount of a gap generated in a pre-read process performed in association with the transfer request; and a data storage inhibiting unit for inhibiting storage of data corresponding to the gap in the buffer memory. An optical disk reproducing apparatus comprising: 5. The optical disk reproducing apparatus according to claim 3, wherein the data amount of the gap detected by the gap data amount detecting means at the time of the previous transfer request and the gap data amount detected by the gap data amount detecting means at the time of the current transfer request. An optical disc reproducing apparatus, comprising: a data discard amount determining unit that determines the data amount discarded by the data discard unit by comparing the data amount of the gap. 6. The optical disk reproducing apparatus according to claim 4, wherein the gap data amount detected by said gap data amount detecting means at the time of a previous transfer request and said gap data amount detected by said gap data amount detecting means at a current transfer request. An optical disk reproducing apparatus, comprising: a data storage prohibition amount determining unit that compares the data amount of the gap with the data amount of the gap and determines a data amount that is prohibited from being stored in the buffer memory by the data storage prohibition unit.