JP2010152981A - Method and device for reading optical disk - Google Patents

Abstract

An optical disk reading method for improving the reading speed when an optical disk in which a series of data is recorded at discontinuous physical addresses is read into a buffer for prefetch cache processing is provided.
An optical disk reading method refers to a DFL created to indicate a correspondence relationship between a physical address of a replacement source and a physical address of a replacement destination when a data block is replaced with another data block. Whether the physical address to be read next matches the physical address of the exchange source indicated in the DFL is compared (step S2). If the physical address to be read next matches the physical address of the exchange source (step S2: YES), After a spare area for storing the data block of the exchange destination physical address is secured in the buffer 118 (step S4), the data blocks from the exchange source physical address to the exchange destination physical address are sequentially buffered 118. (Steps S1 to S10), and the read physical address data of the exchange destination is copied to the spare area ( Step S8).
[Selection] Figure 4

Description

  The present invention relates to an optical disk reading method and apparatus for efficiently pre-reading cache data on optical disk data.

  When an optical disk is read by an optical disk device, it is often read sequentially. In this case, when a read request for a certain address is issued, it is efficient to read the data at the destination address first. Therefore, a read-ahead cache is used as a method of reading an unrequested address in advance and storing it in a buffer. The data stored in the buffer preferably has consecutive logical addresses. Normally, when an optical disk is read from a requested physical address, data is stored in a buffer of the optical disk apparatus logically continuously.

  On the other hand, for example, a write-once Blu-ray disc uses a technique called Logical Overwrite (LOW). This technique allows a write-once disc that cannot be rewritten to be logically overwritten using a defect management function for managing data defects on the disc. The data to be overwritten is replaced with a different physical address. For example, when the data at the physical address “100100” is rewritten, new data is added to “100160” and the correspondence is recorded in a table called a defect list (DFL) shown in FIG. The defect list in FIG. 1 indicates that the data at the address “100140” is replaced with the data at the address “1001A0”. In addition, since the data for the address “100160” has already been replaced, the next data must be stored at the next available address after the address “100160”. Accordingly, the data at the address “100160” is shown in the defect list as being replaced with the data at the address “1001C0”.

When data recorded by logical overwrite is read by a prefetch cache, it is necessary to perform an alternative process according to the defect list. When trying to store data in the buffer logically continuously, the order of the physical addresses to be read is fluctuated and jumped, and becomes discontinuous (see, for example, Patent Document 1).
JP 2008-10122 A

  When the optical disk is prefetched from the address “1000E0” shown in FIG. 2 according to the defect list of FIG. 1, the data block at the address “1000E0” is first read. Subsequently, since data is substituted for the next address “100100”, the data block at address “100160” is read by jumping according to the defect list. Since the data at the next address “100120” is not substituted, the data block is read by returning to the address “100120”. In this way, data “1000E0”, “100160”, “100120”, “1001A0”, and “1001C0” are stored in the buffer in the logical address order. In this example, three seek operations are required.

  As can be seen from the above, when the prefetch cache process is performed while the order is replaced according to the defect list, a seek operation frequently occurs. In the seek operation, a jump time and a rotation waiting time are generated, so that the reading speed is lowered and the reproduction performance is lowered.

  Moreover, not only in the case of logical overwrite, but also when a defect occurs in a cluster of optical disks and is replaced with a cluster of different addresses, a series of data is stored at discontinuous physical addresses. The same problem occurs.

  The present invention has been made in view of the above circumstances, and an optical disc reading method for improving the reading speed when reading an optical disc in which a series of data is recorded at discontinuous physical addresses into a buffer for prefetch cache processing, and An object is to provide such a device.

  The optical disk reading method of the present invention is an optical disk reading method for reading a series of data blocks recorded discontinuously at physical addresses of an optical disk and logically related to a temporary storage area. When the data block is exchanged with another data block, referring to a table created to show the correspondence between the exchange source physical address and the exchange destination physical address, the physical address to be read next is Comparing with the physical address of the exchange source shown in the table. Furthermore, when the physical address to be read next does not match the physical address of the exchange source, there is a step of reading the data block of the next physical address into the temporary storage area. If the physical address to be read next matches the physical address of the exchange source, a spare area for storing the data block of the physical address of the exchange destination is secured in the temporary storage area, and then the physical address of the exchange source To the physical address of the exchange destination are sequentially read into the temporary storage area, and the read data of the physical address of the exchange destination is copied to the spare area.

  The optical disk reading device of the present invention includes an optical pickup, a temporary storage area, a table memory, and a control unit. An optical pickup reads a data block of an optical disc in which a series of logically related data blocks are recorded discontinuously at physical addresses. The temporary storage area temporarily stores the data block read by the optical pickup. The table memory stores a table created to show the correspondence between the exchange source physical address and the exchange destination physical address when the data block recorded on the optical disc is exchanged. The control unit controls the optical pickup so that the data blocks of the optical disc are sequentially read into the temporary storage area from the physical address requested to be read. The control unit refers to the table to compare whether the physical address to be read next matches the physical address of the exchange source shown in the table, and the physical address to be read next matches the physical address of the exchange source If not, read the data of the next physical address into the temporary storage area, and if the physical address to be read next matches the physical address of the exchange source, a spare area for storing the data of the physical address of the exchange destination After securing in the temporary storage area, the data from the physical address of the exchange source to the physical address of the exchange destination is read into the temporary storage area, and the read data of the physical address of the exchange destination is read into the spare area Duplicate.

  As a result, all data blocks at the physical address of the exchange destination are read, and the data block of the exchange destination address is copied to the reserved spare area. Therefore, the data block can be stored in the temporary storage area without seeking from the exchange source to the exchange destination physical address and in the logical address order.

  According to the optical disk reading method and apparatus of the present invention, the playback time of the optical disk can be remarkably shortened as much as the number of seeks can be reduced as compared with the prior art.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 3 is a diagram showing a schematic configuration of the optical disk reading apparatus.

  The optical disc 50 to be read is a write-once optical disc such as a BD (Blu-ray disc), DVD, or CD.

  As shown in FIG. 3, the optical disc reading apparatus 100 includes an optical pickup 102, an RF signal processing unit 104, a decoder 106, an address register 108, a comparator 110, a defect list memory (DFL memory) 112, a hold list memory 114, a memory controller. 116, a buffer 118, an interface 120, and a CPU 122.

  The optical pickup 102 irradiates the rotating optical disk 50 with laser light, and reads data recorded on the optical disk 50 by the reflected light. The read signal is sent to the RF signal processing unit 104, where waveform shaping and digital signal processing are performed.

  The decoder 106 demodulates the signal from the RF signal processing unit 104 into address data and main data (block). First, the address data is demodulated. The address register 108 stores demodulated address data as a physical address of the optical disk 50 currently read. The comparator 110 compares the address data (physical address) stored in the address register 108 with the address data (physical address) stored in the DFL memory 112 and the hold list memory 114, and determines whether they match. to decide.

  When the data block on the optical disc 50 is exchanged for another data block, the DFL memory 112 indicates a correspondence relationship between the physical address where the exchange source data was stored and the physical address where the exchange destination data is stored. Store the table created. Data block exchange is performed, for example, when a physical format is executed and a defect is detected in the data block. The contents of the data block having a defective physical address are restored and rewritten to a data block having a new physical address having no defect. Alternatively, the exchange of data blocks is also executed when erasing a pseudo old data block and recording data to be rewritten in place of the old data block at a new physical address for logical overwriting. The DFL memory 112 is usually created when a data block is defective. However, in this embodiment, it may be used for logical overwrite.

  The pending list memory 114 is a table indicating which data block is stored in which cluster when data is copied (moved) in the buffer 118. Details will be described later.

  If there is no problem such as an error in the data demodulated by the decoder 106, the memory controller 116 issues a write request to the buffer 118 to the decoder.

  The buffer (temporary storage area) 118 has a storage area in units of a plurality of clusters, and temporarily stores the data blocks output from the decoder 106 in the clusters in order. In this embodiment, it is assumed that the capacity of the data block of the optical disc 50 corresponds to the capacity of the cluster of the buffer 118.

  The interface 120 transmits / receives data to / from the host under the control of the CPU 122 in accordance with a request from the host.

  Next, the optical disk reading method of this embodiment will be described in detail.

  FIG. 4 is a flowchart showing the flow of the optical disk reading method. The operation is executed by each of the above-described units, and each unit is controlled by the CPU 122. The optical disk 50 is read for prefetch cache processing.

  First, the physical address of the optical disc 50 that has started to be read is acquired by the optical pickup 102, the RF signal processing unit 104, and the decoder 106 (step S1).

  The acquired physical address is transmitted from the address register 108 to the comparator 110, where it is compared with the physical address of the exchange source stored in the DFL memory 112 and whether it matches the defect list (DFL). It is examined (step S2). For example, in the case of the defect list shown in FIG. 1, since “100100”, “100140”, and “100180” are registered as the physical addresses of the exchange source, the physical addresses of the optical disk 50 that have started reading are registered. It is checked whether it matches any of the exchanged physical addresses.

  When the acquired physical address matches the physical address of the exchange source in the defect list (step S2: YES), all data from the matched physical address of the exchange source to the corresponding physical address of the exchange destination is read. Is determined by the CPU 122 to be less than the remaining storage capacity (remaining capacity) of the buffer 118 (step S3). For example, it is determined whether the capacity of four data blocks from the exchange source address “100100” to the exchange destination address “100160” shown in FIG.

  When the remaining amount of the buffer 118 is sufficient (step S3: YES), the CPU 122 stores the data block of the current physical address as a dummy data block in the next cluster of the buffer 118, and the cluster in which the dummy data block is stored. Adds a hold list indicating that the data block of the physical address of the exchange destination is held for saving (step S4). The cluster in which the dummy data block is stored is secured as a spare area to be replaced later with the data block of the exchange destination physical address.

  When the remaining amount of the buffer 118 is insufficient to read all the data up to the physical address of the replacement destination (step S3: NO), the CPU 122 seeks the optical pickup 102 to the physical address of the replacement destination and replaces it. The data block of the previous physical address is read and stored in the buffer 118 (step S5).

   It is determined whether the physical address acquired in step S1 corresponds to the hold list in the hold list memory 114 (step S6). Here, the CPU 122 determines whether the data block of the read physical address is a data block to be stored in the spare area of the buffer 118 with reference to the pending list.

  If the acquired physical address is in the hold list (step S6: YES), the data block read in step S4 is to be replaced with a spare area in the buffer 118. It is copied to the cluster (step S7). By copying the exchange destination data block in the spare area, the data block is stored in the buffer 118 in the order of logical addresses. Since there is no spare area due to copying, the reserved list for the spare area is deleted and updated (step S8). The list is updated by the CPU 122.

  If the acquired physical address is not in the hold list (step S6: NO), the next process proceeds.

  On the other hand, returning to step S2, if the acquired physical address does not match the physical address of the defect list exchange source (step S2: NO), the physical address acquired in step S1 is the hold list in the hold list memory 114. Is determined (step S9). Here, the CPU 122 determines whether the data block of the physical address to be acquired at present is a data block to be stored in the spare area of the buffer 118 with reference to the pending list.

  If the acquired physical address is in the hold list (step S9: YES), the data block of the physical address that is currently being read is replaced with a spare area in the buffer 118. It is copied to the cluster in the buffer 118 shown in the hold list (step S10). By copying the exchange destination data block in the spare area, the data block is stored in the buffer 118 in the order of logical addresses. Since there is no spare area due to copying, the reserved list for the spare area is deleted and updated (step S11). The list is updated by the CPU 122.

  If the acquired physical address is not in the hold list (step S9: NO), the data block is acquired from the optical disc 50 as it is and stored in the buffer 118 (step S12).

  Since the prefetch cache processing is executed until the capacity of the buffer 118 is exhausted, the remaining amount of the buffer 118 is detected by the CPU 122 (step S13). If the remaining amount of the buffer 118 remains (step S13: NO), the processing from step S1 is repeated. When the remaining amount of the buffer 118 does not remain (step S13: YES), reading of the optical disk for the prefetch cache process is terminated.

  Next, an optical disk reading method will be described using a specific example.

  FIG. 5 is a diagram showing the transition of the data in the buffer and the hold list, and FIG. 6 is a diagram showing the reading order of the optical disc.

  Here, it is assumed that the DFL shown in FIG. 1 is stored in the DFL memory 112 and is read sequentially from the physical address “1000E0” of the optical disk 50 as shown in FIG. 6 for the prefetch cache processing. Assume that the order of the physical addresses of the optical disk 50 is the same as in FIG. The buffer 118 is provided with 10 clusters of pages 0 to 9 as storage areas.

  (1) Reading of the optical disk 50 starts, and first, it is determined whether the physical address “1000E0” of the optical disk 50 matches the exchange source address of the DFL of FIG. Since they do not match, it is determined whether this physical address “1000E0” matches the pending list. Since the pending list has not yet been created, it does not match. Therefore, the data block of the physical address “1000E0” is stored in page 0 of the buffer 118 as it is.

  (2) It is determined whether the next physical address “100100” of the optical disc 50 matches the exchange source address of the DFL in FIG. Since they match, it is determined whether the data amount from the exchange source physical address “100100” to the exchange destination physical address “100160”, that is, the capacity of four data blocks remains in the buffer 118. In the buffer 118, nine clusters of pages 1 to 9 remain. Therefore, since the buffer 118 has sufficient remaining capacity, page 1 of the buffer 118 is reserved for the data block of the physical address “100160” as a spare area. For securing, page 1 stores dummy data. The dummy data is, for example, data of the physical address “100100” that has become unnecessary. At the same time, the CPU 122 creates a pending list indicating that the data block of the physical address “100160” is stored in page 1 of the buffer 118.

  Further, it is determined whether the physical address “100100” matches the hold list. Since only the physical address “100160” is registered in the hold list, they do not match.

  (3) It is determined whether the next physical address “100120” of the optical disc 50 matches the exchange source address of the DFL of FIG. Since they do not match, it is determined whether this physical address “100120” matches the pending list. Since only the physical address “100160” is registered in the hold list, they do not match. Therefore, the data block of the physical address “100120” is stored in page 2 of the buffer 118 as it is.

  (4) It is determined whether the next physical address “100140” of the optical disc 50 matches the exchange source address of the DFL in FIG. Since they match, it is determined whether the data amount from the physical address “100140” of the exchange source to the physical address “1001A0” of the exchange destination, that is, the capacity for four data blocks remains in the buffer 118. In the buffer 118, seven clusters of pages 3 to 9 still remain. Therefore, since the buffer 118 has sufficient remaining capacity, page 3 of the buffer 118 is reserved for the data block of the physical address “1001A0” as a spare area. In order to ensure, page 3 stores dummy data. The dummy data is data of the physical address “100140”.

  At the same time, the CPU 122 adds a pending list indicating that the data block of the physical address “1001A0” is stored in page 3 of the buffer 118. Therefore, in this stage 4, the pending list associates page 1 with the physical address “100160” and page 3 with the physical address “1001A0”.

  Further, it is determined whether the physical address “100140” matches the pending list. Since they do not match, proceed to the next step.

  (5) It is determined whether the next physical address “100160” of the optical disc 50 matches the exchange source address of the DFL of FIG. Since they match, it is determined whether the data amount from the exchange source physical address “100160” to the exchange destination physical address “1001C0”, that is, the capacity of four data blocks remains in the buffer 118. The buffer 118 still has six clusters of pages 4-9. Accordingly, since the buffer 118 has sufficient remaining capacity, the page 4 of the buffer 118 is reserved for the data block of the physical address “1001C0” as a spare area. In order to ensure, page 4 stores dummy data. Here, the dummy data is data of the physical address “100160”.

  At the same time, the CPU 122 adds a pending list indicating that the data block of the physical address “1001C0” is stored in page 4 of the buffer 118. Therefore, in this stage 5, the hold list associates page 1 with the physical address “100160”, page 3 with the physical address “1001A0”, and page 4 with the physical address “1001C0”.

  (6) It is determined whether the physical address “100160” matches the hold list. It matches the physical address “100160” of the hold list. Therefore, the data block of physical address “100160” stored in page 4 of buffer 118 is copied to page 1 of buffer 118 in accordance with the pending list. Since the physical address “100160” of the hold list is unnecessary, it is deleted and the hold list is updated.

  (7) It is determined whether the next physical address “100180” of the optical disc 50 matches the exchange source address of the DFL in FIG. Since they do not match, it is determined whether this physical address “100180” matches the pending list. Since they do not match, the data block of the physical address “100180” is stored in page 5 of the buffer 118 as it is.

  (8) It is determined whether the next physical address “1001A0” of the optical disc 50 matches the exchange source address of the DFL of FIG. Since they do not match, it is determined whether this physical address “1001A0” matches the pending list. Matches the pending list. Therefore, first, the data block of the physical address “1001A0” is stored in the next page 6 of the buffer 118.

  (9) Subsequently, the data block of the physical address “1001A0” stored in page 6 of the buffer 118 is copied to page 3 of the buffer 118 according to the pending list. Since the physical address “1001A0” of the hold list is unnecessary, it is deleted and the hold list is updated.

  (10) It is determined whether the next physical address “1001C0” of the optical disc 50 matches the exchange source address of the DFL in FIG. Since they do not match, it is determined whether this physical address “1001C0” matches the pending list. Matches the pending list. Therefore, first, the data block of the physical address “1001C0” is stored in the next page 7 of the buffer 118. Subsequently, the data block of the physical address “1001C0” stored in page 7 of the buffer 118 is copied to page 4 of the buffer 118 according to the pending list. Since the physical address “1001C0” of the hold list is unnecessary, it is deleted and the hold list is updated.

  Similarly, the prefetch cache processing is executed until the capacity of the buffer 118 is exhausted.

  In the example of FIG. 5, as a result, as shown in FIG. 6, the data block on the optical disc 50 can be read without seeking once.

  As described above, in this embodiment, even when data blocks on the optical disk 50 are exchanged and logically related data is stored at discontinuous physical addresses, the physical address of the exchange destination is changed from the exchange source. Read all data blocks. Then, the data block of the exchange destination address is copied to the reserved spare area. Therefore, the data block can be stored in the buffer 118 in the logical address order without seeking the optical pickup 102 from the exchange source to the physical address of the exchange destination.

  In particular, it is confirmed whether or not the remaining capacity of the buffer 118 is sufficient. If there is enough, a spare area for copying the physical address data of the exchange destination is secured in the buffer 118 and then the data of the physical address of the exchange destination. Read all the blocks. Therefore, seeking can be omitted and reading efficiency can be improved. When the remaining capacity of the temporary storage area is not sufficient, the data block is read and read as usual. At least when the remaining amount of the buffer 118 is sufficient, the seek can be omitted, so that the reading speed can be improved, and the reproduction performance can be improved.

  In the above embodiment, the data block of the physical address of the exchange destination is copied to the spare area, and the data block of the copy source is held in the buffer 118 as it is. For example, in the step 6 of FIG. 5, the data block of the physical address “100160” is left on the page 4. However, after copying, the copy source data block may be deleted from the buffer 118. In this way, it is not necessary to detect a page that is not substantially used, and it is sufficient to search for the page of the youngest address that is not used in the buffer 118 when the spare area is secured next time.

It is a figure which shows the example of a defect list. It is a figure which shows the reading order of an optical disk, and the memory | storage order in a buffer. It is a figure which shows schematic structure of an optical disk reader. It is a flowchart which shows the flow of the optical disk reading method. It is a figure shown in transition of the data in a buffer, and a pending | holding list. It is a figure which shows the reading order of an optical disk.

Explanation of symbols

50 optical disc,
100 optical disk reading device,
102 Optical pickup,
104 signal processing unit,
106 decoder,
108 Address register,
110 comparator,
112 Defect list (DFL) memory,
114 Pending list memory,
116 memory controller;
118 buffers,
120 interface.

Claims (8)

An optical disk reading method for reading a series of data blocks recorded discontinuously at physical addresses of an optical disk and logically related to a temporary storage area,
When the data block is exchanged with another data block, referring to a table created to show the correspondence between the exchange source physical address and the exchange destination physical address, the physical address to be read next is Comparing with the physical address of the exchange source shown in the table;
When the physical address to be read next does not match the physical address of the exchange source, reading the data block of the next physical address into the temporary storage area;
If the physical address to be read next matches the physical address of the exchange source, a spare area for storing the data block of the physical address of the exchange destination is secured in the temporary storage area, and then the physical address of the exchange source Sequentially reading data blocks from the physical address of the exchange destination to the temporary storage area, and copying the read physical address data of the exchange destination to the spare area;
An optical disc reading method comprising: When the physical address to be read next matches the physical address of the exchange source, it is confirmed whether the capacity for reading the data of all physical addresses from the exchange source to the exchange destination remains in the temporary storage area Further comprising steps,
If the capacity remains, execute the step of copying the data block of the physical address of the exchange destination to the spare area,
2. The optical disk reading method according to claim 1, wherein when there is no remaining capacity, the process proceeds to the physical address of the exchange destination without reading the data block, and only the data block of the physical address of the exchange destination is read. When reading data blocks of all physical addresses from the exchange source to the exchange destination, creating a hold list indicating that the spare area is reserved for the data block of the exchange destination physical address; In addition,
3. The optical disk reading method according to claim 1, wherein when the physical address of the exchange destination is read, the hold list is referred to and a data block of the physical address of the exchange destination is copied to the spare area.   The optical disc reading method according to claim 1, wherein the optical disc is a write-once disc. An optical pickup for reading data blocks of an optical disc in which a series of logically related data blocks are recorded discontinuously at physical addresses;
A temporary storage area for temporarily storing data blocks read by the optical pickup;
A table memory for storing a table created to indicate the correspondence between the physical address of the exchange source and the physical address of the exchange destination when the data block recorded on the optical disc is exchanged;
A control unit for controlling the optical pickup so as to sequentially read the data blocks of the optical disc from the physical address requested to be read into the temporary storage area;
Have
The control unit refers to the table and compares whether the physical address to be read next matches the physical address of the exchange source indicated in the table,
If the physical address to be read next does not match the physical address of the exchange source, the data of the next physical address is read into the temporary storage area,
If the physical address to be read next matches the physical address of the exchange source, a spare area for storing the data of the physical address of the exchange destination is secured in the temporary storage area, and then the physical address of the exchange source An optical disk reading device for reading data up to the physical address of the exchange destination into the temporary storage area and copying the read data of the physical address of the exchange destination into the spare area. The controller is
If the physical address to be read next matches the physical address of the exchange source, check whether the capacity for reading the data of all physical addresses from the exchange source to the exchange destination remains in the temporary storage area. ,
If the capacity remains, execute the step of copying the data block of the physical address of the exchange destination to the spare area,
6. The optical disk reading device according to claim 5, wherein when there is no remaining capacity, the optical pickup is advanced to the physical address of the exchange destination without reading the data block, and only the data block of the physical address of the exchange destination is read. In a case where data blocks of all physical addresses from the exchange source to the exchange destination are read, the reserve area further indicates that the spare area is reserved for the data block of the physical address of the exchange destination ,
The hold list is updated every time the spare area is put on hold by the control unit,
The control unit updates the hold list each time a spare area is put on hold, and when reading the physical address of the exchange destination, refers to the hold list and reads the data block of the physical address of the exchange destination 7. The optical disk reading device according to claim 5 or 6, wherein the optical disk is copied to a spare area.   The optical disk reading device according to claim 5, wherein the optical disk is a write-once disk.