JP2991227B2 - Optical disk drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an optical disk device.

[0002]

2. Description of the Related Art In a navigation system, map data recorded on an optical disk is read by an optical disk device. This map data is frequently updated due to new roads, changes in road regulations, and the like. When a read-only optical disk such as a CD-ROM is used for information that needs to be updated frequently, data cannot be rewritten.
-Periodic replacement with ROM is performed. However, there is a problem that it is uneconomical to replace the optical disk periodically and that old data must be used until the optical disk is replaced.

Therefore, when writing information that needs to be frequently updated to an optical disc, a hybrid disc or a rewritable optical disc may be used as the optical disc. Here, a hybrid disk is a disk that is divided into two parts, an inner circumference and an outer circumference.
The inner peripheral portion is a read-only region, and the outer peripheral portion is a rewritable region. When this hybrid disc is used, when updating the information recorded in the inner peripheral portion, the updated information is written in a rewritable area in the outer peripheral portion. Therefore, the to-be-updated information and the updated information are recorded at separate positions.

[0004] In a rewritable optical disk, when the recording information is updated, the information to be updated can be directly rewritten with the updated information. However, if the rewriting affects other information,
It is necessary to write to an area where no information is recorded. In this case, the update information is written at a position apart from the position where the corresponding information to be updated is recorded.

[0005]

As described above, if the update information is recorded at a location remote from the information to be updated, the information recorded on the optical disc becomes discontinuous, and the This leads to performance degradation. In the case of a rewritable disc, discontinuity of information can be prevented by rewriting not only update information but also all recorded information. However, in that case, rewriting time will be significantly increased.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical disk apparatus which can record update information at a position physically close to the information to be updated and has improved access performance.

[0007]

In order to achieve the above object, the present invention provides an optical disk apparatus using an optical disk having two layers for recording information, wherein one of the information recording layers of the optical disk is a read-only layer. When the other information recording layer is used as a layer for both reading and writing, and information recorded in one information recording layer is updated, the update information is located at a position of the other information recording layer physically close to the information to be updated. Means for recording, when reading information from the optical disc, when the information to be read is not updated, the information recorded on one information recording layer is read, and the information to be read is updated. In some cases, means for reading the update information recorded on the other information recording layer is provided.

As described above, by recording the update information and the information to be updated on different information recording layers, the update information can be recorded at the same position as the information to be updated. Further, even when the update information cannot be recorded at the same position as the information to be updated, it can be recorded at a very close position. Therefore, when reading the information recorded on the optical disk, the updated information can be read at the same position as or near the updated information, so that the continuity of the information recorded on the optical disk can be maintained, and the access characteristic can be improved. Is improved.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to the drawings. FIG. 3 shows a schematic configuration of the optical disk device. An optical disc 1 having two information recording layers 2 and 3 is used. In the following description, the lower information recording layer 2 is referred to as a first layer, and the upper information recording layer 3 is referred to as a second layer.

In the optical disc 1 of this embodiment, the second layer 3
Is a read-only layer, on which map data is recorded.
On the other hand, the first layer 2 is a layer for both reading and writing. When the map data is updated due to a change in a road, a road regulation, or the like, update data A ′ is written in the first layer 2. The update data A ′ is written in the physically same position immediately below the corresponding update target data A. If the data cannot be written at the same position, the update data A ′ is written at a position close to the data A to be updated.

The first layer 2 also records information relating to the update of the written update data A '. The information on the update includes the address of the updated data A, the recording address of the updated data A ', the updated data A and the updated data A'.
Related information is included. An optical head 4 for reading and writing data facing the first layer 2 and the second layer 3
Is provided. The optical head 4 reads data recorded on the second layer 3 by focusing on the second layer 3. The optical head 4 focuses on the first layer 2 to read out or write the update data recorded on the first layer 2.

The optical head 4 can be moved in the radial direction of the optical disk 1 by the drive unit 5. Optical head 4
The control of the focus distance and the control of the drive unit 5 are performed by the control unit 6. The control unit 6 includes a CPU, a memory, and the like. The operation of the control unit 6 will be described with reference to the flowcharts of FIGS. FIG. 1 shows an operation at the time of updating data.

In step S1, information on data update performed in the past from the first layer 2 of the optical disk 1 is read and stored in a memory. In step S2, the physical position of the data A to be updated in the second layer 3 is calculated. In step S3, it is determined whether or not the update data A 'can be written to the first layer 2 at the same position as the physical position calculated in step S2. As an example of a case where writing cannot be performed, there is a case where another update data has already been recorded within a range where the update data A ′ is to be written.

If it is determined in step S3 that writing cannot be performed, the process proceeds to step S4, where the area where update data can be written at a position close to the physical position calculated in step S2 is set as the first area. Search on layer 2. Step S5
Then, the optical head 4 is moved to the physical position calculated in step S2 or the writable area searched in step S4, and the updated data is written to the address.

In step S6, information relating to the update of the currently updated data is stored in the memory. Information on this update includes the updated data A as described above.
, The recording address of the update data, and related information between the two. Further, the information relating to the update of the data is recorded on the optical disc 1 when the update of all the data is completed.

FIG. 2 shows the operation at the time of data reading.
In step S11, file / address information is read from the optical disk 1 and stored in the memory. In step S12, information relating to the data update is read from the optical disc 1 and stored in the memory.

In step S13, the process waits for an access request to be issued.
Proceed to 14. In step S14, the optical head 4 is moved to the address on the second layer 3 where the data to be accessed is stored. In step S15, it is determined whether or not the data to be accessed has been updated in the past based on the information on the data update. If the data has not been updated, the process proceeds to step S16, and the data of the second layer 3 is read. Therefore, for data that has not been updated, the data is read immediately after accessing the address.

If it is determined in step S15 that the data to be accessed has been updated, step S17 is performed.
Then, the optical head 4 is focused on the first layer 2 on which the update data is recorded. Then, step S1
At 8, the updated data is read, and the focus of the optical head 4 is returned to the second layer 3. In this step S18, the update data A 'is normally stored immediately below the data A to be updated. Therefore, after accessing a predetermined address, the update data A' is read only by moving the focus. Become. If the update data A 'is not recorded immediately below the data A to be updated, the optical head 4 is moved to the recorded position to read the update data A'. Even in this case, since the update data A 'is stored at a position close to the data A to be updated, the access time is reduced as compared with the conventional one.

In step S19, it is determined whether the reading of the requested data has been completed, and the process returns to step S15 to continue reading the data until the reading is completed. When the reading of the requested data is completed, the process returns to step S13, and waits until the next access request is issued. As is apparent from the above description, the update data A is recorded at or near the same position as the data to be updated A ′, so that the continuity of the data can be maintained and the deterioration of the access performance can be prevented. .

[0020]

According to the present invention, it is possible to record the update information at a position physically close to the information to be updated, and it is possible to obtain an optical disk device with improved access performance.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of an optical disk device of the present invention.

FIG. 2 is a flowchart showing an operation of the optical disk device of FIG. 1 when updating data.

FIG. 3 is a flowchart showing an operation of the optical disk device of FIG. 1 when reading data.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Optical disk 2 ... 1st layer 3 ... 2nd layer 4 ... Optical head 5 ... Drive part 6 ... Control part

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Claims (1)

(57) [Claims] In an optical disk apparatus using an optical disk having two layers for recording information, one information recording layer of the optical disk is used as a read-only layer and the other information recording layer is used as a read / write layer. Means for updating information recorded on the one information recording layer, means for recording update information at a position physically close to the information to be updated on the other information recording layer, and reading information from the optical disc. When the information to be read has not been updated, the information recorded in the one information recording layer is read, and when the information to be read has been updated, the information is read to the other information recording layer. An optical disk device comprising: means for reading recorded update information.