JPH09139022A - Optical disk drive - Google Patents

Abstract

(57) Abstract: An optical disk device is provided which enables update information to be recorded at a position physically close to the information to be updated and improves access performance when reading information. A two-layer type optical disc is used as an optical disc, one layer is used as a read-only layer, and the other layer is used as a read / write layer. When updating the information recorded in one layer, it is determined whether the update information can be recorded in the same position in the other layer S3, and the update data is recorded in the same position or a nearby position S5. As a result, the continuity of the data recorded on the optical disc can be maintained and the access characteristics can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention 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 road construction, changes in road regulations, and the like. When a read-only optical disc such as a CD-ROM is used for information that needs to be updated frequently, the data cannot be rewritten. Therefore, the CD on which the updated data is recorded is recorded.
-Periodically replaced with ROM. However, it is uneconomical to replace the optical disk regularly, and there is a problem that old data must be used until the optical disk is replaced.

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

Further, in the rewritable type optical disc, when the recorded information is updated, the updated information can be directly rewritten into the updated information. However, if other information is affected by the rewriting, update information is
It is necessary to write in the area where no information is recorded. In this case, the update information is written at a position apart from the position where the corresponding updated information is recorded.

[0005]

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

It is an object of the present invention to provide an optical disc device capable of recording update information at a position physically close to updated information and improving access performance.

[0007]

In order to achieve the above object, the present invention is an optical disc apparatus using an optical disc having two layers for recording information, wherein one information recording layer of the optical disc is a read-only layer. , When the other information recording layer is used as a read / write layer and the information recorded in the one information recording layer is updated, the update information is updated at a position physically close to the updated information in the other information recording layer. When reading information from the optical disc and the means for recording, if the information to be read is not updated, the information recorded in one of the information recording layers is read and the information to be read is updated. In this case, a means for reading the update information recorded on the other information recording layer is provided.

By thus recording the update information and the updated information in different information recording layers, it becomes possible to record the update information in the same position as the updated information. Further, even when the update information cannot be recorded at the same position as the updated information, it is possible to record it at a very close position. Therefore, when the information recorded on the optical disc is read, the update information can be read at the same position as or the position close to the information to be updated, so that the continuity of the information recorded on the optical disc can be maintained and the access characteristic Is improved.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to the drawings. FIG. 3 shows a schematic configuration of the optical disk device. As the optical disc 1, one having two information recording layers 2 and 3 is used. In the following description, the lower information recording layer 2 will be referred to as the first layer, and the upper information recording layer 3 will be referred to as the second layer.

In the optical disc 1 of this example, the second layer 3
Is a read-only layer in 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 changes in roads, road regulations, etc., update data A ′ is written in the first layer 2. The update data A ′ is written at the physically same position immediately below the corresponding updated data A. If the data cannot be written in the same position, the update data A ′ is written in a position close to the updated data A.

Further, the first layer 2 also records information regarding the update of the written update data A '. The information regarding this 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 ′.
Contains relevant information about. An optical head 4 facing the first layer 2 and the second layer 3 for reading and writing data.
Is provided. The optical head 4 reads the data recorded on the second layer 3 by focusing on the second layer 3. Further, the optical head 4 reads the update data recorded in the first layer 2 or writes the update data by focusing on the first layer 2.

The optical head 4 is movable in the radial direction of the optical disc 1 by a 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 is composed of 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 relating to data update performed in the past is read from the first layer 2 of the optical disc 1 and stored in the memory. In step S2, the physical position of the data A to be updated on the second layer 3 is calculated. In step S3, it is determined whether or not the update data A'can be written in the first layer 2 at the same position as the physical position calculated in step S2. As an example of the case where writing is impossible, there is a case where other update data has already been recorded within the range where the update data A ′ is to be written.

If it is determined in step S3 that writing is not possible, the process proceeds to step S4, and the area in which the update data can be written is located at a position close to the physical position calculated in step S2. Look on layer 2. Step S5
Then, the optical head 4 is moved to the physical position calculated in step S2 or the writable area found in step S4, and the update data is written to the address.

In step S6, information about the update of the data updated this time is stored in the memory. As described above, the information regarding this update includes the updated data A that has been updated.
Address, a recording address of update data, and related information of both. Further, the information regarding 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 reading data.
In step S11, the file address information is read from the optical disc 1 and stored in the memory. In step S12, the information regarding the data update is read from the optical disc 1 and stored in the memory.

In step S13, the process waits until an access request is issued, and when the access request is issued, step S13.
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 regarding the update of the data. If the data has not been updated, the process proceeds to step S16 to read the data of the second layer 3. Therefore, for the data that has not been updated, the data is read out immediately after accessing the address.

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

In step S19, it is judged whether or not the reading of the requested data is completed, and the process returns to step S15 and the data reading is continued until the reading is completed. When the reading of the requested data is completed, the process returns to step S13, and the standby is continued until the next access request is issued. As is clear from the above description, since the update data A is recorded at the same position as or near the update target data A ′, the data continuity can be maintained and the access performance can be prevented from deteriorating. .

[0020]

As described above, 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 the operation of the optical disk device of FIG. 1 when updating data.

FIG. 3 is a flowchart showing an operation at the time of reading data of the optical disc device of FIG.

[Explanation of symbols]

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

Claims (1)

[Claims] 1. An optical disc apparatus using an optical disc having two layers for recording information, wherein one information recording layer of the optical disc is a read-only layer and the other information recording layer is a read / write layer. , When updating the information recorded on the one information recording layer, means for recording the update information at a position physically close to the updated information on the other information recording layer, and reading the information from the optical disc , When the information to be read is not updated, the information recorded in the one information recording layer is read, and when the information to be read is updated, the other information recording layer is read. An optical disk device comprising: means for reading the recorded update information.