Abstract:
A method of updating disc information of an optical disc includes checking whether a file system bitmap in a user data area of the optical disc had been updated, and updating disc information in a lead in area of the optical disc when the file system bitmap had been updated. By choosing an appropriate updating timing of the disc information, the present invention can reduce the risks of accidents such as power break down or abnormal host behavior occurring before the disc information is updated completely, and can prevent frequent access of locations storing the disc information. 
     Besides one method to choose the appropriate updating timing of disc information is introduced in this invention, one method to recover the bitmap of disc information is also introduced if the optical disc has bitmap table and bitmap table is defective.

Description:
BACKGROUND  
       [0001]    The present invention relates to an optical system, and more particularly, to a method of updating disc information of an optical disc. 
         [0002]    An optical rewritable/recordable disc contains a lead-in area, followed by a user data area. Recording disc information (for example, the defect table, track information, bitmap, and etc.) is stored in the lead-in area for the disc drive to get current data layout and usage status. 
         [0003]    Conventionally, disc information is temporarily stored and accumulated in a DRAM inside the disc drive. After a specific time period, the accumulative disc information is written into the lead-in area to update disc information in lead-in area. However, when the specific time period is too long, there is a greater risk that accidents (e.g. power break down or abnormal host behavior) will occur during the specific time period, and the disc information stored in the lead-in area may not be updated with the latest disc information, resulting in errors when the optical rewritable/recordable disc is accessed later. On the other hand, when the specific time period is too short, the region storing the disc information in the lead-in area of the rewritable/recordable disc will be updated frequently, so this region will break quickly or be exhausted due to over consumption, and the disc drive will not allow the host to record the rewritable disc again because no space to update the disc information and that can&#39;t represent the usage of user data. Therefore, selecting proper timing for updating disc information is an important issue. 
       SUMMARY  
       [0004]    One objective of the present invention is therefore to provide a method of updating disc information of an optical disc in order to solve the above problems. 
         [0005]    Another objective of the present invention is to provide a method of updating disc information of an optical disc to reconstruct bitmap information of the optical disc if lead-in area of this disc has bitmap table and bitmap table is defective. 
         [0006]    According to an exemplary embodiment of the present invention, a method of updating disc information of an optical disc is disclosed. The method comprises checking if a file system bitmap in a user data area of the optical disc is updated, and updating disc information in a lead-in area of the optical disc when the file system bitmap is updated. 
         [0007]    According to another exemplary embodiment of the present invention, a method of updating disc information of an optical disc is disclosed. The method comprises checking if a write command is used to update a file system bitmap in a user data area of the optical disc, and updating disc information in a lead-in area of the optical disc when the write command is used to update the file system bitmap. 
         [0008]    According to another exemplary embodiment of the present invention, a method of recovering the bitmap table of disc information of an optical disc is disclosed. The method comprises checking if a bitmap in a lead-in area of the optical disc is defective, and recovering and updating disc information of the bitmap in the lead-in area of the optical disc according to contents of a file system bitmap in a user data area of the optical disc. 
         [0009]    These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0010]      FIG. 1  is a diagram showing a lead-in area, a user data area and a lead-out area contained in an optical rewritable/recordable disc. 
           [0011]      FIG. 2  is a flowchart showing the process of updating disc information according to the timing when the area of a file system bitmap is updated according to one exemplary embodiment of the present invention. 
           [0012]      FIG. 3  is a flowchart showing the process of updating disc information according to the timing when the host sends a write command that is used to update a file system bitmap area according to one exemplary embodiment of the present invention. 
           [0013]      FIG. 4  is a diagram showing a lead-in area, a user data area and a lead-out area contained in a BD-R disc. 
           [0014]      FIG. 5  is a flowchart showing a process of bitmap information recovery according to an exemplary embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION  
       [0015]    Certain terms are used throughout the description and following claims to refer to particular components. As one skilled in the art will appreciate, manufacturers may refer to a component by different names. This document does not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms “include” and “comprise” are used in an open-ended fashion, and thus should be interpreted to mean “include, but not limited to . . . ”. 
         [0016]    In order to better update disc information stored in a non-user-data area (e.g. a lead-in area) of an optical rewritable/recordable disc, the present invention proposes a novel updating timing for the disc drive to write the accumulative disc information. The optical rewritable/recordable disc (i.e. optical rewritable disc or optical recordable disc) herein includes but is not limited to a Blu-ray recordable disc (BD-R), a Compact Disc-Rewritable (CD-RW), a Digital Versatile Disc-Rewritable (DVD-RW), a DVD+RW, a DVD-Random Access Memory (RAM), a BD-RE, and a High Definition (HD)-DVD-RW. The disc information updating therefore includes updating the recording management area (RMA) of the DVD-RW/HD-DVD-RW, the formatting disc control block (FDCB) of the DVD+RW, the defect management area (DMA) of the DVD-RAM/BD-RE and the temporary disc management area (TDMA) of the BD-R disc. 
         [0017]    As shown in  FIG. 1 , a rewritable/recordable disc contains a lead-in area and a user data area, and disc information  10  recording current utilization status of the optical rewritable/recordable disc is established in the lead-in area by the disc drive. The disc drive, in one embodiment, updates the disc information  10  according to the timing when the host updates the file system bitmap  12  in the user data area. In this way, the updating of the disc information  10  and the file system bitmap  12  are synchronized, and the risks of accidents such as power break down or abnormal host behavior occurring before the disc information  10  is updated completely can be decreased, while over-consumption of the locations that store the disc information  10  resulting from frequent recording can be avoided. 
         [0018]    Please refer to  FIG. 2 , which is a flowchart showing the process of updating the disc information  10  according to the timing when the host updates the file system bitmap  12  according to an exemplary embodiment of the present invention. At first, when the disc drive has detected that the loaded disc is a rewritable/recordable disc, it detects address range of the file system bitmap  12  in the optical rewritable/recordable disc in step  210 . The updating of file system bitmap  12  is essentially managed by the host, and has a fixed address after initialization. The logic address is recorded in the volume of the optical rewritable/recordable disc, and fields contained in the volume are fully specified by the file system specification of the optical rewritable/recordable disc. Step  210  can be performed during a start-up procedure of the disc drive into which the optical rewritable/recordable disc is loaded or standby time when the user data area of the rewritable disc is not accessed after the start-up procedure. 
         [0019]    The disc drive then detects whether the user data area is recorded by the host (step  220 ). Since the address range of the file system bitmap  12  has been found, the disc drive can further check whether the recording is to update the file system bitmap  12  in the user data area (step  220 ). When the detection result is yes, i.e. the file system bitmap  12  is updated; the disc drive updates the disc information  10  in the lead-in area correspondingly (step  240 ). The flow chart then goes to step  250  to end this update, and may return to step  220  to detect the recording of the user data area again. 
         [0020]    Generally speaking, updating the user data area is processing after getting a write command from the host. However, the updating of user data area will be fail sometimes even with getting the write command from the host. Thus, the previous embodiment can be taken as a situation that the disk information is updated when confirming the user data area is updated successfully. 
         [0021]    In another embodiment, as shown in the flow chart of  FIG. 3 , the disc drive detects a predetermined command sent by the host in order to detect the update of the file system bitmap  12  (Step  320 ). The disc drive determines whether a received write command is a specific write command specified for updating the file system bitmap  12  by comparing a write address associated with the received write command and the address of the file system bitmap  12  found in the start step (Step  330 ). After receiving the specific write command, the disc drive updates the disc information  10  by overwriting or appending the latest disc information to the disc information  10 , depending on the specification of the rewritable disc (Step  340 ). The flow chart then goes to step  350  to end this update, and may return to step  320  to detect the receiving of the write command again. 
         [0022]    The updating of the disc information  10  can be performed after performing the specific write command to update the file system bitmap  12  in the user data area, or after receiving the specific write command and before performing the specific write command to update the file system bitmap  12 . That is, the disc information  10  can be updated before the updating of the file system bitmap  12 , and vice versa. 
         [0023]    The present invention is not limited to detect a write command relating to the file system bitmap  12 . In another embodiment, the command detected in Step  320  is a control command sent by the host for controlling the disc drive to update the disc information  10 . The control command may not be a standard ATA/ATAPI command, but a random command that the host negotiates with the disc drive in advance. Please note that Step  310  of reading the logic address specification can be omitted in this embodiment since the address of the file system bitmap  12  is not required in the updating process. 
         [0024]    As well as updating the disc information of the rewritable/recordable disc, the present invention further provides a method for recovering defect bitmap of disc information of the rewritable/recordable disc. A BD-R disc with RRM is taken as an example. 
         [0025]    Please refer to  FIG. 4 . A BD-R disc comprises a lead-in area and a user data area following to the lead-in area, wherein the lead-in area records a bitmap  40  updated by the disc drive and the user data area records a bitmap  42  updated by the host respectively. When the disc drive finds that the bitmap  40  recording non-blank positions of the BD-R disc is defective, the drive repairs the bitmap  40  according to the file system bitmap  42  stored in the user data area. Please refer to  FIG. 5 , which is a flowchart showing a process of bitmap information recovery according to an exemplary embodiment of the present invention. In order to utilize contents of the file system bitmap  42 , the drive detect an address of the file system bitmap  42  in Step  510  according the file system specification. Since detect a logic address of file system bitmap has been introduced before (in Steps  210  and  310 ), a detailed description is omitted here for brevity. 
         [0026]    The disc drive then checks if the bitmap  40  in the lead-in area is defective in step  520 . If the bitmap  40  is found to be defective, the disc drive reads the data of the bitmap  42  according to the address found in step  510 , and recovers the bitmap  40  by referencing the file system bitmap  42  in the user data area (step  530 ). 
         [0027]    One embodiment of step  530  is detailed in the following. The contents of the file system bitmap  42  are transformed to conform to a format of the bitmap  40  stored in the lead-in area because units adopted in the bitmap  40  and the file system bitmap  42  may be different. Each bit in the bitmap  40  represents the status of one ECC block of the BD-R disc, while each bit in the file system bitmap  42  represents the status of one sector of the BD-R disc. The disc drive may further decode the file system bitmap  42  in order to examine the reliability of the file system bitmap  42 . When the contents of the file system bitmap are decodable (i.e. reliable), the disc drive then updates the disc information in the bitmap  40  according to the transformed contents of the file system bitmap  42 . In one embodiment, the transformed contents are appended to the defect disc information in the bitmap  40  (the transformed contents are written in the next sector of the defect disc information), and a disc definition structure (DDS) changes to point to the address of the appended transformed contents rather than the address of the defect disc information. The bitmap  40  is therefore updated, and the drive can correctly analyze disc information of the BD-R disc to avoid overwriting the BD-R disc. By recovering the bitmap  40  according to the contents of the file system bitmap  42 , the present invention therefore resolves the problem of the user data area not being allowed to be further written to when the bitmap  40  is found to be defective. 
         [0028]    Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention.