1. Field of the Invention
The invention relates to optical disks, and more particularly to disk management data of optical disks.
2. Description of the Related Art
Before an optical disk drive accesses an optical disk loaded therein, the optical disk drive must know how data was stored on the optical disk. For example, the optical disk drive knows starting addresses of all sectors of the optical disk, thereby searching the sectors for a target address accessed by a host. Such data layout information is stored on a specific area of an optical disk and read as a guide for all subsequent access operations of the optical disk drive.
Each type of optical disk has a specific data structure format for recording the aforementioned data layout information. In addition, whenever an optical disk is written with new data, the data layout information may be updated to reflect the latest data layout pattern. Because slight data layout information errors may lead to serious optical disk drive access operation malfunctions, the data layout information should be errorless, accessing the data layout information is crucial for an optical disk.
To ensure accuracy of the data layout information, the data layout information is often duplicated to obtain multiple copies stored on different portions of an optical disk. Thus, when a copied data layout information is not available due to defects such as disk surface scratches, the optical disk drive can still access the data layout information via the other copies. For example, a rewritable blu-ray disk (BD-RE) has four data management (DMA) zones for respectively storing a copy of the data layout information, and each copy is referred to as a data management structure (DMS). In addition, a rewritable digital versatile disk (DVD-RW) has multiple recording management zones (RMZ) for respectively storing a copy of the data layout information, wherein each copy is referred to as recording management data (RMD). Note that the copies of the data layout information are referred to as disk management data copies in the specification.
Referring to
When an optical disk drive requires data layout information such as a disk definition structure and a defect list of a blu-ray disk, the optical disk drive must read all four data management zones DMA1, DMA2, DMA3, and DMA4. Referring to
The conventional method 200 shown in
The invention provides a method for reading disk management data of an optical disk. In one embodiment, the disk management data comprises data layout information of the optical disk, and a plurality of disk management data copies of the disk management data are storied on the optical disk. First, a first disk management data copy selected from the plurality of disk management data copies is read from the optical disk. An accuracy measure of the first disk management data copy is then calculated to determine whether the accuracy measure of the first disk management data copy is acceptable. When the accuracy measure of the first disk management data copy is acceptable, the optical disk is accessed according to the first disk management data copy.
The invention provides another method for reading disk management data of an optical disk. In one embodiment, the disk management data comprises data layout information of the optical disk, and a plurality of disk management data copies of the disk management data are storied on the optical disk. First, a first disk management data copy selected from the plurality of disk management data copies is read from the optical disk. A second disk management data copy selected from the plurality of disk management data copies is then read from the optical disk. The first disk management data copy is compared with the second disk management data copy to determine whether data of the first disk management data copy and the second disk management data copy are identical. When data of the first disk management data copy and the second data copy are identical, the optical disk is accessed according to the first disk management data copy or the second data copy.
The invention also provides an optical disk drive. In one embodiment, the optical disk drive accesses an optical disk, wherein a plurality of disk management data copies of disk management data of the optical disk are storied on the optical disk, and the disk management data comprises data layout information of the optical disk. In one embodiment, the optical disk drive comprises a pickup head and a controller. The pickup head reads a first disk management data copy selected from the plurality of disk management data copies from the optical disk. The controller calculates an accuracy measure of the first disk management data copy, determines whether the accuracy measure of the first disk management data copy is acceptable, and controls the pickup head to access the optical disk according to the first disk management data copy when the accuracy measure of the first disk management data copy is acceptable.
A detailed description is given in the following embodiments with reference to the accompanying drawings.
The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:
The following description is of the best-contemplated mode of carrying out the invention. This description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. The scope of the invention is best determined by reference to the appended claims.
Referring to
The optical disk drive 300 accesses the optical disk 306 according to data layout information of the optical disk 306, such as starting addresses and ending addresses of sectors of the optical disk 306. The optical disk drive 300 therefore may retrieve the data layout information of the optical disk 306 before the optical disk 306 is further accessed. Disk management data comprising the data layout information is duplicated into multiple disk management data copies respectively stored on different portions of the optical disk 306. When the optical disk 306 is a rewritable blu-ray (BD-RE) disk, the disk management data copies refer to the data management structures (DMS) of the rewritable blu-ray disk. When the optical disk 306 is a rewritable digital versatile (DVD-RW) disk, the disk management data copies refer to the recording management data (RMD) of the rewritable digital versatile disk. The optical disk drive 300 therefore reads the disk management data copies to obtain the data layout information of the optical disk 306.
Referring to
After the target disk management data is obtained, a decision circuit 308 of the controller 304 then calculates an accuracy measure of the target disk management data (step 404). The accuracy measure is one kind of disc quality measure method such as error rate. In one embodiment, the accuracy measure is an error rate determined according to an error correction code (ECC) of the first disk management data copy. In another embodiment, the accuracy measure is an error detection code (EDC) check of the first disk management data copy. However, there may be other accuracy measures according to different applications. The decision circuit 308 of the controller 304 then determines whether the accuracy measure of the target disk management data is acceptable (step 406). For example, when the accuracy measure is an EDC check, the decision circuit 308 checks whether the EDC is correct. When the accuracy measure is an error rate, the decision circuit 308 compares the error rate with a threshold. If the error rate is smaller than the threshold, the target disk management data is acceptable.
When the target disk management data is determined to be acceptable at step 406, the target disk management data is considered to comprise correct data layout information. The controller 304 then accesses the optical disk 306 according to the target disk management data without reading the other disk management data copies (step 408). Though the other disk management data copies are not read when accessing the optical disk 306 according to the target disk management data in this embodiment, they may still be read to facilitate the accessing based on different applications. Thus, compared to the conventional method 200, the optical disk drive 300 does not need to read all disk management data copies of the optical disk 206, and a delayed time period due to reading of the disk management data is reduced, thereby improving performance of the optical disk drive 300. When the target disk management data is determined to be not acceptable at step 406, the controller 304 directs the pickup head 302 to read another disk management data copy from the optical disk to obtain a new target disk management data (step 410). The accuracy measure of the new target disk management data is then calculated at step 404 to determine whether the new target disk management data is acceptable. If so, the controller 304 then accesses the optical disk 306 according to the new target disk management data without reading the other disk management data copies (step 408). Though the other disk management data copies are not read when accessing the optical disk 306 according to the new target disk management data in this embodiment, they may still be read to facilitate the accessing based on different applications.
According to method 400 of
After the first disk management data copy and the second disk management data copy are obtained, a decision circuit 308 of the controller 304 compares read disk management data copies including the first disk management data copy and the second disk management data copy (step 506). If any two of the read disk management data copies are identical at step 508, the two identical disk management data copies are believed to comprise correct data layout information. The controller 304 then accesses the optical disk 306 according to the identical ones of the read disk management data copies without reading the other disk management data copies (step 510). Though the other disk management data copies are not read when accessing the optical disk 306 according to the identical ones of the read disk management data copies in this embodiment, they may still be read to facilitate the accessing based on different applications. Thus, compared to the conventional method 200, the optical disk drive 300 does not need to read all disk management data copies of the optical disk 206, and a delayed time period due to reading of the disk management data is reduced, thereby improving performance of the optical disk drive 300. When any two of the read disk management data copies are not identical at step 508, the controller 304 directs the pickup head 302 to read another disk management data copy from the optical disk (step 512). The loop of steps 512, 506, and 508 will continue until two identical disk management data copies are found. If so, the controller 304 then accesses the optical disk 306 according to the two identical disk management data copies without reading the other disk management data copies (step 510). Though the other disk management data copies are not read when accessing the optical disk 306 according to the two identical disk management data copies in this embodiment, they may still be read to facilitate the accessing based on different applications.
The invention provides a method for reading disk management data copies of an optical disk. To determine data layout information of the optical disk, not all of the multiple disk management data copies stored on the optical disk are read. An optical disk drive then accesses the optical disk according to the data layout information. A delay time due to reading of the disk management data copies is therefore reduced, thus improving performance of the optical disk drive.
While the invention has been described by way of example and in terms of preferred embodiment, it is to be understood that the invention is not limited thereto. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.