KR100614965B1 - High Speed Buffering Method using Defect management for Optical Disc Drive - Google Patents

Abstract

The present invention relates to a fast buffering method for an optical disk drive using a defect management method, the method comprising: searching for a defect management area in an optical disc and searching for a defect area existing in a user area in advance; Decoding and buffering data existing in the user area until the defective area exists; Adjusting a buffering pointer when a defective area exists; Searching and decoding data recorded in the spare area when the decoding and buffering for the user area is completed and buffering the adjusted buffering pointer.

DVD, RAM, RW, Buffer, Spare Area

Description

High Speed Buffering Method using Defect management for Optical Disc Drive

1 is a view showing a data area of a general optical disc.

2 is a diagram illustrating a general SDL entry structure.

3A illustrates a general sleeping alternative method.

3b illustrates a general linear replacement method.

4A is a diagram illustrating a state in which data is recorded by a linear replacement method or a skipping method when using SDL in a general optical disc.

4B to 4D are diagrams showing an example in which information of a defective block generated at the time of recording by the linear replacement method is de-locked to the SDL entry.

5 is a diagram illustrating a buffering sequence in an optical disk in which a defective area exists.

6 is a diagram showing the basic structure of a general buffer.

7 illustrates a general disk buffering method.

8 is a diagram illustrating a basic buffering method of a DVD-RAM.

9 is a diagram illustrating a buffering method according to an embodiment of the present invention.

10 is a flowchart illustrating a buffering method according to an embodiment of the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fast buffering method of an optical disc drive using a defect management method, and more particularly, to a disc using a defect management method (DM) (especially a DVD-RAM / DVD + RW). A fast buffering method.

In general, optical recording media are classified into three types, such as read-only ROM, write-once worm type, and rewritable rewritable type. Lose.

The ROM type optical recording medium may include a compact disc read only memory (CD-ROM) and a digital versatile disc read only memory (DVD-ROM), and a worm type optical recording medium may be written once. Recordable Compact Discs (CD-Rs) and Recordable Digital Versatile Discs (DVD-Rs).

In addition, freely and repeatedly rewritable discs include a rewritable compact disc (CD-RW) and a rewritable digital versatile disc (DVD-RW).

On the other hand, in the case of a rewritable optical recording medium, the recording / reproducing operation of information is repeatedly performed due to the use characteristics thereof, so that the mixing ratio of the mixture constituting the recording layer formed for recording information on the optical recording medium is initially mixed. It is different from the ratio and loses its characteristics, resulting in an error in recording / reproducing information.

This phenomenon is called deterioration, and the deteriorated area appears as a defect area when the format, recording, and reproducing command of the optical recording medium is executed.

In addition to the deterioration phenomenon, defect areas of the rewritable optical recording medium may be generated due to scratches on the surface, dust such as dust, errors in production, and the like.

Therefore, in order to prevent data from being recorded / reproduced in the defect area formed due to the above reasons, it is necessary to manage the defect area.

To this end, as shown in FIG. 1, a defect management area (hereinafter referred to as DMA) is provided in a lead-in area and a lead-out area of the optical recording medium. The defect area of the optical recording medium is managed. In addition, the user area in which actual data is recorded has a separate spare area for use when a defect occurs.

In general, four DMAs exist in one disk, two DMAs exist in the lead-in area, and the other two DMAs exist in the lead-out area.

Here, each DMA is composed of two blocks, and has a total of 32 sectors. The first block (called a DDS / PDL block) of each DMA includes a Disc Definition Structure (DDS) and a Primary Defect List (PDL), and the second block (called an SDL block) of each DMA is an SDL (Secondary). Defect List).

In this case, PDL means main defect data storage, and SDL means defect data storage.

In general, the PDL contains entries of defective sectors generated during the disc creation process and all the defective sectors identified during disc formatting, that is, initial formatting and re-initialization. It is stored in sector units. Here, each entry is composed of an entry type and a sector number corresponding to a defective sector.

On the other hand, the defect data storage unit SDL lists defect information in units of blocks, and stores entries of defect regions occurring after the format or defect regions that cannot be stored in the PDL during the format. Each SDL entry includes an area for storing the sector number of the first sector of the block in which the defective sector has occurred, an area for storing the sector number of the first sector of the replacement block to replace it, and an unused area (as shown in FIG. Reserved). In addition, one bit is allocated to each SDL entry for Forced Reassignment Marking (FRM). If the value is 0b, the replacement block is allocated and there is no defect in the replacement block. , 1b means that no replacement block is allocated or the allocated replacement block is defective.

Therefore, defective areas (i.e., defective sectors or defective blocks) in the data area are replaced with normal areas, which are usually a slipping replacement method and a linear replacement method.

The sleeping replacement method is applied when the defective area is registered in the main defect data storage unit (PDL). As shown in FIG. 3A, the sleeping replacement method is listed in the PDL in a user area in which actual data is recorded. If a defective sector is present, the defective sector is skipped and replaced with the normal sector following the defective sector to record data. Therefore, the user area in which data is recorded occupies a spare area as much as the defective sector skipped and eventually skipped. In addition, the linear replacement method is applied when the defective area is registered in the defective data storage unit SDL, and as shown in FIG. 3B, the defective data storage unit SDL is located in the user area or the spare area. If a defect block listed in Fig. 1 exists, it is replaced with a replacement area in units of blocks allocated to the spare area to record data. At this time, the physical sector number (PSN) assigned to the defective block remains as it is, but the logical sector number (LSN) moves together with the data to the replacement block. This linear replacement method is effective when reading or writing data that does not require real time. The data that does not require the real time is hereinafter referred to as PC-data for convenience of explanation, as in FIG. 4A.

If a replacement block written to the defective data storage SDL is later found to be defective, a direct pointer method is applied to the defective data storage SDL registration. That is, by the direct pointer method, the defective replacement block is replaced with a new replacement block, and the SDL entry in which the defective replacement block is registered is modified with the sector number of the first sector of the newly replaced replacement block.

4A illustrates a process of recording data in the user area or reproducing the recorded data, when the defective block listed in the defective data storage unit SDL is replaced with a replacement block and recorded. 4d shows examples of SDL entries that can be generated by the linear replacement method, and sequentially shows the FRM, the first sector number of the defective block, and the first sector number of the replacement block. That is, if (1, blkA, 0) is found as shown in FIG. 4B, a defective block blkA is found, but the defect is fatal and no replacement block is allocated, and as shown in FIG. 4C, (0, blkA, blkE). Means that the replacement block blkE without defect is allocated and data to be written in the defect block blkA of the user area is replaced with the replacement block blkE of the spare area. In addition, as shown in FIG. 4D, (1, blkA, blkE) indicates a case where a defect occurs in the replacement block blkE of the spare area in which the defective block blkA of the user area is replaced, and in this case, a new method is used by the direct pointer method. Replacement blocks are allocated.

The disk defect area management method as described above should read the combined management area (DMA) once the disk using the defect management method comes in to find out where the defect is and where it is replaced.

If the block is registered in a defect management area defect entry based on the information of the defect management area, the buffering is stopped, the search is performed to the corresponding spare area, decoding is started, and buffering is performed.

When buffering of the spare area is completed, the search is performed again to the original position, and then decoding is started to perform buffering.

This series of buffering procedures is shown in FIG. Referring to FIG. 5, when the buffering process is performed, after buffering is performed from the first block to the second block, if a defect area is found, the buffering is stopped and the spare area is searched and buffered. When buffering of the spare area is completed, the user area is searched and buffered again. That is, 1 block buffering → 2 block buffering → buffering stop → 3 'block search → 3' block buffering → buffering stop → 4 block search → 4 block buffering → 5 block buffering.

However, in this method, in the case of a defective disk, this process is repeated to continuously search between the newer data area and the spare area. As a result, the frequent seeks delay the buffering time. In particular, the spare area is located at the outermost or innermost periphery of the disk, which can cause the servo to become unstable due to frequent searching, which may cause problems in system stability.

Disclosure of Invention An object of the present invention is to provide a method for faster buffering of a disk using a defect management scheme, which has been devised to solve the above problems.

A high speed buffering method for an optical disk drive using the defect management method of the present invention comprises the steps of: searching for a defect area existing in a user area in advance by searching for a disk defect management area in the optical disc; Decoding and buffering data existing in the user area until the defective area exists; Adjusting a buffering pointer when a defective area exists; Searching and decoding data recorded in the spare area when the decoding and buffering for the user area is ended, and buffering the adjusted buffering pointer.

In the present invention, when the defective area is found in the user area, it is preferable to store the data in the next block by increasing the value of the pointer currently buffered by +1.

In the present invention, when a defective area is found, the current buffering pointer is preferably stored in an arbitrary pointer.

In the present invention, the search for the spare area is preferably performed from the first address.

In the present invention, it is preferable that an address stored in the arbitrary pointer is used as an address for searching the spare area to find data and buffering the spare area.

In the present invention, it is preferable that the end of buffering for the user area occurs when the data is completely filled in the buffer.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. In adding reference numerals to components of the following drawings, it is determined that the same components have the same reference numerals as much as possible even if displayed on different drawings, and it is determined that they may unnecessarily obscure the subject matter of the present invention. Detailed descriptions of well-known functions and configurations will be omitted.

6 is a diagram illustrating a general structure of a buffer.

In the above embodiment, the buffer has a parameter area and N buffer areas.

The above embodiment schematically illustrates how data is stored on a buffer.

Referring to FIG. 6, the parameter area includes information about a drive such as disc information, inquiry information, and identification information, and data having actual information is stored in a buffer area.

To buffer, first locate the data you want to buffer and start decoding. After decoding of the first block is completed, data is stored in the 0th buffer area. When the next decoding is completed, the next data is stored in the buffer area 1. This buffering continues until the buffer is saturated. That is, it keeps storing in this manner and stops decoding when it reaches the Nth buffer area.

7 is a diagram illustrating a buffering method of an optical disk in general.

In this embodiment, the optical disk includes the first to fourth blocks from the inner circumference to the outer circumference and the optical disk drive retrieves the data in the optical disk from the inner circumference to the outer circumference. Therefore, the data blocks are sequentially read from 1 to 4, and the read data are sequentially stored from the 0th buffer, which is the initial address of the buffer area.

8 is a diagram illustrating a general buffering method of an optical disk drive using a defect area management method.

Referring to FIG. 8, in the optical disk, a first spare area and a second spare area exist outside the user data area. The optical disk drive retrieves data from the user data area and buffers it smoothly. If the defective area is found after the buffering continues, the data of the spare area recorded instead of the defective area is searched and buffered, and then the data recorded after the defective area is sequentially buffered.

9 is a diagram illustrating a buffering method according to an embodiment of the present invention.

In the case of an optical disc using the defect area management method (in the present invention, 'DVD-RAM' is taken as an example), since a defect may occur, several search operations are performed during buffering. In other words, once you get to the defective part, stop buffering, go to the spare area, perform the buffering, and come back to the original position. That is, the search operation is performed as many as the number of defects * 2.

In the present invention, however, the pointer is adjusted in the buffer to perform sequential buffering without performing a search.

Referring to the process according to the present invention, if a defect is encountered during buffering, the buffer pointer is increased by +1 and the corresponding block is skipped to continue buffering the next data. The original buffer pointer is held as a pointer for future reference when buffering the spare area. After the buffer is saturated, the search starts in the spare area, replaces the buffering pointer with the original pointer, decodes the skipped part (replacement part), and stores it in the original buffer pointer. Only one search is needed until buffering is complete. Details of this are shown in FIG. 9. Referring to FIG. 9, the buffering order is similar to the conventional one. According to the existing buffering method, the search is performed four times, but according to the present invention, the buffering can be performed only once.

Details of the above-described method will be described with reference to FIG. 10.

10 is a flowchart illustrating a buffering method according to an embodiment of the present invention.

Step 1001 is a process of inspecting a defect management area block, in which a start address of a defect area in a user area and a data address in a spare area in which data not recorded due to occurrence of the defect area have been recorded instead. In advance, the structure on the user data is grasped in advance.

Step 1002 is a process of starting decoding, where data contained in the user data is read by optical pickup by servo driving to decode the data.

Step 1003 is a process of finding a defective area on the user data, and the optical disk drive sequentially decodes and sequentially buffers the data until the defective area is found in the user data.

Step 1005 is a process of adjusting the buffer pointer. If a defective block is encountered while decoding the data recorded in the user data as described above, the buffer pointer is increased by +1 and the data of the next block is decoded and buffered. The original buffer pointer, i.e., the address in the buffer where the current defective block should be buffered, is preferably stored in an arbitrary pointer (defined herein as a P pointer). The P pointer is defined as many as the number of defects.

Steps 1001 to 1005 continue until the buffer is saturated. When data is saturated in the buffer, the optical pickup starts searching for the spare area. That is, when the buffer for the user data is saturated, decoding of the user data is stopped and the inspection of the spare area is started. If data to be stored in the defective area of the user data is retrieved after the spare area is examined, the buffer pointer is adjusted to the corresponding pointer. If a buffer pointer for the data is defined, the data is decoded and the decoded data is stored in the buffer. The above process is repeated until all the data recorded in the spare area is stored in the corresponding buffer. When all addresses of the buffer are full, the above process is completed.

As described above, it has been described with reference to the preferred embodiment of the present invention, but those skilled in the art various modifications and changes of the present invention without departing from the spirit and scope of the present invention described in the claims below I can understand that you can.

As described above, according to the present invention, there is an effect of enabling faster and more stable buffering by adjusting the buffer pointer instead of performing several search operations during buffering.                     

In addition, the present invention can increase the stability of the system due to the unnecessary search operation when there are many defects, that is, when a large number of searches are required.

Claims (6)

In the disk buffering method of the optical disk drive, Retrieving a defect area existing in the user area by searching the disk defect management area in the optical disc; Decoding and buffering data existing in the user area until the defective area exists; Adjusting a buffering pointer when a defective area exists; And retrieving and decoding data recorded in the spare area and buffering the buffered data with the adjusted buffering pointer when the decoding and the buffering for the user area are ended. 2. The high speed buffering of an optical disk drive using a defect management method as claimed in claim 1, wherein when a defective area is found in the user area, data is stored in a next block by increasing the value of the currently buffered pointer by +1. Way. 3. The high speed buffering method of claim 2, wherein the current buffering pointer is stored in an arbitrary pointer when a defective area is found. 4. The high speed buffering method of claim 3, wherein the search for the spare area is performed from an initial address. 5. The high speed buffering method of claim 4, wherein an address stored in the random pointer is used as an address for searching the spare area to find data and buffering the data. 2. The high speed buffering method of an optical disc drive using a defect management method according to claim 1, wherein the end of buffering for the user area occurs when the data is completely filled in the buffer.

Images