KR19990075795A - Optical disc - Google Patents

Abstract

The present invention relates to an optical disc having a defect management area that can cope with an optical disc of recordable large capacity.

The optical disc of the present invention includes information on a defect block consisting of the number of the Nth zone and the position number of the defective block in the Nth zone, the number of the zone containing the replacement block corresponding to the defective block, and the replacement block in the zone. And a defect management area in which a defect area list including information of a replacement block composed of a position number is recorded.

According to the present invention, by reducing the size of the recording unit of the SDL recorded in the defect management area, more defect blocks can be managed by the defect management area of a limited size.

Description

Optical Disc

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc, and more particularly, to an optical disc having a defect management area that can correspond to a recordable large capacity optical disc.

Optical discs are a disc medium that has begun to be generalized with the spread of compact discs (CDs). In recent years, optical discs (Digital Versatile Disc) have become more and more expected. In general, optical discs are discs for reproduction only, such as CD-ROM (CD-Read Only Memory), DVD-ROM, etc., and once-recordable discs such as CD-WORM (CD-WORM Once) In addition, it can be classified as a disc capable of repeating recording, such as a CD-RW (CD-Rewritable), a DVD-Random Access Memory (DVD-RAM), or the like. Here, studies have been actively conducted to increase the capacity of DVD-RAM (DVD-Random Access Memory) among repeatable recording discs due to the proposal of the standard.

However, recordable discs have a defective area due to deterioration of the recording surface due to repetitive recording, scratches, errors in production and fineness. Since data is not recorded correctly in such a defective area, accurate data cannot be obtained during reproduction. In other words, the defective area degrades the reliability, which is an important factor of the disc. In order to prevent deterioration of the reliability of this disk, data must be controlled so that data is not recorded in the defective area.

To this end, the disk driver detects a defective area by recording test data before recording information on the disk and then reproducing the same to verify whether a signal of a reference level or higher is detected. In order to effectively manage the detected defective areas, a list of addresses of the defective areas is recorded in a specific area of the disc, and the data is not recorded in the corresponding defective areas by reading the defective area list in the next recording operation. Do not The defect area list is also used in the reproduction operation.

The defect area list may be classified into a first defect list (hereinafter referred to as PDL) and a second defect list (hereinafter referred to as SDL) according to the size of the management area.

PDL refers to a list of addresses of defective areas detected by a verification operation performed during a disc manufacturing process or an initialization process. In this PDL, the smallest defective recording unit, i.e., the start address of a defective sector, is recorded. Accordingly, the disk driver reads the PDL in the initial write operation and records the information by linearly shifting the defective sector in a skipped form. In this case, the sector following the defective sector has a jumped value while the physical address has a sequential value with respect to the sector before the defective sector. Also, in the reproducing operation, the PDL is read so that the information of the defective sector is not reproduced.

SDL means a list of addresses of defective areas and addresses of spare areas detected by a verification operation performed for rewriting on a disc. This SDL is to manage defective areas in units of ECC blocks to prevent the information recorded in units of blocks, for example, Error Checking and Correction (ECC) blocks. The address of the defective ECC block (hereinafter referred to as a defective block) and the replacement ECC block (hereinafter referred to as a replacement block) included in the replacement area provided for replacing the defective area are constituted. In other words, in the SDL, a start address of a replacement block to be used in place of the defective block together with the start address of the defective block including at least one defective sector is recorded by the user. The ECC block is usually composed of 16 sectors. Accordingly, the disc driver reads the SDL during writing and writes data to the replacement block corresponding to the defective block. Also, at the time of reproduction, the disc driver reproduces data in the same manner as described above using SDL.

Such a PDL and an SDL are usually provided in a lead-in area arranged in the innermost part of the disc and a lead-out area arranged in the outermost part of the disc. DMA). This defect management area usually has a size of 2 ECC blocks.

On the other hand, as the recordable optical disc medium has become larger, the DVD-RAM having a capacity of 2.6 gigabytes (GByte) has recently emerged, followed by a DVD-RAM having a capacity of 4.7 gigabytes (GByte). As such, when the capacity of the disk increases, it is natural that the defect area also increases. Accordingly, in order to effectively manage the increased defect area, it is desirable to increase the size of the defect management area and the replacement area.

However, for compatibility of the disk driver, the data area of the disk is recommended in a specific address, for example, in the case of DVD-RAM, starting from 31000h. In other words, the size of the lead-in area of the disk is limited regardless of the capacity of the disk for driver compatibility. Accordingly, the defect management area is also limited, so that the defective area of the increased disk cannot be managed effectively. In this case, a fatal problem of inferior reliability of the disk occurs. Therefore, there is a demand for a method that can effectively manage the defect areas that are increased to the size of the limited defect management area.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an optical disc having a defect management area capable of effectively managing defect areas detected in a large capacity optical disc.

1 is a diagram showing a recording unit of SDL in a general DVD-RAM.

2 is a diagram showing a recording unit of SDL in a DVD-RAM according to the present invention;

In order to achieve the above object, an optical disc according to the present invention includes information on a defect block consisting of the number of the Nth zone and the position number of the defective block in the Nth zone, and the zone of which the replacement block corresponding to the defective block is included. And a defect management area in which a defect area list including information of a replacement block consisting of the number and the position number of the replacement block in the zone is recorded.

Other objects and advantages of the present invention in addition to the above object will become apparent from the description of the preferred embodiment of the present invention with reference to the accompanying drawings.

Prior to the description of the embodiments of the present invention, the background to which the technical spirit of the present invention is derived will be described.

As described above, the PDL and the SDL are recorded separately in the defect management area DMA of the optical disc. Here, the PDL is generated during the initialization of the disk and is mostly recorded by the producer, while the SDL is recorded while the user uses the disk. In other words, if a bad sector occurs while using the disk, the user must process the defective area with SDL managed by ECC block units in order to protect the previously recorded data. For this reason, SDL occupies most of the area in the defect management area. In addition, the portion where the recording amount increases in the defect management area while using the disc is the SDL for the increased defect block and the replacement block. Accordingly, the technical idea of the present invention is to reduce the size of the recording unit of the SDL as a way to increase the capacity of the limited defect management area.

On the other hand, the optical disc usually includes a reserved area as large as the size of the defect management area adjacent to the defect management area. It is also conceivable to use a surplus area to increase the size of the defect management area, but it is preferable to leave this surplus area as an optical disc with a capacity of 10 GByte or more in the future.

As described above, the technical idea of reducing the recording unit of the SDL can be achieved by reducing the size of the address indicating the position of the defective block and the address indicating the position of the replacement block.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to FIGS. 1 and 2.

Referring to Fig. 1, a recording unit of SDL for a 2.6-Gbyte DVD-RAM, which has recently been proposed, is shown. The SDL of this DVD-RAM is allocated 8 bytes, i.e., 64 bits, for one defective block. Of these 64 bits, 24 bits are allocated to addresses related to defective blocks and replacement blocks. In detail, 24 bits are allocated to the first sector address of the defective block and the lowest 24 bits are allocated to the address of the first sector of the replacement block. The most significant bit of the 64 bits is allocated to a status flag (FRM) indicating whether or not there is a replacement block, and the surplus bits are located between the status flag (FRM) and the address of the defective block and between the defect block address and the replacement block address. Assigned to (RSV).

Referring to FIG. 2, a recording unit of an SDL for a DVD-RAM according to an embodiment of the present invention is shown. In the recording unit of the SDL shown in FIG. 2, the defective block and the replacement block are indicated by the zone number and the position number of the defective block and the replacement block in the zone, respectively.

In general, a DVD-RAM is preformatted in a zoned constant linear velocity (CLV) manner to record a larger amount of information. This zone CAV method divides an optical disc into at least two or more zones including a predetermined number of tracks, and preformats the number of sectors per track according to the position of each zone. Thus, tracks in the same zone have the same number of sectors but smaller or more sectors than tracks in other zones. In the case of the zone CLV DVD-RAM, each ECC block may be indicated by the number of the corresponding zone and the position number of the ECC block in the zone. Accordingly, the defective block and the replacement block in the recording unit of the SDL may also be indicated by the number of the corresponding zone and the position number of the defective block or the replacement block in the zone. In this case, the recording unit of the SDL is reduced from the existing 8 bytes to the size of 5 bytes.

In detail, a DVD-RAM having a capacity of 4.7 gigabytes (GByte) is divided into 35 zones, and thus, 6 bits are allocated to the number of zones containing defective blocks or replacement blocks. The position number of the defective block in the zone indicates how many times the defective block is located in the zone. In the case of DVD-RAM having a capacity of 4.7 gigabytes (GByte), the maximum data block in each zone is shown. The number is 5774 (Zone 34), 13 bits is enough, but it is allocated in 2 bytes. In addition, the position number of the replacement block in the zone indicates how many times the block to be replaced is also located in the zone. In the case of a DVD-RAM having a capacity of 4.7 gigabytes (GByte), The number of spare blocks is 177 (34 zones), and 8 bits are sufficient. In addition, as shown in FIG. 1, the most significant bit is allocated to a status flag (FRM) indicating whether a replacement block exists, and the status flag (FRM) is redundant between the defect block position and the defect block position and the replacement block position. Allocates to bits RSV. As a result, the recording unit of the SDL is 5 bytes.

Accordingly, the number of defect blocks recordable in the SDL according to the SDL recording unit shown in FIG. 1 is 4093 (that is, (16 * 2018) / 8-3 = 4093), while the SDL recording unit shown in FIG. As a result, the number of recordable defect blocks in the SDL is 6055 (that is, (16 * 2018) / 5-3 = 6550), which is about 60% higher than before.

In addition, when the number of replacement sectors becomes much larger in the future, it is possible to allocate 2 bytes as a position of a block to replace in the corresponding zone. In this case, the number of recordable defect blocks in the SDL is 5458 (that is, (16 * 2018) / 6-3 = 5458), which has an effect of increasing about 33%.

As described above, according to the optical disk according to the present invention, by reducing the size of the recording unit of the SDL recorded in the defect management area, more defect blocks can be managed by the defect management area of a limited size. Accordingly, it is possible to effectively manage the defective area of the large capacity optical disc, thereby improving the reliability of the optical disc.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

Claims (2)

In an optical disk composed of at least two zones, Information of a defective block comprising a number of an Nth zone and a position number of a defective block in the Nth zone, And a defect management area in which a defect area list including information of a replacement block including a number of a zone including a replacement block corresponding to the defect block and a position number of a replacement block in the zone is recorded. Optical disc. The method of claim 1, The defect area list includes A status flag indicating whether the replacement block exists; And redundant bits arranged adjacent to the defective block information and the replacement block information.