Error detection/correction and fault detection/recovery – Data processing system error or fault handling – Reliability and availability
Reexamination Certificate
1998-12-23
2002-05-07
Lee, Thomas (Department: 2182)
Error detection/correction and fault detection/recovery
Data processing system error or fault handling
Reliability and availability
C714S006130, C714S005110, C714S048000
Reexamination Certificate
active
06385736
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates in general to a rewritable optical recording medium system, and more particularly to a method and apparatus for managing defect areas of an optical recording medium.
2. Description of the Prior Art
Optical recording media are generally classified into three types, or a read only, ROM type, a once writable, WORM type and a repeatedly writable, rewritable type according to the possibility of repetitive writing.
The repeatedly writable optical recording media may be, for example, a rewritable compact disc (CD-RW), a rewritable digital versatile disc (DVD-RAM or DVD-RW), etc.
In such a rewritable optical recording medium, however, because information write/read operations are repeatedly performed according to the availability of the optical recording medium, a mixing ratio of a mixture constituting an information recording layer in the optical recording medium becomes different from the initial value with the lapse of time. For this reason, the information recording layer loses its characteristics, resulting in an error being generated in the information write/read operations.
This phenomenon is called a deterioration, which is revealed as defect areas when formatting, write and read commands of the optical recording medium are performed.
The defect areas of the rewritable optical recording medium may be generated due to a scratch on its surface, a particle such as dust, an error in manufacturing process, etc., in addition to the above-mentioned deterioration.
In this connection, the defect areas of the rewritable optical recording medium must be managed to prevent data from being written/read thereon.
To this end, a conventional rewritable optical recording medium such as a rewritable optical disc comprises defect management areas (referred to hereinafter as DMAs) provided in lead-in and lead-out areas, as shown in FIG.
1
. Each DMA includes a primary defect list (referred to hereinafter as PDL) which is a primary defect data storage unit, and a secondary defect list (referred to hereinafter as SDL) which is a secondary defect data storage unit.
A data area is managed in the unit of zones. Each of the zones is composed of a user area, in which actual data is written, and a spare area to be used when the user area is subjected to a defect. As shown in
FIG. 2
, a guard area is assigned between the adjacent zones to make a distinction therebetween.
The PDL is generally adapted to store entries of defect sectors generated in a disc manufacturing process and entries of defect sectors detected in disc formatting, or initialization and re-initialization.
The SDL is listed in the unit of blocks. This SDL is adapted to store entries of defect areas generated after formatting or entries of defect areas incapable of being stored in the PDL during formatting. Each SDL entry is provided with an area for storing a sector number of a first sector in a block in which a defect sector is generated, and an area for storing a sector number of a first sector in a replacement block with which the defect sector block is to be replaced.
In such an optical disc, each sector has a logical sector number (referred to hereinafter as LSN) and a physical sector number (referred to hereinafter as PSN). The LSNs are presented to only the user areas in which actual data are written. The PSNs indicate physical positions on the disc assigned to all sectors in the disc manufacturing process, respectively.
Hence, if no defect is present in the data area, the LSNs will be assigned to only the user areas in which actual data are written, whereas the PSNs will be assigned to all areas, as shown in
FIG. 3
a.
On the other hand, in the case where defects are present in the data area, defect areas (i.e., defect sectors or defect blocks) in the data area must be replaced with normal areas. Generally, slipping replacement and linear replacement methods have been recommended by the optical recording medium standard group.
The slipping replacement method is applied to the case where a defect area is registered in the PDL. In this slipping replacement method, as shown in
FIG. 3
b
, if a defect sector listed in the PDL is present in the user area in which actual data is written, then it is jumped over and replaced with a normal sector subsequent thereto for the writing of data. In this case, a PSN is present in the defect sector listed in the PDL as it is, but no LSN is present in that defect sector because data is not written or read thereon. Instead, the same number of LSNs as that of defect sectors is assigned in the spare are. The spare area with the LSNs assigned become the user area by formatting.
The linear replacement method is applied to the case where a defect area is registered in the SDL. In this linear replacement method, as shown in
FIG. 3
c
, if a defect block listed in the SDL is present in the user area or the spare area, then it is replaced with a block-unit replacement area assigned in the spare area, for the writing of data. In this case, PSNs assigned respectively to sectors in the defect block are present as they are, but LSNs are moved together with data to the replacement block.
However, the above-mentioned slipping replacement and linear replacement methods require a method for searching the optical recording medium for defect sectors registered in the PDL and defect blocks registered in the SDL and a method and apparatus for efficiently managing the defect sectors and defect blocks.
SUMMARY OF THE INVENTION
Therefore, it is an object of the present invention to provide a method and apparatus for efficiently managing defect areas of an optical recording medium.
It is another object of the present invention to provide a method and apparatus for managing defect areas of an optical recording medium, in which a data write section and data read section search for and manage defect areas registered in a PDL and SDL.
It is a further object of the present invention to provide a method and apparatus for managing defect areas of an optical recording medium, in which a data write/read controller searches for and manages defect areas registered in a PDL and SDL.
It is yet another object of the present invention to provide a method and apparatus for managing defect areas of an optical recording medium, in which a PSN corresponding to an LSN sent from a host is accurately searched for, using a table.
In accordance with one aspect of the present invention, there is provided a method of managing defect areas of an optical recording medium, comprising the first step of reading a defect management area list and storing the read defect management area list; the second step of comparing a physical sector number of a current position with the defect management area list stored at the first step; and the third step of writing or reading no data on a physical sector of the current position if it is determined at the second step that the physical sector number of the current position is the same as a physical sector number in the defect management area list stored at the first step.
Preferably, the comparison step includes the step of reading a physical sector number of a first defect area subsequent to a first sector to be written or read, from the defect management area list stored at the storage step, storing the read physical sector number and comparing the stored physical sector number with the physical sector number of the current position.
The comparison step includes the step of, if it is determined that the physical sector number of the current position is the same as the stored physical sector number, reading a physical sector number subsequent to the stored physical sector number, from the defect management area list stored at the storage step and updating the stored physical sector number to the read physical sector number.
The comparison step includes the step of, when the physical sector number of the defect area is stored, indicating that the defect area is that registered in a primary data list or a secondary data list.
Pre
Jeong Kyu Hwa
Kang Dong Chul
Lee Thomas
LG Electronics Inc.
Mai Rijue
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