Dynamic information storage or retrieval – Condition indicating – monitoring – or testing – Including radiation storage or retrieval
Reexamination Certificate
1998-11-13
2001-03-20
Hindi, Nabil (Department: 2651)
Dynamic information storage or retrieval
Condition indicating, monitoring, or testing
Including radiation storage or retrieval
Reexamination Certificate
active
06205099
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a recordable and reproducible disk having a sector structure and a disk recording and reproducing apparatus, and more specifically to a method for managing a defect of a disk susceptible to a scratch and an apparatus for recording information onto and reproducing information from the disk.
2. Description of the Related Art
A representative example of a disk having a sector structure includes an optical disk. In recent years, capacity of optical disks has been remarkably increased, and data has been recorded on an optical disk in high density. Therefore, it is important to ensure reliability when information is recorded onto an optical disk or when information is reproduced from an optical disk.
FIGS. 1A through 1C
show a general physical and logical structure of a disk medium
1
.
FIG. 1A
is a schematic diagram of the disk medium
1
. The disk medium
1
in a circular shape includes a plurality of concentrically formed tracks
2
. Each track
2
is divided into a plurality of sectors
3
in a radius direction. A leading edge of each sector
3
is provided with an absolute address called a physical sector address. Herein, the “leading edge” refers to an edge of each sector
3
in a rotation direction in which the disk medium
1
is rotated.
FIG. 1B
schematically shows a sector management method. Tracks are assigned numbers (0 to T). Sectors included in each track are assigned numbers (0 to S). Each sector can be accessed by specifying a track number and a sector number.
FIG. 1C
shows a structure of areas of the disk medium
1
(FIG.
1
A). The disk medium
1
(
FIG. 1A
) is composed of a disk information area
4
and a data recording area
5
. The disk information area
4
is positioned on an innermost side and on an outermost side of the disk medium
1
(FIG.
1
A). In the disk information area
4
, parameters and the like required for accessing a disk are stored. The data recording area
5
is positioned between the disk information areas
4
on an innermost side and on an outermost side. In the data recording area
5
, ordinary data such as video data and audio data is stored. For recording and reproducing data, a disk is initialized, and data is written onto the data recording area
5
.
In recording of information onto and reproduction of information from an optical disk, the procedure described below is used for ensuring reliability. More specifically, in the case where there is a sector on a disk in which information cannot be recorded or reproduced, the sector is registered as a defective sector, and the use of the defective sector is prohibited. The procedure will be described in accordance with International Standardization Organization ISO/IEC10090.
In the case where a defect is found in a sector during recording and reproduction of data, the sector is registered as a defective sector in a Primary Defect List (hereinafter, referred to as a “PDL”) and/or in a Secondary Defect List (hereinafter, referred to as an “SDL”). Herein, the “defect” refers to the case where there is a physical scratch in a sector in a track. A disk recording and reproducing apparatus does not use the defective sector registered in the PDL or the SDL in the subsequent recording and reproduction, thereby being capable of recording and reproducing data without accessing the defective sector. The PDL and the SDL are stored in the disk information area
4
in FIG.
1
C.
FIG. 10A
shows a structure of the PDL. The PDL is composed of a PDL identifier identifying the PDL, the number of entries showing the number of defective sectors registered in the PDL, and n entries (PDE
1
to PDEn) storing addresses of actual defective sectors.
FIG. 10B
shows a structure of the PDEn. The PDEn stores an address of a defective sector specified by a track number and a sector number. The PDE
1
to PDE(n−1) also have the same structure as that of the PDEn.
FIG. 11A
shows a structure of the SDL. In the same way as in the PDL, the SDL is composed of an SDL identifier identifying the SDL, the number of entries showing the number of defective sectors registered in the SDL, and m entries (SDE
1
to SDEm) storing addresses of actual defective sectors.
FIG. 11B
shows a structure of the SDEm. The SDEm stores a defective sector address and an alternative sector address thereof. The defective sector address and the alternative sector address are both specified by a track number and a sector number. The SDE
1
to SDE(m−1) also have the same structure as that of the SDEm. The difference between the PDL and the SDL is that the SDL has an alternative sector address.
Next, two algorithms for avoiding a defective sector, i.e., a Slipping Algorithm and a Linear Replacement Algorithm will be described.
FIG. 12
shows a defective sector and an alternative sector thereof to which the Slipping Algorithm is applied. The Slipping Algorithm is a defect handling algorithm conducted during disk inspection and formatting.
A user area and a spare area of a schematic area
1201
shown in
FIG. 12
are formed as part of the data recording area
5
(FIG.
1
C). The user area is provided for the purpose of actually storing data, and data is usually stored in this area. The spare area is provided for the purpose of handling a defective sector. More specifically, the spare area is provided considering that there may be a defective sector in the user area in which data cannot be stored due to a scratch or the like.
In order to access the user area, a disk is assigned a logical sector number (hereinafter, referred to as an “LSN”). A user or an external terminal controlling a disk recording and reproducing apparatus accesses a sector of a disk, using an LSN, and reads and writes data.
A logical area
1202
shown in
FIG. 12
shows results obtained by handling a defective sector by the Slipping Algorithm. It is assumed that a defective sector SD
1
having one sector of defect and a defective sector SD
2
having two sectors of defect are present in the user area. The defective sectors SD
1
and SD
2
are not assigned LSNs, and three sectors which cannot be used due to defects are reserved by using the spare area. As a result, the user area formally extends to the spare area as shown in
FIG. 12
, and an area with the same capacity as that which can be used without any defects is reserved.
Thus, in accordance with the Slipping Algorithm, the use of an address of a defective sector registered in the PDL can be avoided. Furthermore, by prescribing the spare area as an alternative area of a defective sector, a required recording area can be reserved.
FIG. 13
shows defective sectors and alternative sectors thereof to which the Linear Replacement Algorithm is applied. The Linear Replacement Algorithm is a defect handling algorithm generally conducted during recording and reproduction of data.
In
FIG. 13
, it is assumed that defective sectors LD
1
and LD
2
are present in the user area. Data of the defective sectors LD
1
and LD
2
is reserved in a selectively specified area of the spare area. According to the Linear Replacement Algorithm, LSNs (e.g., LSN
1
and LSN
3
) assigned to sectors before and after a defective sector refer to the sectors before and after the defective sector, and LSN
2
between LSN
1
and LSN
3
refers to an alternative sector in the spare area.
Thus, according to the Linear Replacement Algorithm, a defective sector is registered in the SDL, and an alternative sector is accessed in place of the defective sector; thus, the alternative sector is used as an alternative to the defective sector.
Hereinafter, a procedure of disk initialization will be described.
Initialization of a disk is performed at least once before data is written onto the disk. The procedure of initialization is as follows. First, specific test pattern data is written onto all the sectors, and the sectors of the disk are inspected based on whether or not the written data can be correctly read from all the sectors.
As described above, a defective sector from which da
Fukushima Yoshihisa
Ito Motoshi
Sasaki Shinji
Ueda Hiroshi
Hindi Nabil
Matsushita Electric - Industrial Co., Ltd.
Renner , Otto, Boisselle & Sklar, LLP
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