Method for registering, in a defect map, addresses of...

Details Method for registering, in a defect map, addresses of... Method for registering, in a defect map, addresses of...

2000-06-20

2003-11-25

Beausoliel, Robert (Department: 2184)

Error detection/correction and fault detection/recovery

Data processing system error or fault handling

Reliability and availability

C714S006130, C369S053150, C369S053170

Reexamination Certificate

active

06654904

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to a defect register method for registering each address of defective sectors arising in a data recording medium, such as a disk recording medium, in a defect map, a recording medium in which the defect map is registered and which is computer-readable, and a disk apparatus that refers to the defect map where addresses of defective sectors in the disk recording medium are registered and accesses the disk recording medium.
2. Description of the Related Art
Each surface of a disk (disk recording medium) in a disk apparatus is divided into a plurality of tracks, and each track is divided into a plurality of sectors. The disk apparatus refers to a defect map where addresses of defective sectors are registered, accesses a non-defective sector with a read/write head that is provided for every disk surface, and writes data in the sector or reads data from the sector. The defect map is classified into a primary defect map (PDM) and reassign defect map (RDM).
Each sector in the disk apparatus has an absolute block address (ABA). In addition, each head and disk surface has a head identification number HED, each track on a disk surface has a cylinder identification number CYL, and each sector in a track has a sector identification number SEC. The disk apparatus identifies a track by the HED and CYL.
When formatting a disk, the disk apparatus inspects all sectors, generates a PDM where positional information of defective sectors (initial defective sectors) is registered, and records this PDM in a map recording medium (a system reserve region that is part of the disk, a nonvolatile semiconductor memory apparatus, or the like). A logical block address (LBA) is assigned to a normal sector that is not registered in the PDM. The positional information registered in the PDM is an ABA or false logical block address (F.LBA) of an initial defective sector. The F.LBA is an LBA that would be assigned if the defective sector were normal.
In addition, if a defective sector (a subsequent defective sector) arises after the completion of formatting, the disk apparatus performs alternative processing of this subsequent defective sector. Furthermore, the disk apparatus registers an LBA of the subsequent defective sector and an LBA of an alternative sector in the RDM, and records this RDM in the map recording medium.
FIG. 12
is an example of initial defective sectors in a track that is part of a disk. In
FIG. 12
, “x” shows an initial defective sector. In addition, let a track having a cylinder identification number CYL and a head identification number HED be T(CYL, HED). T(
1
,
0
) means a track of CYL=1 and HED=0. In addition, ABA are assigned in the order of tracks T(
0
,
0
), T(
1
,
0
), T(
2
,
0
), . . . Furthermore, each sector length (the number of sectors) T.LE of tracks T(
0
,
0
), T(
1
,
0
), T(
2
,
0
) is 10. Moreover,
FIG. 12
is just a schematic drawing, and the T.LE described above is, for example, 200 to 400 in an actual disk apparatus.
FIGS. 13A
to
13
C are explanatory diagrams of the structure of PDM generated for the initial defective sectors, shown in
FIG. 12
, in a conventional disk apparatus.
FIG. 13A
shows the PDM where an absolute block address of each initial defective sector (D.ABA) is individually registered.
Nevertheless, since the memory capacity of an entire disk apparatus sharply increases recently, a total number of defective sectors also increases with relation to that. Therefore, a data amount of the PDM in
FIG. 13A
where each defective sector is individually registered becomes huge. In a current disk recording medium having high recording density, such a probability that defective sectors are continuous is high, and hence a PDM where each series of defective sectors with continuous ABA is registered in a batch by registering a position and sector length (the number of sectors) of the series of defective sectors is devised as shown in
FIGS. 13B and 13C
.
FIG. 13B
shows a PDM where a series of defective sectors consisting of defective sectors with continuous ABA is registered in a batch by registering a first absolute block address of the series of defective sectors (D.ABA.ST), and defective sector length of the series of defective sectors (D.LE). In addition,
FIG. 13C
shows a PDM where a series of defective sectors consisting of defective sectors with continuous ABA is registered in a batch by registering a false logical block address of the series of defective sectors (F.LBA), and defective sector length of the series of defective sectors (D.LE) In
FIGS. 13B and 13C
, two defective sectors, which have continuous ABA and have register numbers X of 0 and 1, shown in
FIG. 13A
, respectively, are registered in a batch at the register number Y=0. Furthermore, four defective sectors, which have continuous ABA and have register numbers X of 2 to 5, shown in
FIG. 13A
, respectively, are registered in a batch at the register number Y=1.
Furthermore, a data amount of the PDM is reduced by dividing the D.ABA.ST or F.LBA into upper bits and lower bits, registering the upper bits in a virtual track table (VTT), and registering the lower bits and D.LE described above in a virtual sector table (VST).
The disk apparatus obtains a track (CYL and HED where the LBA described above exists), where an LBA that the disk apparatus is requested by a host system to access exists, with referring to the PDM. Next, the disk apparatus generates an ID table (a table for associating a SEC of each sector and the LBA assigned) of this track with referring to the PDM. Then, by referring to this ID table, the disk apparatus accesses the sector having the LBA requested. In addition, if the alternative processing was performed to the LBA requested, the disk apparatus accesses its alternative sector with referring to the RDM.
The processing to assign an LBA is just the processing of generating an ID table with referring to a PDM. It is conceivable that after generating the PDM, the disk apparatus generates the ID table of all the tracks and records this ID table of all the tracks in a system reserve region and the like. Nevertheless, since a data amount of the ID table of all the tracks is huge, it is not desirable to record the ID table of all the tracks in a system reserve region and the like. For this reason, the disk apparatus generates an ID table of a track, being accessed, on each occasion. If the contents of the PDM are the same, an ID table having the same contents is generated for every access.
Nevertheless, in the conventional PDM where the initial defective sectors with continuous ABA are registered in a batch, there is such a possibility that a normal sector that is not registered in a PDM is erroneously made to be defective when an LBA is assigned by generating an ID table of a track. Therefore, in order to avoid such a case, it becomes necessary to impose a burden on another mechanism such as modification of a disk controller (hardware comprising a logic circuit and a counter circuit), or defect correction by a micro processing unit (MPU). Thus, even if a data amount of the PDM can be reduced, it is obliged to modify another mechanism for the sake of that, and complicated processing is required.
FIGS. 14A
to
14
C are explanatory diagrams of track ID tables generated for initial defective sectors, shown in
FIG. 12
, in a conventional disk apparatus.
FIG. 14A
shows an ID table of the track T(
0
,
0
),
FIG. 14B
shows an ID table of the track T(
1
,
0
), and
FIG. 4C
shows an ID table of the track T(
2
,
0
). In addition, “x” represents a SEC to which an LBA is not assigned.
If a series of initial defective sectors passing over tracks is registered in a batch in a PDM, it arises that an LBA is not assigned to each of sectors in spite of the sectors being not registered in the PDM. For example, if a series of initial defective sectors passing over tracks such as the initial defective sectors having ABA=8, . . . , 11 in
FIG. 12
is registered in a batch at the

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