Dynamic information storage or retrieval – Information location or remote operator actuated control – Selective addressing of storage medium
Reexamination Certificate
2001-04-03
2003-03-04
Tran, Thang V. (Department: 2653)
Dynamic information storage or retrieval
Information location or remote operator actuated control
Selective addressing of storage medium
C369S030100
Reexamination Certificate
active
06529451
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an optical disk permitting reading and writing of data while being rotated at a constant angular velocity, and more particularly to an optical disk having a recording surface divided into a plurality of zones, with clocks of higher frequencies being used for the access to the more outward zones so that the recording linear density is substantially identical between the outer and inner zones.
The present invention also relates to an optical disk which contains different types of recording media for the respective zones, and in which the types of the respective zones can be altered during use of the disk.
The present invention also relates to an optical disk drive device used for writing in and reading from the above-mentioned optical disks.
Known optical disks of the type having a storage capacity of 1 GB on each surface have a format proposed in ECMA/TC31/92/36. According to this proposal, the recording surface of the optical disk is divided into a plurality of zones equally, i.e., such that the numbers of the physical tracks in the respective zones are substantially equal. The number of zones depends on the size of the sector. If each sector consists of 512 bytes, the number of the zones is 54. If each sector consists of 1024 bytes, the number of the zones is 30.
Each physical track has an integer number of sectors. The number of sectors in each track is constant throughout each zone. The number of sectors in each track is larger in more outward zones.
The optical disks that are available are either those of the R/W (read/write or rewritable) type which permit writing and rewriting as desired, and those of the WO (write-once) type which permit writing only once after fabrication, and those of O-ROM (embossed) type in which data is written at the time of fabrication, by embossing, and which do not permit writing after fabrication.
The number of sectors in each physical track differs from one zone to another, as described above. A complex algorithm is needed for indexing the physical location of the target sector when for instance the optical disk is used as a SCSI device, and is supplied with linear (consecutive-integer-numbered) logical addresses. Moreover, the data field in each sector in an innermost physical track of a certain zone and the header field in each sector in an outermost physical track of another zone next to and inside of the first-mentioned zone may be adjacent to each other, with the result that the crosstalk from the header field may degrade the quality of the data read from the data field. This is because the information in the header field is written in the form of pit (embossment) and has a greater degree of modulation, causing a greater crosstalk, while the information in the data field is magneto-optically written and has a smaller degree of modulation. In this connection, it is noted that within each zone, header fields in all the tracks are radially aligned and data fields in all the tracks are radially aligned, so that a header field and a data field will not be adjacent to each other.
It is also desired that recording areas of the R/W type, of the WO type and of the O-ROM type be co-existing in a single disk to expand the application of the disks. In the past, optical disks of the P-ROM type, in which the recording areas of the R/W type and the recording areas of the O-ROM type are coexisting, were available. But, no other combination of recording areas have been known.
SUMMARY OF THE INVENTION
An object of the invention is to provide an optical disk which enables quick indexing of the physical location of the target sector responsive to a given address.
Another object of the invention is to provide an optical disk permitting mixed presence of recording areas of different types.
A further object of the invention is to provide an optical disk drive device used for such optical disks.
According to a first aspect of the invention, there is provided an optical disk comprising a recording region, physical tracks in said recording region each corresponding to one revolution, said recording region being divided into a plurality of zones by one or more circular boundary lines centered on the center of the disk, each zone comprising a plurality of physical tracks adjacent to each other, wherein an integer number of sectors are provided in each physical track, the angular recording density is higher in the more outward zones such that the linear recording density is substantially constant throughout the recording region, and logical tracks are formed of a predetermined number of sectors, independent of the physical tracks.
With the above arrangement, each logical track is formed of sectors, independent of the physical tracks, and the number of the sectors in each logical track is constant throughout the recording region, regardless of the radial position of the sector within the recording region, so that the conversion between the logical track and sector addresses read from the disk, at the sectors being accessed by the read/write head, and the linear logical addresses (one-dimensional addresses, or addresses represented by consecutive integers) supplied from a host device is easy, and the grouping and defect management are easy.
The addresses written in headers of the sectors in the logical track in which data are actually recorded, including substitute sectors used in place of defect sectors, are preferably consecutive to further facilitate the conversion between the logical track and sector addresses read from the disk and the linear logical addresses supplied from the host device.
The difference obtained by subtracting the number of the logical tracks corresponding to each zone from the number of the logical tracks corresponding to another zone adjacent to and radially outside of said each zone is preferably constant.
With this arrangement, the address management of the disk is facilitated, and the number of the logical tracks in the zone in question can be determined through simple calculation on integers, without referring to a table for address conversion, and the determination of the target sector during seek operation can be made with ease.
The number of the physical tracks of zones adjacent to each other are preferably made equal by providing sectors in which data is not recorded.
With this arrangement, the calculation for determining the number of tracks to be traversed for accessing the target track is easy, and the management of the physical location is easy.
Addresses of the sectors in the tracks in which data is not recorded may be assigned independently of the addresses of the sectors in the tracks in which data is recorded. Similarly, addresses of the sectors in the test track in each zone are assigned independently of the addresses of the sectors in the tracks in which data is recorded. With this arrangement, management of the tracks in which data is not recorded and the test tracks is facilitated. The logical track and sector addresses are of consecutive values, so that the address management of the recorded data is facilitated. Access management of the test tracks is also facilitated.
The difference obtained by subtracting the number of sectors in each zone in which data is not recorded from the number of sectors in another zone adjacent to and outside of said each zone and in which data is not recorded is preferably constant.
With this arrangement, the number of the sectors in each zone in which data is not recorded can be determined through simple calculation on integers, without referring to a table, and the address management of the disk is easy.
Data may not be recorded in the outermost and innermost physical tracks in each zone. This arrangement avoids crosstalk at the boundary between zones. That is, the header fields are not necessarily aligned radially between different zones, and the header fields and the data fields of tracks adjacent to each other. However, by the above arrangement in which the outermost and innermost physical tracks are not used for recording data
Furukawa Teruo
Kondo Jun-ichi
Nakane Kazuhiko
Ohata Hiroyuki
Ototake Masafumi
Birch & Stewart Kolasch & Birch, LLP
Tran Thang V.
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