Dynamic information storage or retrieval – Control of storage or retrieval operation by a control...
Reexamination Certificate
1998-12-24
2001-10-09
Psitos, Aristotelis M. (Department: 2651)
Dynamic information storage or retrieval
Control of storage or retrieval operation by a control...
C369S053370, C369S275300, C369S053110, C369S047160
Reexamination Certificate
active
06301208
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a data readable an d writable optical disk and an optical disk apparatus for driving it.
In a rewritable optical disk capable of repeatedly writing data in arbitrary positions on the disk and reading out data from arbitrary positions on the disk, data is generally written in units of one sector. In each sector, sector address data and error correction coded data are written.
To the contrary, in a recently standardized large-capacity rewritable optical disk 120 mm in diameter called a DVD-RAM, data can be written in units of not one sector but one error correction block (ECC block) obtained by error correction coding of a plurality of sectors in order to improve the data error correction ability. Similarly, in a DVD-ROM as a read-only optical disk, data is written in units of one error correction block formed from 16 sectors each including 2,048-byte data. In the DVD-ROM, both an error correction block and sector address information undergo error correction coding similar to data, thereby attaining a structure virtually free from any error.
In the DVD-RAM, address information in unit of one sector are written as emboss pits in the disk in advance. In writing data, a plurality of sectors (16 sectors) constitute one error correction block. Thus, address information can always be obtained in units of one sector. Even when, for example, the optical head erroneously moves to an adjacent track during writing, the write error can be limited to one sector, and the seek time can be shortened. Further, since a periodic signal corresponding to the sector period can always be obtained from the address information of a sector during a write/read, the spindle motor for rotating the optical disk can be controlled in accordance with this periodic signal.
In a method of writing address information in units of one sector, like a conventional DVD-RAM, each sector must have many areas other than the area for writing data, such as a buffer area for coping with a change in actual sector length on the disk caused by variations in rotation speed or decentering of the disk during writing/reading out data, and a buffer area for co ping with random shifts of write-in positions and deterioration of start and end positions in the phase change recording scheme, in addition to the address information area (header field). This decreases the format efficiency. To ensure a sufficient write-in capacity, the write-in density must be increased. If the write-in density is not changed, the write-in density decreases.
As a method of writing data in an optical disk without forming address information in units of one sector, a groove in the optical disk is wobbled to write address information as an FM signal, and data is written in units of one error correction block on the basis of the address information. This is employed in a CD-R, CD-RW, and the like. In this case, the address of an error correction block is determined only after data is written, so data is generally difficult to efficiently write in an arbitrary position.
The address information of an error correction block and the address information of a sector cannot be extracted unless error correction coded data is decoded. If an address error occurs during a write, the error cannot be corrected, and data may be written in an erroneous address. Furthermore, the error correction must be executed for the address information even if the seek operation is performed for another track. As a result, the time required for seeking a target address becomes long, so that the wait time in data reading and writing becomes long. In addition, address information written as a groove wobble may deteriorate during a several number of writes.
In an area where data is written, a periodic signal corresponding to the sector period necessary to control the spindle motor can be obtained from the optical disk. However, in an area where no data is written, no periodic signal can be obtained. Finalization for writing a dummy signal for generating a periodic signal must be performed for a plurality of tracks after data is written, which prolongs the write-in time.
As described above, of conventional rewritable optical disks, an optical disk for writing address information in units of one sector as pre-pits requires, for each sector, buffer areas for coping with a change in actual sector length resulting from variations in rotation speed or decentering of the disk and coping with random shifts of write-in positions and deterioration of start and end positions in the phase change recording scheme. This increases the number of areas other than the area for writing data and decreases the format efficiency.
In an optical disk in which a groove is wobbled to write address information and data is written in units of one error correction block, data is difficult to efficiently write in an arbitrary position. Address information in units of one sector cannot be obtained unless error correction coded data is decoded. Moreover, finalization for generating a periodic signal for controlling the spindle motor must be performed to extend the write-in time.
BRIEF SUMMARY OF THE INVENTION
It is an object of the present invention to provide a rewritable optical disk capable of increasing the format efficiency, efficiently writing data in an arbitrary position, and obtaining address information in units of one sector without decoding error correction coded data, and an optical disk apparatus for driving the optical disk.
It is another object of the present invention to provide an optical disk and optical disk apparatus capable of controlling rotation using a signal obtained from the optical disk without any extra process of finalization.
According to the present invention, there is provided An optical disk used for writing and reading data in units of an error correction block containing a plurality of sectors by means of a light beam comprising land and groove tracks arranged adjacent to one another, and a plurality of recognition marks formed on a boundary between the land and the groove tracks to recognize a position of the error correction blocks.
According to the present invention, there is provided an optical disk apparatus comprising an optical head facing an optical disk for writing and reading data therein and therefrom, the optical disk having land and groove tracks arranged adjacent to one another and a plurality of recognition marks formed on a boundary between the land and the groove tracks and used for recognizing respective positions of the error correction blocks, and the optical head detecting the recognition marks to output a detection signal, a signal generator which generates a recognition signal corresponding to the recognition marks on the basis of the detection signal from the optical head, a driver which drives the optical head in accordance with the recognition signal and write information in a writing mode to write data in the error correction blocks corresponding to the detected recognition marks, and a signal processor which processes data read out from the optical disk by the optical head to output a reproduced signal.
In this way, recognition information of the error correction block is written as emboss pits in the optical disk. Data of each sector of the error correction block and address information of the sector are written on the basis of this recognition information. This allows to form, in units of one error correction block, buffer areas for coping with a change in actual sector length on the disk arising from variations in rotation speed or decentering of the disk during writing/reading out data and coping with random shifts of write-in positions and deterioration of start and end positions in the phase change recording scheme. Compared to a conventional optical disk in which address information in units of one sector is written as emboss pits, the buffer area can be greatly decreased to widen the area for writing data, resulting in a high format efficiency.
Since the positions of error correction blocks o
Kobori Hiromichi
Sugaya Toshihiro
Watabe Kazuo
Kabushiki Kaisha Toshiba
Pillsbury & Winthrop LLP
Psitos Aristotelis M.
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