Dynamic information storage or retrieval – Information location or remote operator actuated control – Selective addressing of storage medium
Reexamination Certificate
2001-10-12
2004-02-03
Neyzari, Ali (Department: 2655)
Dynamic information storage or retrieval
Information location or remote operator actuated control
Selective addressing of storage medium
C369S047100, C369S053410
Reexamination Certificate
active
06687198
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to access of information stored on an information storage medium such as a DVD (Digital Versatile Disc) or the like, and more particularly to access of control information such as synchronous signals, address information or the like.
2. Description of Related Art
Among bulk information storage media typified by DVD, on a DVD-R (DVD-Recordable) into which information can be written or a DVD-RW (DVD-ReWritable) in which information is rewritable, information is stored using groove tracks as information storage tracks. The groove track is interposed between land tracks, which are guide tracks for guiding a light source such as a laser beam or the like. When viewed from the light source, the groove tracks and the land tracks form convex portions and concave portions respectively. That is, the convex-concave tracks are formed along the circumference of an optical disk.
Furthermore, information on the attribute of stored information and information for attaining synchronization of data frames as a unit of stored information are stored as control information. This information is arranged on the land tracks which are not designed to store information, and is referred to as Land Pre Pit (hereinafter described as LPP) information.
In information storage media such as DVD-R, DVD-RW or the like, an information group of two kilo-bytes is configured as one data sector, and LPP information has a bit configuration with 13 bits as a unit for each data sector.
FIG. 15
shows a bit configuration per data sector of LPP information. This is a configuration where a synchronous mark LSY is stored as the first bit of LPP information, where address bits indicating addresses among data sectors (hereinafter referred to as relative addresses) (Relative Addresses 3 to 0) are stored as the second to fifth bits of LPP information, and where data bits (Data 7 to 0) are stored as the sixth to thirteenth bits of LPP information. A one-bit-width synchronous mark LSY arranged at the head of a sector differs depending on differences among later-described 26 data frames (see
FIG. 17
) into which one data sector is divided. To be more specific, the data frames are numbered from 0. The data frames of even numbers are classified into an Even region, whereas the data frames of odd numbers are classified into an Odd region. In this instance, a synchronous mark LSY of “111” channel bits is set in the case of arrangement in a frame in the Even region, and a synchronous mark LSY of “110” channel bits is set in the case of arrangement in a frame in the Odd region. The synchronous mark LSY attains synchronization among sectors and determines whether a certain one of the frames belongs to the Even region or to the Odd region. Data are stored in all of the following 12 bits as “0” or “1”. On the medium, while bits “0” are denoted by “100” channel bits, bits “1” are denoted by “101” channel bits. The relative addresses of four bits, i.e. the second to fifth bits in the former half define the sequence of the sectors. Namely, as shown in
FIG. 16
, one data block is configured by taking together first to sixteenth sectors that have been identified continuously according to an ascending sequence as the addresses “0000” to “1111”. Parity and block addresses for error correction codes (ECC) are allocated to the other eight data bits, i.e. the sixth to thirteenth bits. One data block is divided into some sectors, and errors are detected and corrected as to data bit strings detected from a predetermined number of the sectors. As for bit strings of LPP information detected on the basis of a synchronous mark LSY, if consecutiveness of the relative addresses of four bits among the data sectors is confirmed and if it can be confirmed that the data bit strings are read out correctly owing to detection and correction of errors of the data bit strings in the predetermined number of sectors, it is concluded that access to LPP information has been made accurately. Thus, the readout state is locked.
FIG. 17
shows a track format of one data sector. As described above, one sector is divided into 26 data frames, which are numbered from 0. The frames of even numbers are classified into the Even region, whereas the frames of odd numbers are classified into the Odd region. Basically, LPP information is arranged bit by bit in the frames in the Even region. That is to say, a synchronous mark LSY is arranged in the zeroth frame, address bits are arranged in the second, fourth, sixth and eighth frames, and data bits are arranged in the tenth, twelfth, fourteenth, sixteenth, eighteenth, twentieth, twenty-second and twenty-fourth frames. On the other hand, the Odd region is secured as a spare data frame region. That is to say, the first frame is secured as a spare region for the synchronous mark LSY in the zeroth frame, the third, fifth, seventh and ninth frames are secured as spare regions for the address bits in the second, fourth, sixth and eighth frames respectively, and the eleventh, thirteenth, fifteenth, seventeenth, nineteenth, twenty-first, twenty-third and twenty-fifth frames are secured as spare regions for the data bits in the tenth, twelfth, fourteenth, sixteenth, eighteenth, twentieth, twenty-second and twenty-fourth frames respectively.
FIG. 18
shows a case where LPP information of the above track format is arranged on an information storage medium such as an optical disk or the like. LPP information is arranged on land tracks coincident with frame head positions of groove tracks on which information is stored. By irradiating the groove tracks formed along the circumference of the medium with light such as laser beams emitted from a light source, the information stored on the groove tracks is read out. At this moment, the spot radius of the light source is set greater than the width of the groove tracks so that some of the land tracks are also irradiated. Due to this configuration, the LPP information arranged on the land tracks is read out. LPP information is basically attached to each one of the data frames in the Even region and thus is arranged repeatedly at a pitch corresponding to two of the data frames on the disk. This arrangement is continuously repeated toward the center of the disk. Therefore, there is a fear that pieces of LPP information on two of the adjacent land tracks between which a corresponding one of the groove tracks is interposed may adjoin each other while overlapping with each other in a scanning direction of the light source. This hampers accurate read-out of LPP information. Thus, in general, in the case where pieces of LPP information overlap with each other, one of them is transferred to the Odd region, i.e. to an adjacent data frame. In this case, if the number of the data frame in the Odd region to which that piece of LPP information has been transferred is set as a number which is greater by one than the number of the data frame in the Even region to which that piece of information belongs intrinsically so that the Odd region is configured as a spare region for the Even region, those pieces of information can be prevented from overlapping with each other on the disk.
FIG. 19
shows an LPP access portion
1000
of the related art. Three-channel-bit LPP information read out by a light source is inputted to a three-channel-bit shift register
101
. An LPP pattern comparing portion
102
subjects the LPP information inputted from the shift register
101
to comparison and finds out whether the LPP information coincides with “111” channel bits as a synchronous mark in the Even region, “110” channel bits as a synchronous mark in the Odd region, “100” channel bits indicating a data bit “0”, or “101” channel bits indicating “1”. If the LPP information coincides with a synchronous mark LSY, the LPP pattern comparing portion
102
outputs the synchronous mark LSY to a synchronous mark detecting portion
103
. If the LPP information coincides with data bits, the LPP pattern comparing portion
102
outputs a data bit signal La/Ld indicating
Arent Fox Kintner & Plotkin & Kahn, PLLC
Neyzari Ali
LandOfFree
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