Dynamic information storage or retrieval – Binary pulse train information signal – Format arrangement processing for auxiliary information
Reexamination Certificate
2001-02-16
2004-08-31
Tran, Thang V. (Department: 2653)
Dynamic information storage or retrieval
Binary pulse train information signal
Format arrangement processing for auxiliary information
C369S124080, C369S053200
Reexamination Certificate
active
06785213
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to disk drive apparatuses for recording and reproducing (reading) data into and from disks for which data is rewritable, such as compact discs rewritable (CD-RWs), and to disk formatting methods.
2. Description of the Related Art
Recording media for storing a large amount of data are usually formatted logically in units of addresses. Disk-shaped recording media and tape-shaped recording media used for computers, for example, usually have numbered sectors divided into several areas and numbered tracks.
These recording media usually have overhead information including additional error-detecting and error-correcting bits, synchronization patterns formed of bits used for synchronizing clocks before reading or writing, and an unused space for adapting to differing speeds among drives. The overhead information (including sector address numbers, synchronization patterns, and a gap of the unused space) is separately written in a process called formatting.
CD-type disks, generally called compact disks, have a single helical data track starting from the center (inner periphery) of the disk and ending at an end (outer periphery) of the disk. Recordable disks and rewritable disks, such as compact discs recordable (CD-Rs) and CD-RWs, have a helical data track formed of a physical groove. In contrast, reproduction-only (read-only) disks, such as compact discs digital audio (CD-DAs) and compact discs read-only memory (CD-ROMs), have no physical groove serving as a data track.
In a CD-type signal format, bytes of data are arranged in units of frames, frames of data are arranged in units of sectors, and sectors serve as the minimum addressable units.
One frame has 2,352 bytes of data. Frame addresses are indicated by a time and a frame offset. More specifically, frame addresses are expressed by {M, S, F}, where M indicates the minutes, S indicates the seconds, and F indicates the frame offset within one second. One second includes 75 frames.
These frame addresses (MSF addresses) may be absolute (measured from the beginning of the physical data track) or may be relative (measured from the beginning of the current logical data track).
Frames of data may be arranged in units of packets. One packet has one link frame, four run-in frames, an actual data frame, and two run-out frames.
CD-Rs have variable-length packets. CD-RWs have fixed-length packets in which a total of 39 frames (32 actual data frames and seven overhead frames) are included per packet in the current formatting standard.
In the format for CD-DAs and CD-ROMs, a so-called lead-in area disposed near the beginning of the physical data track and the following program area are required. The program area is formatted in units of logical data tracks. In the format of CD-DAs and CD-ROMs, a so-called lead-out area disposed at the end of the last logical data track is also required.
Reproducing (reading) apparatuses for CD-DAs and CD-ROMs can search for a particular logical-data-track number. For this search, the lead-in area includes TOC information (table-of-contents information) and the TOC information includes absolute MSF address information for logical data tracks. The lead-in area also includes a pointer pointing to the lead-out area.
In many drive apparatuses, since servo calibration cannot be achieved in the radial direction, data cannot be read from disks unless both the lead-in area and the lead-out area exist.
As described above, CD-Rs and CD-RWs have a physical groove in which data is recorded, but reproduction-only (read-only) disks (CD-DAs and CD-ROMs) have no physical groove. In the reproduction-only (read-only) disks, a helical path formed of data pits and lands serves as a track which can be optically detected.
In many reproduction (reading) apparatuses, the number of times a pickup crosses the track formed of a pit string on the disk or the number of times the pickup crosses the groove is counted during movement in the radial direction.
Drive apparatuses for CD-Rs and CD-RWs have a groove detecting function, but drive apparatuses (reproduction-only (read-only) apparatuses) for CD-DAs and CD-ROMs may have no groove detecting function.
In some drive apparatuses, movement in the radial direction, which crosses a helical physical data track, may form an open loop, in which the number of times the physical data track is crossed is not increased.
Drive apparatuses which achieve an open-loop movement in the radial direction usually perform servo calibration in the radial direction by moving the pickup from the lead-in area to the lead-out area. Therefore, some drive apparatuses need to format all frames disposed between the lead-in area and the lead-out area.
After the format for CD-DAs and CD-ROMs had been developed, recordable (write-once) disks (CD-Rs) were introduced. CD-R recording has a very important feature of partially recording data into a disk and adding new data later. Since the original lead-in area cannot be changed in write-once disks when new data is added, this single lead-in area is insufficient. Therefore, a “session” technique was introduced, and the physical data track is formatted to have a plurality of sessions. In this case, each session has one lead-in area and one lead-out area. Up to 99 logical data tracks can be formed over all sessions. Each lead-in area except that for the last session includes a pointer pointing to the frame address of the next (possible) session.
The format for CD-ROMs and other formats can currently have a multi-session function for formatting the physical data track to have a plurality of sessions.
After that, rewritable (erasable) disks (CD-RWs) were developed. Like magnetic disks and tape, CD-RWs need generalized random-access recording. It is also necessary to maintain lower compatibility with single-session disks (such as CD-DAs) and multi-session disks. For tape and magnetic disks, special-format magnetic heads can be manufactured in order to format the tape and magnetic disks to have many data tracks at the same time at a higher speed than the usual track speed. For CD-RWs, however, heating and a certain cooling speed are required to write each pit, and the speed is essentially low. Rewritable media use a transparent, phase-change material which can change its crystalline state reversibly when heated and then cooled at a certain controlled speed. To heat the material and then cool small areas at a certain required controlled speed, a laser is used. Therefore, it takes 40 to 80 minutes to format the entire CD-RW disk irrespective of whether formatting is performed by the medium manufacturer or in a drive. As a result, formatted CD-RWs may be very expensive for users. When the user needs to record data immediately, however, it may not be commercially acceptable that the drive apparatus of the user requires a period of 40 to 80 minutes for formatting a disk. Therefore, it is generally required that drive apparatuses partially format CD-RWs at a high speed in order to provide the usability of giving an initial state at a high speed and incremental recording of recording additional data.
As data recording methods for optical disks, such as write-once disks (CD-Rs) in which data is recordable, and rewritable disks (CD-RWs) into which data is again recordable in an overwriting manner, a track-at-once method and a packet-write method are used.
In the track-at-once method, data is recorded in a track at a time with one packet. User data blocks are continuous in the track, and a link block is not disposed between user data blocks. This track serves as a recording unit. Up to 99 tracks can be formed on a disk. Table-of-contents information (TOC), such as the starting address and the ending address of a track, is stored in an area different from that for recording user data.
In contrast, a track is divided into a plurality of packets, and data is recorded in units of packets in the packet-write method. Since data is recorded in units of packets, user data blocks are disposed in a discrete man
Shishido Yukio
Tsukatani Shigeki
Udagawa Osamu
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