Classifications

• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
  • G11B20/10—Digital recording or reproducing
  • G11B20/18—Error detection or correction; Testing, e.g. of drop-outs
  • G11B20/1883—Methods for assignment of alternate areas for defective areas
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
  • G11B20/10—Digital recording or reproducing
  • G11B20/18—Error detection or correction; Testing, e.g. of drop-outs
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
  • G11B20/10—Digital recording or reproducing
  • G11B20/18—Error detection or correction; Testing, e.g. of drop-outs
  • G11B20/1879—Direct read-after-write methods
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
  • G11B20/10—Digital recording or reproducing
  • G11B20/12—Formatting, e.g. arrangement of data block or words on the record carriers
  • G11B20/1217—Formatting, e.g. arrangement of data block or words on the record carriers on discs
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
  • G11B20/10—Digital recording or reproducing
  • G11B20/18—Error detection or correction; Testing, e.g. of drop-outs
  • G11B20/1883—Methods for assignment of alternate areas for defective areas
  • G11B2020/1896—Methods for assignment of alternate areas for defective areas using skip or slip replacement to relocate data from a defective block to the next usable block, e.g. with a primary defect list [PDL]
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B2220/00—Record carriers by type
  • G11B2220/20—Disc-shaped record carriers

Definitions

• the present invention relates to the field of defect management on recording media, and more particularly, to a high density write-once recording medium that allows defect management via a slipping replacement in a defective region while performing recording in a verify-after-write mode, and a defect management method and apparatus.
• defect management schemes using linear replacement and slipping replacement algorithms have been used.
• a defect management method using linear replacement when a defect occurs in a sector in a recording area while the media is being used, the defective sector is replaced with a sector from a spare area.
• the linear replacement algorithm is used for the recording media that allows repeated recording but is not usable as a real-time recording format.
• a defective sector is skipped and data start being recorded on the next available sector. That is, if defects are found in one area, subsequent data is recorded in an area after a corresponding number of defective sectors have been skipped.
• defects are checked for upon initialization of media and a logical sector address for recording user data is not assigned to defective sectors, so that the defective sectors are unavailable for use.
• the method using slipping replacement is used to skip over defective sectors found upon initialization of media or before Use after checking for defects.
• the defect management using linear replacement has a problem in that it can not be used for write-once recording media which do not support random access. Also, the method using slipping replacement cannot be used as is for write-once recording media since the recording medium on which data cannot be erased/re-recorded once written cannot perform certification for checking for any defects before use.
• CD-R Compact Disc-Recording
• DVD-R Digital Versatile Disc-Recording
• the high density write-once recording media provide recording capacity up to tens of gigabytes (GBs) in the same size as the existing media at an affordable price. Furthermore, since this media allow quick read speed and random access unlike backup media such as tapes, they can used, in particular, as backup to large capacity computer storage devices. However, this media have a drawback that, in the case of requiring a batch backup during nighttime when not much users do not access the system, backup is not executed and ceases to operate upon occurrences of a defect during the backup. Disclosure of the Invention
• the present invention provides a high density write-once recording medium allowing a defect management.
• the present invention also provides a high density write-once recording medium that allows for a defect management using slipping replacement in a defective region while data are recorded in a verify-after-write mode.
• the present invention also provides a defect management method in which slipping replacement is used for a defective region while data is being recorded on the high density write-once recording medium in a verify-after-write mode.
• the present invention provides a defect management apparatus which uses slipping replacement for a defective region while data is being recorded on the high density write-once recording medium in a verify-after-write mode.
• a high density write-once recording medium In the high density write-once recording medium, data is written in predetermined recording units, the data is verified after writing, no data is written on a defective portion if a defect is found therein, and data corresponding to the defective portion and the following written data are rewritten on a next available recording location.
• the predetermined recording unit is a track comprised of a predetermined number of clusters or a cluster.
• a defect management method used for a high density write-once recording medium.
• the method includes the steps of: writing data in predetermined recording units and verifying the written data; and skipping a defective portion if a defect is found during the verification and rewriting data corresponding to the defective portion and the following written data on a next available recording location.
• the predetermined recording unit is a track comprised of a predetermined number of clusters or a cluster.
• a recording/reproducing apparatus for performing defect management for a high density write-once recording medium, the apparatus having a driver that drives the recording medium, an optical pickup that reads/writes data from the recording medium by irradiating laser beams onto the recording medium, and a signal processor that modulates data into a signal for recording data and demodulates a recorded signal back to the original data.
• the apparatus also includes a controller that controls the operation of verifying data, which has been written in predetermined recording units to a recording area on the recording medium through the signal processor and the optical pickup and read through the optical pickup and the signal processor after the data have been recorded, and if a defect is found, the controller controls the operation of skipping a defective portion and rewriting data corresponding to the defective portion and subsequently written data to a next available recording location on the recording medium through the signal processor and the optical pickup.
• the apparatus further includes a memory that temporarily stores information about the skipped defective portion and subsequently written data.
• FIG. 1 shows a schematic example for illustrating a defect management method in which slipping replacement is used while data is being recorded on a high density write-once recording medium in a verify-after-write mode
• FIG. 2 shows another schematic example for illustrating a defect management method in which slipping replacement is used while data is being recorded on a high density write-once recording medium in a verify-after-write mode
• FIG. 3 is a flowchart showing a defect management method for a high density write-once recording medium according to an embodiment of this invention
• FIG. 4 shows the configuration of a recording/reproducing apparatus for performing defect management for a high density write-once recording medium according to an embodiment of this invention.
• slipping replacement can be used instead of linear replacement that is suitable for recording media that allow repeated recording.
• data is recorded in a verify-after-write mode which requires that after a portion of data has been written the recorded portion should be verified. If it turns out that the corresponding portion of data has been normally recorded, the next portion of data is then recorded. If the portion of data is found to contain a defective portion, the defective portion is skipped by slipping replacement and data corresponding to the defective portion and data recorded on the following portion are rewritten to the next available region.
• the portion of data is written in a predetermined recording unit.
• the predetermined recording unit can be one track corresponding to the number of clusters that can be recorded during one revolution of the disc or one cluster.
• FIG. 1 shows a schematic example for illustrating a defect management method for a high density write-once recording medium, in which slipping replacement is used while data is being recorded in a verify-after-write mode. Particularly, this example shows a case where data is written on one recording track and read back for verification.
• This defect management method using slipping replacement while performing a verify-after-write mode in tracks minimizes the distance covered by a pickup allowing high speed recording, whereas it decreases the efficiency of use for user data area since data recorded after a defective cluster need to be rewritten.
• the unit in which data can be processed is divided into a sector and a cluster.
• the sector is the smallest unit in which data can be managed in a computer file system or application program
• the cluster is the smallest unit in which data can be written on the disc at a time.
• one cluster is comprised of one or more sectors. Sectors are classified into physical and logical sectors.
• a physical sector refers to a space for recording one portion of data on the disc, and for addressing purposes is assigned a separate physical sector number (PSN).
• a logical sector refers to a unit in which data can be managed in a file system or application program, and is assigned a separate logical sector number (LSN).
• a recording/reproducing apparatus for recording/reproducing data on a disc uses a physical sector number to locate data to be recorded, and a computer or application program for recording data manages the entire data by logical sectors and the location of data by specifying LSNs.
• a controller in the apparatus converts relationship between LSN and PSN using the presence of defects and the location where recording starts.
• one recording track is comprised of a predetermined number of clusters, each cluster having k sectors.
• information about the skipped clusters is stored in a temporary storage memory in the recording/reproducing apparatus.
• this method has no substantial advantages in that it not only requires information about the defective cluster, a new recording area where the defective cluster is recorded, and normal clusters residing between the defective cluster and new recording area, but also requires complicated processing for the recording/reproducing apparatus to read the data thus recorded.
• FIG. 2 shows another schematic example for illustrating a defect management method for a high density write-once recording medium, in which slipping replacement is used while data is being recorded in a verify-after-write mode. Particularly, this example shows a case where data is written in clusters and read back for verification.
• This defect management method using slipping replacement while performing a verify-after-write mode in clusters increases the use efficiency of user data area but slows down the recording speed.
• a method of repeating verify-after-write operation by clusters involves jumping back to the original track in order to read back and verify the written cluster because data is read from or written to a rotating disc by laser beams.
• this method decreases the recording speed by the time taken for the disc to rotate from the beginning of the original track till the cluster recorded within the track.
• this approach also makes it possible to skip only the defective clusters, thereby increasing the efficiency of use for user data area.
• a method of repeating the verify-after-write operation by tracks increases the writing speed by writing and verifying clusters corresponding to one track during the same period of time necessary to perform verify-after-write operation for one cluster.
• this approach involves rewriting the defective cluster as well as all subsequently recorded clusters in order to maintain the sequential order of logical sector numbers of the recorded data, thereby decreasing the efficiency of use for data recording areas.
• To increase the writing speed it is possible to write two or more tracks at the same time.
• this method cannot increase the writing speed much since it will simply reduce the time by the difference between the time taken to perform one track jump backward for all tracks and that taken to perform jump backward for all tracks in units of two or more tracks.
• FIG. 3 is a flowchart showing a defect management method for a high density write-once recording medium according to an embodiment of this invention.
• the defect management method includes the steps of: writing user data in one recording unit - one track or one cluster (S101 ); jumping back to the original track (S102); verifying the data written on the track (S103); determining whether there is a defect in the recorded data (S104); and rewriting the defective cluster and all following clusters of data on the next available area if the defect is found (S105).
• step S105 in the case of performing verify-after-write for each track as shown in FIG.
• the defective cluster and all subsequent clusters are skipped and corresponding data are rewritten on the next available track.
• verify-after-write for each cluster as shown in FIG. 2
• only the defective cluster is skipped, and data corresponding to the defective cluster is rewritten on the next available cluster. If no defect is found in the step S104, a verify-after-write operation is repeated in tracks or clusters in the step S 106.
• FIG. 4 shows the configuration of a recording/reproducing apparatus for performing defect management for a high density write-once recording medium according to an embodiment of this invention.
• the recording/reproducing apparatus consists of a driver 20 for driving a disc 10, that is, a recording medium, an optical pickup 30 that reads/writes data from/to the disc 10 by irradiating laser beams onto the disc 10, a signal processor 40 that modulates data onto a signal for recording data and demodulates a recorded signal back to the original data, a controller 50 that controls each block, and a memory 60 that temporarily stores data to be recorded and records information necessary for defect management.
• data to be recorded received for recording through the controller 50 is written to the disc 10 through the signal processor 40 and the optical pickup 30, and a location on the disc 10 where data is written is adjusted by the driver 20.
• the controller 50 controls the location where data is written and the amount of data.
• the written data is read through the optical pickup 30 and the signal processor 40 according to the control by the controller 50.
• the controller 50 compares data read from written area with currently written data residing in the memory 60, and if a defect is found, the controller rewrites a defective cluster and subsequently written data to a new recording area on the disc 10 through the signal processor 40 and the optical pickup 30, and records information about the defective cluster and subsequently written data on the memory 60 which is a temporary storage area. After the verify-after-write operation is performed sequentially to write all data to be recorded, under the control of the controller 50, the information about defects stored in the memory 60 is read and written to a predetermined area on the disc 10 through the signal processor 40 and the optical pickup 30.
• this invention applies a defect management method to a high density write-once recording medium, using slipping replacement while data is being recorded in a verify-after-write mode, thereby allowing continued recording by slipping defects found in the recording medium and further increasing the reliability of the recording medium. Furthermore, when a high density write-once recording medium is used for batch backup in a large-capacity computer storage device, a defect management method using slipping replacement according to this invention enables the recording medium to execute seamless backup even when defects occur in the recording medium, thereby preventing a backup operation from being interrupted. That is, this eliminates the need to restart a backup operation or replace the recording medium with a new one, thus enhancing the reliability of the system.

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• Engineering & Computer Science (AREA)
• Signal Processing (AREA)
• Signal Processing For Digital Recording And Reproducing (AREA)
• Optical Recording Or Reproduction (AREA)

Applications Claiming Priority (3)

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• 2002
  • 2002-08-12 KR KR1020020047515A patent/KR20040015425A/ko not_active Application Discontinuation
• 2003
  • 2003-06-03 TW TW092115027A patent/TW200403661A/zh unknown
  • 2003-06-05 EP EP03730893A patent/EP1550123A4/de not_active Withdrawn
  • 2003-06-05 AU AU2003241200A patent/AU2003241200A1/en not_active Abandoned
  • 2003-06-05 CN CNB038190028A patent/CN100452224C/zh not_active Expired - Fee Related
  • 2003-06-05 JP JP2004527407A patent/JP2005535992A/ja active Pending
  • 2003-06-05 PL PL03375215A patent/PL375215A1/xx not_active Application Discontinuation
  • 2003-06-05 WO PCT/KR2003/001113 patent/WO2004015707A1/en active Application Filing

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