Patent Publication Number: US-2006007826-A1

Title: Recording/reproducing apparatus, recording/reproducing method and information storage medium using the same

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
      This application claims the benefit of Korean Application No. 2004-54096, filed Jul. 12, 2004, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.  
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      An aspect of the present invention relates to a disk, and, more particularly, to an apparatus and method of recording data on an optical recording information storage medium, an apparatus and method of reproducing data from an optical recording information storage medium, and an optical recording information storage medium using the same.  
      2. Description of the Related Art  
      A characteristic of write-once information storage media is that overwriting recorded data is impossible. Accordingly, only some recording methods may be used, such as disc at once recording or sequential recording in track units.  
       FIG. 1  illustrates a file system recording method in a write-once information storage medium  100  according to the prior art.  
      For example, in the conventional write-once information storage medium  100 , data may be written as shown in  FIG. 1 . That is, a file system  110  is written on a first location of the write-once information storage medium  100 , and if first data  120  is written on the next location after the file system  110 , a modified file system  130  which reflects the new recording situation is written on the next location after the first data  120 . Likewise, if second data  140  is written on the next location after the file system  130 , a modified file system  150  which reflects the new recording situation is written on the next location after the second data  140 . In the conventional write-once information storage medium  100 , information of the file system is dispersed to a plurality of locations, which slows reproduction.  
      In general, two types of command are used to write data on an information storage medium. One is a simple data write command, and the other is a verify-after-write command, which asks for verification after the writing, to ensure a reliability of data. The latter is performed for data such as file system data, for which data reliability is essential since the entire medium cannot be reproduced if the file system data is corrupted. General data, on the other hand, is only damaged in file units if a defect is generated. Therefore, the verify-after-write command substantially guarantees the reliability of data by a use of a defect management method when the reliability of data is degraded through the verification process after the writing.  
      However, when a host tries to update data of an area already written on a write-once information storage medium, achieving this aim with only the two commands is difficult. Therefore, a method is required in which a data updating operation in a write-once information storage medium may be performed as would be performed for a rewritable information storage medium.  
      Such a method is a logical overwrite method. In the logical overwrite method, data recorded in the write-once information storage medium is updated using a defect management scheme.  
      The logical overwrite method reduces the disk lifetime, due to fast exhaustion of an information area for managing the logical overwrite method.  
     SUMMARY OF THE INVENTION  
      An aspect of the present invention provides a recording apparatus and method to extend a lifetime of a disk, a reproducing apparatus and method to extend a lifetime of a disk, and an optical write information storage medium using the same.  
      According to an aspect of the present invention, there is provided a recording apparatus to write data on an information storage medium, the apparatus comprising: a write unit which writes data on the medium; and a controller which controls the write unit to compress temporary disk management information (TDMI), which manages the medium, and writes the compressed TDMI in a disk management area.  
      The compressed TDMI may exclude a temporary disk definition structure (TDDS).  
      The controller may separately compress each item of information included in the TDMI.  
      The controller may exclude header information when the TDMI is compressed.  
      According to another aspect of the present invention, there is provided a reproducing apparatus to reproduce data from an information storage medium, the apparatus comprising: a read unit which reads data from the medium; and a controller which decompresses temporary disk management information (TDMI) written on the medium when the data written on the medium is reproduced, and uses the decompressed TDMI for the data reproduction.  
      According to another aspect of the present invention, there is provided an information storage medium in which temporary disk management information (TDMI) is compressed and written in a disk management area.  
      Additional and/or other aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      These and/or other aspects and advantages of the invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:  
       FIG. 1  illustrates a file system recording method in a write-once information storage medium according to the prior art;  
       FIG. 2  is a schematic block diagram of a recording/reproducing apparatus according to an embodiment of the present invention;  
       FIG. 3A  is a detailed block diagram of the recording/reproducing apparatus shown in  FIG. 2 ;  
       FIG. 3B  is a detailed block diagram of a DSP shown in  FIG. 3A ;  
       FIG. 4  shows the structure of a disk to which an embodiment of the present invention is applied;  
       FIGS. 5A through 5D  illustrate disk areas related to a recording operation using a logical overwrite according to an embodiment of the present invention;  
       FIGS. 6A and 6B  illustrate a defect list according to an embodiment of the present invention;  
       FIG. 7  shows the detailed structure of a TDDS according to an embodiment of the present invention;  
       FIG. 8A  shows the detailed structure of a TDFL according to an embodiment of the present invention;  
       FIG. 8B  shows a data structure of a TDFL entry according to an embodiment of the present invention;  
       FIG. 9  is a flowchart illustrating a recording method according to an embodiment of the present invention; and  
       FIG. 10  is a flowchart illustrating a reproducing method according to an embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS  
      Reference will now be made in detail to the present embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below in order to explain the present invention by referring to the figures.  
      Due to a logical overwrite on a write-once information storage medium, a temporary defect list (TDFL) increases in size and needs to be updated frequently. Therefore, a lifetime of a disk is decreased as a result of an exhausting of a temporary disk management area (TDMA) relatively fast. To resolve this problem, disk management information is compressed when the disk management information is written. By writing the compressed disk management information, the area required for writing may be reduced so as to increase a number of possible writes for the same area and increasing the disk lifetime. The compression of the disk management information includes compression of the TDMI, and particularly, compression of the TDFL.  
       FIG. 2  is a schematic block diagram of a recording/reproducing apparatus  200  according to an embodiment of the present invention.  
      Referring to  FIG. 2 , the recording/reproducing apparatus  200  includes a write/read unit  220  and a controller  210 . Under the control of the controller  210 , the write/read unit  220  writes data on a disk  230 , which is an information storage medium according to the present embodiment, and reads data to reproduce the recorded data. The controller  210  controls the write/read unit  220  to write data in blocks of a recording unit according to the present embodiment, or obtains valid data by processing read data using the write/read unit  220 .  
      In a recording operation, the controller  210  controls the write/read unit  220  to write data by performing logical overwrite according to the command of a host  240  or the control of the drive system itself. The logical overwrite means that an updating operation of the data written on the disk  230  is performed by a disk defect management method of managing defects generated on the disk  230 .  
      The disk defect management method is a method of managing defects on a disk so as to increase the reliability of data written to the disk, including a slipping replacement method to process the defect detected in an initializing process for using the disk, and a linear replacement method to replace an ECC block unit including a defective sector with a defectless ECC block in a spare area with respect to the defect generated during use of the disk.  
      The slipping replacement method minimizes the decrease of recording or reproducing speed due to a defect by not assigning logical sector numbers to a defected sector detected in a verifying process to examine the defect of a disk when the disk is initialized, assigning the logical sector numbers of the defected sector to a subsequent sector of the defected sector by slipping the defected sector, and recording or reproducing data by neglecting and slipping the defected sector when a write or read operation is performed.  
      However, for a defect generated during use of a disk, the slipping replacement method cannot be used since a file system rule is violated due to discontinuity of logical sector numbers that is generated when a defected sector is neglected and slipped. When a defect is generated during use of a disk, the linear replacement method of replacing an ECC block including a defected sector by an ECC block in the spare area is used.  
      The controller  210  may use any one of the defect management methods to perform the logical overwrite. However, in an embodiment of the invention, the linear replacement method is used. A detailed description will be given later.  
      In a reproducing operation, the controller  210  controls the write/read unit  220  to read data according to the file system recording method used for the disk  230 . That is, the controller  210  controls the write/read unit  220  to read defect list information stored on the disk  230 , find the physical location at which the data is stored, and read the data at that location.  
       FIG. 3A  is a detailed block diagram of the recording/reproducing apparatus  200  shown in  FIG. 2 .  
      Referring to  FIG. 3A , a disk drive includes a pickup  250  as the write/read unit  220 . The disk  230  is accessed by the pickup  250 . The disk drive also includes a host interface (I/F)  211 , a digital signal processor (DSP)  212 , a radio frequency amplifier (RF AMP)  213 , a servo  214 , a system controller  215  and a memory  216  as the controller  210 .  
      In a recording operation, the host I/F  211  receives data to be updated and a replacement enforcement write command according to an embodiment of the present invention, with logical address information of the data to be updated, together from the host  240 , and transmits them to the system controller  215 . According to an embodiment of the invention, the replacement enforcement write command may be issued by the system controller  215 .  
      The system controller  215  receives the replacement enforcement write command from the host I/F  211  and performs initialization required to write data to the disk  230 . In particular, according to the present embodiment, the system controller  215  analyzes the received replacement enforcement write command and controls other units to perform the writing based on the received command. That is, if the received command is the replacement enforcement write command, the system controller  215  controls the DSP  212  and the servo  214  to seek the address of an area in which the data to be updated is written, i.e. an unused area, and to write the received data to be updated at that address. After the data to be updated is written, the system controller  215  controls the DSP  212  and the servo  214  to generate a defect list and write the defect list to the disk  230 . The defect list includes information on the physical address at which the data to be updated was first written (information on the physical address at which data was first written even if the data has been updated several times by the replacement enforcement write command) and information on the physical address at which the data to be updated is currently written.  
      According to the replacement enforcement write command, when data is updated, information on the data may be obtained at a fixed location, as in a rewritable information storage medium, by preparing a table to manage changed physical addresses without changing the logical addresses of the data.  
      The DSP  212  adds additional data, such as parity bits to correct errors to the data to be written, received from the host I/F  211 , and generates an ECC block, which is an error correction block. The DSP  212  generates the ECC block by ECC encoding the data and by modulating the generated ECC block. The RF AMP  213  converts the data output from the DSP  212  to an RF signal. The pickup  250  writes the RF signal output from the RF AMP  213  on the disk  230 . The servo  214  receives a command required for a servo control from the system controller  215  and servo-controls the pickup  250 .  
      In particular, according to the present embodiment, the DSP  212  includes an encoder to compress temporary disk management information (TDMI), since a limited amount of TDMA space is quickly exhausted and the disk lifetime is reduced due to an increase of the size of the TDFL by performing the logical overwrite on the write-once information storage medium, and due to the frequent updating of the TDFL requested by a change of the defect list caused by the logical overwrite.  
      In a reproducing operation, the host I/F  211  receives a reproduction command from the host  240 . The system controller  215  performs initialization required for the reproducing operation. In particular, according to the present embodiment, the system controller  215  controls the pickup  250  to read the area of the disk  230  in which the defect list is written, obtains information on the physical location at which data is written from the defect list, and reproduces the data from that physical location.  
      The pickup  250  radiates a laser beam on the disk  230  and receives the reflected laser beam to obtain an optical output signal. The RF AMP  213  converts the optical signal output from the pickup  250  to an RF signal, provides modulated data obtained from the RF signal to the DSP  212 , and provides a servo signal for control obtained from the RF signal to the servo  214 . The DSP  212  demodulates the modulated data and outputs data obtained through ECC error correction.  
      The servo  214  performs the servo control of the pickup  250  based on the servo signal that is received from the RF AMP  213  and the command required for the servo control received from the system controller  215 . The host I/F  211  transmits the data received from the DSP  212  to the host  240 .  
       FIG. 3B  is a detailed block diagram of the DSP  212  shown in  FIG. 3A . Referring to  FIG. 3B , the DSP  212  includes a modulator/demodulator  310 , an interleaver/deinterleaver  320 , an ECC encoder/decoder  330 , a scrambler/descrambler  340  and a TDMI compression encoder/decoder  350 . When the TDMI is compressed and stored on the disk  230 , the TDMI is compressed by the TDMI compression encoder/decoder  350 , scrambled by the scrambler/descrambler  340 , ECC-encoded by the ECC encoder/decoder  330 , interleaved by the interleaver/deinterleaver  320 , modulated by the modulator/demodulator  310 , and stored on the disk  230 . When the compressed TDMI is read from the disk  230 , the compressed TDMI is demodulated by the modulator/demodulator  310 , deinterleaved by the interleaver/deinterleaver  320 , ECC-decoded by the ECC encoder/decoder  330 , descrambled by the scrambler/descrambler  340 , decompressed by TDMI compression encoder/decoder  350 , and stored in an internal memory.  
      Compression methods used by the TDMI compression encoder/decoder  350  may include Run Length Encoding (RLE) and Huffman coding. Either a lossy or lossless compression scheme may be used, but in an embodiment of the invention, lossless compression is used for the TDMI since the TDMI is important for reproducing other data.  
      In general, in order to easily seek the final TDMI, the TDMA is continuously used due to the characteristics of the write-once information storage medium in which data cannot be overlapped.  
      When the TDMI is compressed, in an embodiment of the invention, data obtained by excluding the temporary disk definition structure (TDDS) from the TDMI is compressed.  
      In general, the size of the TDMI is variable, to cause an increase in the number of updating counts of the TDMI. If the entire TDMI is compressed, then, since the size of the TDMI cannot be known, reproduction of the final TDMI is difficult for the drive system. In addition, since the TDDS includes location pointers that direct the locations at which disk management information, including the TDMI is written, the drive system must first reproduce the TDDS to obtain the disk management information. In general, for the write-once information storage medium, due to a continuous use of the TDMA and a writing of the TDDS in a final recording block, the drive system may easily seek the TDDS later by accessing the final recording block in the TDMA. However, when the entire TDMI is compressed, if the compressed TDMI is comprised of a plurality of blocks, that the TDDS is written in the final block cannot be guaranteed. Thus, the drive system must first reproduce the entire TDMI so as to obtain the TDDS. A problem then occurs when reproducing the TDDS since the drive system cannot recognize the size of the TDMI.  
      In addition, according to an embodiment of the invention, each item of information of the TDMI is compressed separately. That is, according to the embodiment of the invention, the TDFL, a space bit map (SBM), and recording management information are compressed separately. In this case, if the size of each compressed item of information is not a multiple of a block or sector unit, the size of each compressed item of information is made to be a multiple of the block or sector unit by adding dummy data such as “00h”.  
      If the only information that requires an update so as to efficiently use the TDMA is actually updated, for example, if an update of the TDFL is required and the recording management information and the SBM do not have to be updated, the TDMA may be efficiently used by updating only the TDFL and the TDDS including location information of the TDFL. In addition, the TDDS includes information on each location pointer of the TDMI and the size of each compressed item of information. According to an embodiment of the invention, the information on the size of each compressed item of information is in block or sector units.  
      When each item of information included in the TDMI is compressed, in an embodiment of the invention, each item of information, from which header information of each of the items of information is excluded, is compressed. For example, when the TDFL is compressed, only TDFL entry information that is obtained by excluding header information from the TDFL is compressed.  
      An identifier may be stored at a specific location of a header of each item of information. The identifier determines which information a reproduced block is from the header information before each item of information is decompressed when each item of information is reproduced. For example, for the TDFL, a TDFL identifier is stored at a specific location of a TDFL header. When a compressed TDFL is reproduced from a TDFL location pointer which the TDDS directs, before the compressed TDFL is decompressed, the drive system may quickly recognize that the TDFL is reproduced from the TDFL identifier that is stored at the specific location of the TDFL header. This is due to the fact that header information is usually only a few bytes.  
       FIG. 4  shows the structure of a disk to which an embodiment of the present invention is applied. Referring to  FIG. 4 , the structure of data written on the write-once information storage medium  400  includes a lead-in area  410 , a data area  420  and a lead-out area  430 . The lead-in area  410  includes a disk management area  411  and a TDMA  412 . The TDMA  412  is an area for recording information on temporary defect management and temporary disk management to manage the write-once information storage medium. The TDMA  412  includes a TDFL  440 , a temporary disk definition structure (TDDS)  450  and an SBM  460  in the case where a recording mode is a random recording mode. The TDMA  412  includes the TDFL  440 , the TDDS  450  and recording management information  470  in the case where the recording mode is a sequential recording mode.  
      The TDFL  440  includes a defect list comprised of defect state information, location information of a defect sector, and location information of a replacement sector. According to the present embodiment, the location information of a defect sector indicates the physical location at which pre-updated data is initially written. The location information of a replacement sector indicates the physical location at which updated data is written.  
      The TDDS  450  includes location pointers of the TDFL  440 , the SBM  460  and a drive area, and further includes location and size information of spare areas that are assigned in an initializing operation, write protection information, location and size information of a temporary defect management area assigned in the data area  420 , information on a user data area  422 , information on a replaceable location in each spare area, and a last recording address in the user data area  422 . The SBM  460  is a map indicating whether each cluster of the user data area  422  is recorded using a bit value.  
      The recording management information  470  represents a data recording state as entry information by dividing the user data area  422  into several areas, similar to that of the SBM  460 . The entry information includes state information, start address information and last address information. Information on an area designated by the entry information is a recording state map of the user data area  422 , represented as the state information of the area. The state information includes information on whether data is written in the area and whether the area is available.  
       FIGS. 5A through 5D  illustrate disk areas that are related to a recording operation using the logical overwrite according to an embodiment of the present invention. In these examples, file system data is logically overwritten. However, it is understood that the present invention is not limited to the embodiments illustrated in these FIGS., and may be equally applied to general user data.  
       FIG. 5A  shows an initial file system written by assigning a file system  510  to manage user data to a fixed location, which is the beginning location of a user data area.  
      As shown in  FIG. 5B , if first data  520  is recorded in the user data area, the file system  510  is modified. Thus, file system data is updated. In response to the command of a host or the control of the drive system itself, an updated file system  530  is recorded a second spare area by the linear replacement method, as in the method in which the file system  510  is replaced due to a defect. Here, in a defect list, location information of the file system  510  and location information of the file system  530  are recorded.  
      As shown in  FIG. 5C , if second data  540  is recorded in the user data area, a file system  550  updated by the host or the drive system is recorded in the second spare area by the linear replacement method. Here, in the defect list, only the location information of the file system  510  and the location information of the file system  550  are recorded.  
      As shown in  FIG. 5D , if updated second data  560  is recorded in the user data area, an updated file system  570  is recorded in a first spare area by the linear replacement method. Here, in the defect list, only the location information of the file system  510  and the location information of the file system  570  are recorded. The defect list will be described in more detail.  
       FIGS. 6A and 6B  illustrate the defect list according to an embodiment of the present invention. Examples of the defect list recorded by a control of the controller  210  will be described with reference to  FIGS. 6A and 6B . For example, assuming that physical sector numbers of the user data area corresponding to logical sector numbers 00h to FFh are 100h to 1FFh (a recording area of the file system  530  of  FIG. 5A ), and data corresponding to the logical sector numbers 00h to FFh is updated in physical sector numbers 11FFFh to 11F00h of the spare area (a recording area of the file system  530  of  FIG. 5B ) by the host or the drive system, a defect list  610  including defect sector information and replacement sector information is shown in  FIG. 6A .  
      After the defect list  610  is made, if data corresponding to the logical sector numbers 00h to FFh is updated in physical sector numbers 11EFFh to 11E00h of the spare area, defect sector information and replacement sector information of a defect list  620  is shown in  FIG. 6B . Therefore, the last file system may be found using the fixed logical sector numbers by seeking the last defect list  620  including last physical sector numbers corresponding to the logical sector numbers. Likewise, by updating a file system using the disk defect management method when data is updated, the address of the file system may be obtained at a fixed location by fixing logical sector numbers of file system data.  
       FIG. 7  shows the detailed structure of a TDDS according to an embodiment of the present invention. Referring to  FIG. 7 , the TDDS includes information on a TDFL, information indicating the compression method, and byte-unit size information after each TDMI is compressed.  
      In an embodiment of the invention, the byte-unit size information after each TDMI is compressed is either: 1) information obtained by adding the byte size of the TDFL and the byte size of the compressed TDFL entries, or 2) the byte size of the compressed TDFL entries. In other words, the byte-unit size information after each TDMI is compressed does not include dummy data such as 00h to make the size of the TDFL a multiple of the size of a sector, since decompression cannot be performed without the actual size of the compressed data.  
       FIG. 8A  shows the detailed structure of the TDFL according to an embodiment of the present invention. Referring to  FIG. 8A , the TDFL includes a TDFL header to identify the TDFL, a compressed TDFL entry list, and dummy data such as 00h to make the size of the TDFL a multiple of the size of a sector. The compressed TDFL entry list is a list of TDFL entries. The TDFL is constituted of n sectors, wherein n is an integer.  
       FIG. 8B  shows a data structure of a TDFL entry according to an embodiment of the present invention. Referring to  FIG. 8B , each TDFL entry #i includes a defect block address and a replacement block address. For example, the defect block address indicates the physical sector number of a defect block, and the replacement block address indicates the physical sector number of a replacement block.  
       FIG. 9  is a flowchart illustrating a recording method according to an embodiment of the present invention. Referring to  FIG. 9 , when initialization is performed, a system controller generates a TDMI for initialization according to an initialization command of a host or the drive system, in operation  910 , and if an update of the TDMI is requested by performing addition of data or a logical overwrite, the system controller updates the TDMI stored in an internal memory of the drive system in operation  920 . The updated TDMI is compressed in operation  930 . The compressed TDMI is scrambled, ECC-encoded, interleaved, and modulated, in operation  940 . The modulated TDMI is recorded in a TDMA on a disk in operation  950 .  
       FIG. 10  is a flowchart illustrating a reproducing method according to an embodiment of the present invention. Referring to  FIG. 10 , a last (compressed) TDMI recorded in a TDMA is read from the disk in operation  1010 . The read (compressed) TDMI is demodulated, deinterleaved, ECC-decoded, descrambled, and decompressed, in operation  1020 . The decompressed TDMI is stored in an internal memory of the drive system in operation  1030 . Data is reproduced with reference to the decompressed TDMI stored in the internal memory, in operation  1040 .  
      The above embodiments have been described with reference to a write-once information storage medium, but the present invention is not limited to this type of information storage medium. Even for rewritable information storage media, the rewriting count is limited to a certain degree since repeated rewriting degrades data reliability. In this case, after many rewrites, data may be recorded using a replacement request write command according to an embodiment of the present invention, though a component such as a rewriting counter is required. Though file system data is described as updated data in embodiments of the present invention, it will be understood by those of ordinary skill in the art that a recording method according to an embodiment of the present invention can also be applied to user data without being limited to the file system data.  
      The embodiments of the present invention may be written as computer programs and may be implemented in general-use digital computers that execute the programs using a computer readable recording medium. Examples of the computer readable recording medium include magnetic storage media (e.g. ROM, floppy disks, hard disks, etc.), optical recording media (e.g. CD-ROMs, DVDs, etc.), and storage media such as carrier waves (e.g. transmission through the internet). The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion.  
      As is described above, according to embodiments of the present invention, all or part of a write-once information storage medium may be used as a rewritable information storage medium by updating data according to a defect management method, and in particular, the lifetime of the disk may be extended.  
      Although a few embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.