Patent Publication Number: US-2003227846-A1

Title: Recording medium for storing write protection information, and recording method and write protection method thereof

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001] This application claims the benefit of Korean Patent Application No.  2002-31995 , filed on Jun. 7, 2002 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.  
       BACKGROUND OF THE INVENTION  
       [0002] 1. Field of the Invention  
       [0003] The present invention relates to a multi-layer recording medium which includes a plurality of recording layers and stores write protection information necessary to prevent recording, a method of recording write protection information, and a write protection method thereof.  
       [0004] 2. Description of the Related Art  
       [0005] Optical disc techniques widely used in the field of computers and electric home appliances have advanced in pursuit of high-density and high-speed access. In particular, there has been developed next generation high-density discs of 23 GB capacity using a blue laser.  
       [0006] In order to improve the recording capacity, the development of a disc structure having a plurality of recording layers is in progress. Also, in view of a next generation high-density writable and rewritable disc, there is a need for a user to be able to effectively protect data recorded on a plurality of recording layers and in recordable zones in each of the plurality of recording layers from overwriting.  
       SUMMARY OF THE INVENTION  
       [0007] Accordingly, the present invention provides a multi-layer recording medium, which stores write protection information for protecting the multi-layer recording medium from overwriting, a method of recording write protection information, and a write protection method thereof.  
       [0008] The present invention also provides a multi-layer recording medium capable of selectively protecting every recording layer from overwriting, and a recording method and a write protection method thereof.  
       [0009] The present invention also provides a multi-layer recording medium capable of selectively protecting every recording zone from overwriting, and a recording method and a write protection method thereof.  
       [0010] Additional 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.  
       [0011] According to an aspect of the present invention, a multi-layer optical recording medium includes writable or rewritable recording layers, where each of the layers includes a lead-in zone, a lead-out zone, and a data zone, the multi-layer optical recording medium stores write protection information for selectively protecting data recorded on the multi-layer recording medium from overwriting.  
       [0012] According to an aspect of the invention, the write protection information selectively protects each of the plurality of writable or rewritable recording layers or every recording zone.  
       [0013] According to another aspect of the present invention, a method of recording data on a multi-layer optical recording medium having a plurality of writable or rewritable recording layers, where each of the layers includes a lead-in zone, a lead-out zone, and a data zone, where write protection information for selectively protecting data recorded on the multi-layer recording medium from overwriting is recorded, the method includes recording write protection information for selectively protecting each of the plurality of writable or rewritable recording layers and recording write protection information for selectively protecting each recording zone in each of the plurality of writable or rewritable recording layers.  
       [0014] According to still another aspect of the present invention, a write protection method of protecting data recorded on a multi-layer optical recording medium including a plurality of writable or rewritable recording layers, where each of the layers has a lead-in zone, a lead-out zone, and a data zone, from overwriting, the method including checking write protection information recorded on the multi-layer optical recording medium, and selectively preventing the data from being recorded on the multi-layer optical recording medium according to the checked write protection information.  
       [0015] According to an aspect of the invention, the selectively preventing data from being recorded on the multi-layer optical recording medium includes preventing the data from being recorded on each of the writable or rewritable recording layers according to the write protection information and/or in each recording zone according to the write protection information.  
       [0016] The write protection information recorded on the multi-layer optical recording medium and a write protection state of a case including the multi-layer optical recording medium are checked. If the write protection information is not consistent with the write protection state of the case, a user is informed of the inconsistency. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0017] The above and/or other features and advantages of the present invention will become more apparent and more readily appreciated by describing in detail exemplary embodiments thereof with reference to the accompanying drawings of which:  
     [0018]FIG. 1 shows a recording medium having a multi-layer structure according to an embodiment of the present invention;  
     [0019]FIG. 2 shows the multi-layer structure of the recording medium shown in FIG. 1;  
     [0020]FIG. 3 shows the structure of a zone in which write protection information is stored according to an embodiment of the present invention;  
     [0021]FIG. 4 shows the data structure of the write protection information shown in FIG. 3;  
     [0022]FIG. 5 shows a recording medium in which only a user data zone of a layer  1  is protected from recording by write protection information according to an embodiment of the present invention; and  
     [0023]FIG. 6. shows an embodiment of a recording and/or reproducing apparatus for use with the recording medium of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS  
     [0024] 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.  
     [0025] For high-density recording, a next generation high-density disc may include a plurality of recording layers or a single layer. However, in the example of the present invention shown in FIG. 1, the next generation high-density disc includes two representative layers: a layer  0  and a layer  1 . The layer  0  includes a lead-in zone LI formed at the inner perimeter of the layer  0 , a lead-out zone LO formed at the outer perimeter of the layer  0 , and a user data zone formed between the lead-in zone LI and the lead-out zone LO. The layer  1 , considering a recording direction according to a laser beam, includes a lead-out zone LO formed at the inner perimeter of the layer  1 , a lead-in zone LI formed at the outer perimeter of the layer  1 , and a user data zone formed between the lead-in zone LI and the lead-out zone LO of layer  1 . Thus, assuming that data is recorded starting from the user data zone after the lead-in zone LI at the inner perimeter of the layer  0 , after the recording of data in the user data zone in the layer  0  is finished and additional recording is to be performed, the data is recorded starting from the user data zone in front of the lead-in zone LI of layer  1 .  
     [0026]FIG. 2 illustrates the structure of the recording medium shown in FIG. 1 according to an embodiment of the present invention. Here, only the layer  0  is shown, but the layer  1  also has the same structure as the layer  0 . Referring to FIG. 2, the layer  0  is divided into three sections according to its function: a lead-in zone, a user data zone, and a lead-out zone.  
     [0027] The lead-in zone may be divided into an unrecordable zone and a recordable zone according to its physical characteristics. In particular, the lead-in zone has a reproduction only lead-in zone in which recording is impossible, a rewritable lead-in zone, and a connection zone of a wobble or mirror form therebetween. The reproduction only lead-in zone may exist in a wobble form such as a groove track of a high frequency, or in a pit form. The reproduction only lead-in zone has a disc-related information zone in which a disc type, a disc size, a version number, recording conditions, and so forth can be stored, and a zone in which other pieces of information can be stored. The rewritable lead-in zone includes a buffer, a test zone for optimal power control (OPC) fit for the recording conditions, a disc control data zone, a reserved zone, a defect management zone, and a buffer. The user data zone and the lead-out zone have rewritable zones. The lead-out zone includes a buffer, a test zone, a disc control data zone, a reserved zone, a defect management zone, and a buffer.  
     [0028] Here, the disc control data zone, the defect management zone, and the reserved zone in each of the rewritable lead-in zone and the lead-out zone are each shown as one zone in FIG. 2. However, preferably, there are a plurality of zones that are physically separated from each other in order to guard against being rendered unusable due to errors on the disc.  
     [0029]FIG. 3 illustrates the structure of a zone in which write protection information is stored according to an embodiment of the present invention. The write protection information may be recorded in any of the recordable zones except the user data zone shown in FIG. 2. For instance, the write protection information is stored in the disc control data zone or the reserved zone in the rewritable lead-in zone of the lead-in zone, or the disc control data zone or the reserved zone of the lead-out zone.  
     [0030] Referring to FIG. 3, 1-byte write protection information is stored in a first byte (BPO) of the disc control data zone or the reserved zone, and the remaining bytes are reserved. For the safety and reliability of information, it is preferable, but not necessary that the write protection information is recorded multiple times on a disc. The write protection information may be recorded at either the inner or outer perimeter of the disc, but preferably, is recorded at both the inner and outer perimeters of the disc. Thus, the write protection formation is recorded in the disc control data zones or the reserved zones in the rewritable lead-in zone and the lead-out zone. In a case where a plurality of disc control data zones or reserved zones are physically separated from each other in each of the rewritable lead-in zone and the lead-out zone, it is preferable that the same write protection information is recorded multiple times. Here, the write protection information is recorded multiple times because zones in which the write protection information is recorded may not be used or data can be only read from and not recorded in the zones due to errors generated in the zones. Thus, the write protection information may be incorrectly read and the disc may operate abnormally so as to not permanently record data thereon and allow accidental overwriting.  
     [0031]FIG. 4 illustrates the data structure of the 1-byte write protection information shown in FIG. 3. Write protection information is recorded, according to an aspect of the invention, in a first byte of a disc control data zone or a reserved zone ( i.e., in a 0-btye position). However, it is understood that other locations could be used or later developed. The 1-byte write protection information is defined as follows.  
     [0032] bits b 7  to b 6 : these bits are Reserved and are set to 00  
     [0033] bits b 5  to b 0 : specify the write protection information  
     [0034] b 5 , b 3 , and b 1  specify write protection on the entire  
     [0035] disc (layers), layer  0 , and layer  1 , respectively.  
     [0036] 0b: Not write protected.  
     [0037] 1b: Write protected.  
     [0038] b 4 , b 2 , and b 0  specify write protection on a specific area  
     [0039] 0b: Every area is write protected.  
     [0040] 1b: User data area is write protected.  
     [0041] In other words, according to the above embodiment, bit positions  7  b 7  and  6  b 6  of the write protection information are reserved and may be set to “00”. Bit positions  5  b 5 ,  3  b 3 , and  1  b 1  indicate whether the entire disc (layers), a layer  0 , and a layer  1 , respectively, are write protected so as to selectively protect all or individual recording layers from recording. If each bit position value is “0b”, writing is not protected. If each bit position value is “1b”, writing is prevented. Bit positions  4  b 4 ,  2  b 2 , and  0  b 0  indicate whether specific zones are write protected and may selectively protect zones of each layer from recording. If each bit position value is “0b”, writing is not protected. If each bit position value is “1b”, writing is protected.  
     [0042] While two recording layers, (i.e., a layer  0  and a layer  1 ), and write protection information for protecting all zones or user data zones from recording are described herein, it is understood that additional recording layers may be further included and that the write protection information for selectively protecting recording layers and minute zones from recording may be recorded thereon.  
     [0043]FIG. 5 illustrates a recording medium in which only a user data zone of a layer  1  is write protected by write protection information according to another embodiment of the present invention. 1-byte write protection information is recorded as “00000011b” in a disc control data zone or a reserved zone. Since bit position  1  (b 1 ) is “1b”, bit position  1  (b 1 ) indicates that the layer  1  is write protected. If bit position  0  (b 0 ) is “1b”, bit position  0  (b 0 ) indicates that only the user data zone is write protected.  
     [0044] Referring to FIG. 5, let us assume that data is recorded starting from the user data zone after a lead-in zone LI at the inner perimeter of a layer  0  by a laser beam. Then, after recording data in the user data zone in the layer  0 , even if recording is desired to continue, a user data zone (marked with slanted lines) before a lead-in zone LI at the outer perimeter of the layer  1  is write protected by write protection information stored in the disc control data zone or the reserved zone. Therefore, the user data zone is write protected.  
     [0045] Accordingly, a write protection method according to the present invention includes checking write protection information recorded on a multi-layer recording medium and selectively preventing data from being recorded on the multi-layer recording medium according to the checked write protection information. It is understood that the method being performed could be performed using a controller to control an optical pickup for use in recording and/or reproducing data with respect to the disc shown in FIG. 1 using the laser beam. The controller could be implemented as a computer, either a general purpose of a special purpose computer, which implements the method as computer software stored on a computer readable medium.  
     [0046] A disc is sometimes in a cartridge state in which the disc is mounted in a case. However, a bare disc is also often used. When a disc in a case is used, data recorded by a user can be protected from overwriting using a write protection hole formed in the case. Specifically, in order to write protect the disc within the case, the write protection hole is switched from a closed state indicating the “disc is not write protected” to an open state indicating the “disc is write protected”, so that a recording apparatus does not perform a writing operation on a write protected disc. However, when a bare disc state without a case is used, the disc itself must protect data recorded by the user from overwriting. To this end, the above-described write protection information according to the present invention is proposed. When a bare disc is put into a case in which a write protection hole is set to a recordable state so that the bare disc is used in a cartridge or a disc is put into a case in which a write protection hole is set to a write protection sate, write protection information recorded on the disc may be inconsistent with the state of the write protection hole of the case so as to cause a conflict.  
     [0047] In case of conflict between the write protection states indicated by the case and the bare disc, if either the disc or the case is write protected, a user receives a warning message providing an opportunity to check the states of the disc and the case, and the disc is preferably treated as being write protected. This is because it is safer to not record data until the contents of the already recorded data are checked one more time, rather than risking the possibility of overwriting data by mistake. It is understood that the recording and/or reproducing apparatus can implement the warning message using a display connected to or controlled by the apparatus, using audible warnings, light indicators, and other similar mechanisms by which a user is informed.  
     [0048]FIG. 6 shows a recording and/or reproducing apparatus according to an embodiment of the invention. A controller  120  controls an optical pickup  130  to record and/or reproduce data with respect to the disc  100 . The optical pickup  130  has a light source to produce the laser beam. A display  140  is controllable by the controller  120  so as to display messages, such as a warning message.  
     [0049] As described above, according to the present invention, data recorded on a disc can be effectively protected from overwriting by recording write protection information for selectively protecting every recording layer and/or every recording zone of a multi-layer recording medium from overwriting.  
     [0050] Also, when only one of a case and a disc indicates that the disc is write protected, a user can be informed of the write protection state and thus have an opportunity to check the states of the disc and the case to resolve the conflict. As a result, data recorded on the disc can be stably protected.  
     [0051] While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims and their equivalents.