JP2008015739A - Backup method and device of av content - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form back-up data of a target content stored in a network system. <P>SOLUTION: The network system has at least three devices each of which has one memory. An auxiliary content is searched. The auxiliary content is stored in a device other than a device where the target content is stored. The auxiliary content has a data size equal to or greater than the data size of the target content. Exclusive OR operation is taken between bits of the target content and the auxiliary content, and parity data is generated as a result of the exclusive OR operation. The generated parity data is stored in a device which is other than the devices where the target content or the auxiliary content is stored. A target content back-up note which contains information of location of the auxiliary content and location of the parity data is generated. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a backup method and apparatus for AV content, and more specifically, a method for improving the reliability of AV content by selecting a content pair in a heterogeneous home network device to which various devices are connected. Relates to the device.

  Recent advances in networking technology have enabled communication capabilities in various devices. Consumer electronic (CE) devices with digital content manipulation capabilities employ communication capabilities for content mobility. For example, the presence of wired and wireless communications, which is the 802.11 family, allows AV content to be easily moved between CE devices and to other conventional network devices.

  Home networks have provided the freedom to move content between devices to support the needs of all users. Personal devices (eg, digital cameras, portable AV players, etc.), home devices (eg, DVD recorder / player, AV stereo system, TV, PC, etc.) and mobile devices (cell phones, wireless notebooks, etc.) The containing home device is connected to a home network system (such as a LAN) so that AV data or text data from one home device can be transferred to another home device. This allows AV content to be moved seamlessly between devices over the Internet, mobile network, home network, or between devices over other networks. For example, a movie broadcast can be recorded on a CE device and stored on another storage device that can later be streamed on another display device for playback over a home network. Alternatively, MP3 songs can be purchased by download over the Internet or mobile network, stored on the home storage device, and played at a convenient time. There are stationary and mobile CE devices in the home network. The stationary device is always connected to a network such as a DVD recorder / player, an AV stereo system, a TV, and a PC. On the other hand, the movable device is always in a moving state. Network connectivity is ad hoc based. These movable devices include, but are not limited to, digital cameras, portable AV players and mobile phones.

  AV content in the home network is managed in a distributed manner without interruption. In homes, storage of AV content is indispensable because there are multiple CE devices that have different purposes but mostly have digitization capabilities and related operability. These devices have general-purpose functions such as generation, storage, re-purpose and use of AV content. These functions may be enabled to run locally or on different devices that exist in the home network.

  AV content generation functions include content download, live recording and copying at or from other devices. Storage generally refers to storage of content at either a single location or a distributed location on the home device. Repurposes include activities that can be performed remotely on the device, such as editing and generating AV content, or on other devices with special functions. Use refers to a playback function of AV content that can be executed locally or remotely. For example, a DVD recorder connected to a TV can be used to record a live broadcast stream / movie to a home storage device coupled to a network. This movie can later be edited on a PC and played on a TV or PDA with network streaming from a home storage device.

  AV content stored in a device such as a DVD player or a television receiver may be damaged by, for example, a device failure. In order to save the AV content from such damage, it is preferable to back up the AV content. An example of taking a backup is disclosed in Patent Document 7 that introduces a RAID system. RAID schemes use sophisticated steps to create backup data, but such backup data can be enormous in size.

  Accordingly, it is an object of the present invention to provide a self-managing, simple and reliable scalable AV content backup system that has less storage space.

Disclosure of information on prior art documents
T.A. Outside Shuichi “Method and apparatus for simultaneously transferring data from local storage medium to remote storage medium, and method and system for managing data transfer from source storage medium to repository storage medium” US2004 / 0158582 A1, U.I. S. Cl. 707 / 104.1, August 12, 2004. S. C. Richard et al. “Efficient method for distributing and managing content in distributed tiers of storage devices based on rules” US Pat. No. 6,772,209 B1, U.S. Pat. S. Cl. 709/225, August 3, 2004. H. Masaki et al. “File management device and method, and audiovisual data recording / purpose changing device and method” US Pat. No. 6,694,339 B1, U.S. Pat. S. Cl. 707/203, February 17, 2004. Y. S. Outside Siew, “Method and apparatus for initializing new nodes in a network” US 2003/0046369 A1, 709/220, March 6, 2003. M.M. P. Sujal, “Systems and Methods for Providing a Distributed File System Incorporating Virtual Hot Spares” US 2003/0135514 A1, U.S. Pat. S. Cl. 707/102, July 17, 2003. T.A. F. William et al., “Systems and Methods for Transparent Expansion and Management of Online Electronic Storage,” US 2004/0078542 A1, U.S. Pat. S. Cl. 711/172, April 22, 2004. S. S. W. Peter et al. “RAID Method and Device with Network Protocol between Controller and Storage Device” US 6,834,326 B1, U.S. Pat. S. Cl. 711/114, December 21, 2004. C. P. Outside Eric "Computer Systems and Processes for Transferring Data Streams between Multiple Storage Units and Multiple Applications in a Scalable and Reliable Way" US 6,785,768 B2, US 2002/0162047 A1, US 6 760, 808 B2, U.S.A. S. Cl. 711/112, August 31, 2004. T.A. K. Ryuta "System for storing data and method for controlling the writing of redundant data" US 6,813,685 B1, U.S. Pat. S. Cl. 711/114, November 2, 2004. U. S. Thomas "Distributed recording method in which necessity of transition from first recording apparatus to second recording apparatus is broadcast by first recording apparatus" US 6,859,846 B2, U.S. Pat. S. Cl. 710/8, February 2, 2005. L. Darryn, “Method for managing item storage across a network of heterogeneous storage devices” US 2005/0021915 A1, U.S. Pat. S. Cl. 711/154, January 27, 2005. M.M. Rowen “Systems and Methods for Time-Dependent Data Storage and Recovery” WO 2005/031576 A2, Apr. 7, 2005. M.M. T.A. Thomas et al., “Systems and Methods for Transmitting Data Using Virtual Streaming in Computer Systems” US 2005/0108414 A1, U.S. Pat. S. Cl. 709/231, May 19, 2005. J. et al. D. Lawrence “Data Redundancy Scheme and Device” US 2003/0196023 A1, U.S. Pat. S. Cl. 711/1, October 16, 2003. W. R. Steven et al. “Virtual File System” US 2005/0114350 A1, U.S. Pat. S. Cl. 707/10, May 26, 2005.

  The present invention relates to the reliability of AV content by content-aware pairing in a heterogeneous home network device. In particular, the present invention provides a heterogeneous home network device for managing the reliability of AV content by performing content-aware pairing on the network for seamless AV content search and playback. Provide a method and system.

The system has an intelligent mechanism for obtaining variable network information that detects demands for storage reliability of AV data and determines one or more locations where reliability data needs to be generated and stored. The data for reliability generation may be either fully available or partially available AV content that requires parity generation when a storage request is made. If there is any repetitive content in the home network, such content may be removed for space optimization.
Based on the above information, an appropriate primary storage device with an associated processor and other possible storage devices with an associated processor are selected. Content pairing is performed against the AV content that can use the closest match in a heterogeneous network environment for a new partial or full AV stream, using the exclusive OR method. The resulting parity data is stored on the primary device and one or more storage devices are used if the situation requires. Similarly, when a search request for AV parity data is detected, related information is collected and information related to parity data distribution of AV content is provided to the user. Sufficient resources are also accumulated in the home CE device, and smooth parity / data distribution of AV contents is enabled. When the parity data distribution of the AV content is completed, the reliability service status is notified to all related devices.

  Information collected from network CE devices is used to determine which device or devices are used for parity data generation in a heterogeneous network environment. If there is a change or data alteration during the AV content search, the parity content is used to play the AV content in a heterogeneous network CE device environment. The present invention also discusses content-aware pairing techniques related to parity data storage space efficiency.

  Embodiments of the invention are supplemented by the drawings that illustrate the invention with reference to particular figure elements. Iterative examples are encompassed by the specific examples covered by specific diagram elements.

  The present invention describes a method and system for AV content reliability through content pairing in a home heterogeneous CE network device. These CE devices may be devices of the same purpose, similar purposes or different purposes, each including but not limited to text files, image files, audio files and audio video files. It has its own dedicated processor for processing AV content. There will be static and mobile CE devices in the home network. Static devices are always connected and do not move much. In contrast, some devices are always on the move and network connectivity is ad hoc based.

  AV content storage that may be partially or fully available in a distributed storage environment requires content reliability. AV content on the home CE device may be distributed in a distributed manner as a partial stream that is virtually similar to a full stream that the user makes maximum use of storage. In some cases, full AV content may be stored on a single device. Normally, CE devices at home are not always fully utilized, and therefore processing resources including CPU resources are left unused. Even if the processing capability of the CE device is relatively low, it is possible to generate sufficient processing capability for content reliability activities if these multiple CE devices are combined via a network. This ensures the reliability of AV content that is distributed in addition to fully utilizing these enormous processing resources in the home environment.

  However, the unpredictable behavior and behavior of CE devices interferes with the ongoing process of AV content reliability-related activities. CE device processing resources are typically reserved exclusively for user-specific needs and scheduled tasks. For example, the processing resources of a DVD recorder / player are used for AV playback and scheduled AV stream recording. The processing resources of the processing unit can be used for other purposes including parity generation only when the DVD recorder / player is not used. In another example, some CE devices are mobile and can join and leave the home network ad hoc. In such a case, the processing resources of the CE device are unpredictable. The mobility may be due to either power unavailability or device unplugging from the home network. These operations can be presented as notified operations or non-notified operations that need to be managed to fully utilize the available processing resources of the CE device at home.

  The present invention is for AV content reliability activities, including parity data storage and retrieval at home, parity generation with content parity, AV content reconstruction and AV parity update to improve AV content reliability. Furthermore, the present invention relates to a system that uses processing resources of a CE device at home and a method for using the system.

(First embodiment)
A first embodiment of the present invention is shown in connection with FIGS. 18A, 18B, 19A, 19B, 20 and 21. FIG.

  Referring to FIG. 18A, a process for obtaining parity data Z using target content X and auxiliary content Y is shown. The target content X stored in the memory X is a movie such as “third man” that the user desires to take backup data. It is assumed that the data size of the target content X is 50 MB. The auxiliary content Y, which is data to be paired with the target content X for the purpose of backup, can be any type of data, but has a data size equal to or larger than the data size of the target content X It is preferable that the video data has The auxiliary content Y is stored in a memory Y different from the memory X. For example, the auxiliary content Y is a movie such as “Star Wars” having a data size of 100 MB.

  In general, if the user desires to store or back up the target content X, the auxiliary content Y has a size larger than the target content X and is stored in a memory other than the memory in which the target content X is stored. Another content is searched for. Next, an exclusive OR operation is performed between the target content X and the auxiliary content Y for all the bits in the target content X. More specifically, exclusive OR processing is performed between the first bit of the target content X and the first bit of the auxiliary content Y, and the result is stored as parity data Z in the memory Z. The second bit of both is then processed and repeated until the final bit of the target content X is reached. Therefore, the exclusive OR operation is executed from the first bit to the last bit for the target content X and from the corresponding first bit to the intermediate bit for the auxiliary content Y. Therefore, the parity data Z has the same data size as the data size of the target content X. The parity data Z is stored in a memory other than the memory in which the target content X and the auxiliary content Y are stored. The backup data of the target content X is parity data Z and auxiliary content Y. This is because these two data, Y and Z, are used to reconstruct the target content X.

  It is assumed that the target content X is damaged and cannot be recovered by itself. In such a case, the target content X is completely erased, and the new target content X is reconstructed using the parity data Z and the auxiliary content Y. Next, this will be described.

  Referring to FIG. 18B, a process for reconstructing new target content X is shown. The exclusive OR operation is obtained between the parity data Z and the auxiliary content Y from the respective leading bits. More specifically, exclusive OR processing is performed between the first bit of the parity data Z and the first bit of the auxiliary content Y, and the result is reconstructed in the memory X as the target content X Stored. This is then repeated until the last bit of parity data Z is processed, the second bit of both being processed. Therefore, the exclusive OR operation is executed from the first bit to the last bit for the parity data Z and from the corresponding first bit to the intermediate bit for the auxiliary content Y. In this way, the new reconstructed target content X is stored in the memory X.

  The above calculation is automatically executed as described below.

  Referring to FIG. 19A, a home network is shown. The home network comprises devices A, B, C, and D, which by way of example are a first video recorder, a first television receiver, a second video recorder and a second television receiver, respectively. . Each device has a CPU and a memory. Memory A of device A stores content A, memory B of device B stores content B, memory C of device C stores content C, and memory D of device D stores content D. . Further, it is assumed that the user desires to take backup data of the content A that is the target content. When the backup data of content A is requested, a series of steps shown in FIG. 20 are executed.

  In step S1, device A broadcasts the information of target content A including the data size via the home network and is equal to or larger than the data size of target content A in memories B, C and D. Look for auxiliary content with data size.

  In step S2, devices other than device A look for content that satisfies the required data size in each device. As a result of the search, it is detected that devices B and C each include content B and C that satisfy the required data size.

  In step S <b> 3, the devices B and C send information about the content stored in each device to the device A.

  In step S4, device A searches for and selects one content that best fits the required data size. This can be done by selecting content that is closer to the data size of the target content and that has a larger data size. Such a selection can be done by checking the length of the playback time of a video program such as a movie or a show so that content having a playback time approximately the same as the playback time of the target content is selected as auxiliary content. , May be achieved. Here, it is assumed that content B is selected as auxiliary content. Further, in step S4, device A detects the current operating status, ie the load on devices A and B, eg whether the device is recording or whether the device is playing. If it is detected that some operation is being performed on device A or B, device A waits until its load is reduced or terminated.

  In step 5, device A sends a data transfer request to device B so that it can begin sending content B of device B to device A when the detected load drops to an appropriate low level.

  In step S6, the device B sequentially transmits the content B from the memory B to the memory A, for example, in packets.

  In step S7, the device A performs an exclusive OR operation between the target content A and the auxiliary content B to obtain parity data. After generating the parity data, the device A broadcasts information on the parity data including the data size to devices other than the device B in which the auxiliary content is stored via the network, and stores the parity data. Find a memory with enough free area.

  In step S8, each device other than device B checks an empty area in the memory. Here, it is assumed that the device D has a sufficient empty area.

  In step S <b> 9, the device D sends to the device A information regarding sufficient free space in the memory.

  In step S10, device A detects the operating status, ie the load on devices A and D, eg whether the device is recording or whether the device is playing. If it is detected that some operation is being performed on device A or D, device A waits until its load is reduced or terminated.

  In step S11, when the detected load falls to an appropriate low level, device A starts transmitting parity data sequentially from memory A to memory D, for example, in packets.

  Therefore, after step S11, the parity data is stored in the memory D of the device D as shown in FIG. 19B. In this case, the backup data of the target content A is established by a combination of the auxiliary content B in the memory B and the parity data in the memory D.

  In step S12, the device A includes target content A information (position and size, etc.), auxiliary content B information (position and size, etc.), and parity data information (position and size, etc.). Generate backup notes. The target content backup note should include at least the location of the auxiliary content and the location of the parity data. Such target content backup notes are stored in the device A in the form of a reliability file table (RFT), and the target content A is stored in the memory A in the device A. The reliability file table will be described in detail in the second embodiment.

  Referring to FIG. 21, a series of steps for reconstructing the target content A is shown.

  When the target content A in the device A is damaged, the target content A reconstruction operation is performed as shown in FIG.

  First, device A reads a backup note stored in device A, and detects the positions of auxiliary content B and parity data. In this case, it is detected that the auxiliary content B exists in the device B and the parity data exists in the device D.

  In step S <b> 21, device A sends a transfer request for auxiliary content B from memory B to memory A to device B.

  In step S <b> 22, device A sends a transfer request for parity data from memory D to memory A to device D.

  In step S23, the device D transmits the parity data from the memory D to the memory A in a packet or the like.

  In step S24, the device B transmits the auxiliary content B from the memory B to the memory A in a packet or the like. The transmission of parity data and auxiliary content B may be in the opposite order or interleaved.

  In step S25, the device A performs an exclusive OR operation between the parity data and the auxiliary content B to generate the reconstructed target content A.

(Second Embodiment)
FIG. 1 shows a home network sample 102 that connects CE devices A 104a, B 104b, and C 104c via a network, such as 802.11 / Ethernet, which is either wired or wireless. Each of these CE devices has its own storage unit 106a, 106b and 106c combined and processing unit 112a, 112b and 112c. These CE devices may have different adaptability, device configuration and operability at home, and may have different functions and purposes.

  The storage unit includes both AV content 108a, 108b and 108c and AV parity data 110a, 110b and 110c for AV content. AV content 108a may be partial or full AV content local to CE device A 104a. When partial AV content is stored in CE device A 104a, full AV content can be obtained from all three CE devices 104a, 104b, and 104c via virtual AV content. Parity data generated by content pairing with an exclusive OR operation between new AV content (target content) and existing AV content (auxiliary content) is also partially or fully stored in the local storage unit. Stored in format.

  FIG. 2 in this embodiment shows communication between the software stack 202 in the processor 232 of the CE device A and the stack for AV parity data processing. The software stack can be separated as user space 210 and kernel space 212 software. The storage reliability distributed application 204 which is a user application program exists in the user space. This storage reliability distribution application 204 is an interface with users, and provides a reliability service for AV contents of all users. This application can be further divided into AV application reliability management 208 and information management 206 sub-applications.

  AV content reliability management 208 responds to operations relating to AV content reliability, and information management 206 collects information in response to communication messages and disseminates it among multiple CE devices. Information messages are necessary to make informed decisions that are crucial for AV content parity related activities.

  The system space 212 includes a distributed file system having a reliability file table 214, a local HDD driver 216, and a NetHDD driver 236. These software drivers enable communication to the actual hardware via the local HDD controller 218 and the network HDD controller 234 for storing redundant data. The parity data is stored in either the local HDD 220 or the NetHDD 224 in which the actual AV content 1 having the parity content 2 222 and the actual AV content 2 having the parity content 1 226 are stored. The redundant data 226 for the AV content 1 in the local HDD is stored in a distributed manner in the NetHDD 224 for higher reliability. Even when the local HDD 220 is inaccessible, the AV content 1 222 a can be recovered using the parity content 1 226 b in the NetHDD 224. The reliability file table 214 as part of the distributed file system is all related to AV parity data specific to any AV content stored completely or partially in the storage units 220 and 224 of the CE device. Consists of information. This file is periodically backed up in the storage unit of other CE devices for reliability related reasons. The central file exists so that all locations where the distributed reliability file table exists are stored for reliability purposes.

  The level of reliability is increased by storing reliability data in a distributed manner, not only in the same CE device A, but also in the storage units of other CE devices in the network. In order to further increase the redundancy of data, the redundant data may be generated as partial data and stored in storage units of different CE devices. The network driver 230 shown in FIG. 2 of the embodiment enables communication through the physical network layer 228 by transmitting parity data and communication messages.

  The general steps involved in the reliability service are shown in FIG. The list of available reliability services is AV content / parity storage and retrieval, AV content / parity construction by content pairing, AV content reconstruction and parity update. Parity service request 402 indicates which specific requests are intended from these four services. A request for a reliability service is triggered 402 by a detection mechanism for the reliability service. Next, the AV content information 406 is examined for selection decisions based on specific rules. In addition, information about the network is collected or updated 404 to assist in the decision making process supported by the rules. Using all available information, a determination is made 408 which CE device or devices are to be used for a particular reliability service. Finally, certain reliability operations are performed 410.

  FIG. 5A shows data collected by the communication message mechanism and supporting a decision making mechanism for selecting a CE device and AV content storage location for AV content reliability service with the assistance of rules. Information about CE devices can be classified as either static or dynamic. The static information 502 comprises the current storage size, processor ID and parity data buffer size. The processor ID is a unique ID number that can provide information, such as processor speed and number of processing threads, supported functions, and parity data buffer size, associated with the processor of the CE device.

  FIG. 5B shows AV content information that can be either static 506 or dynamic 508. The static information includes the type of AV content, the format of the AV content, the length including byte size and time, and its partial or full status specific to the CE device storage unit. The CE device and AV content information are referred to as variable network information in this embodiment.

  The CE device selection mechanism analyzes AV content information and CE device information to make a decision. Information such as that shown in tables 502, 504, 506 and 508 is used for the decision process. AV content information and CE device information are used to select a CE device processor.

  FIG. 7 illustrates the general steps involved in receiving AV parity data storage or retrieval requests. The storage reliability distribution application 204 receives 702 an AV parity data storage or retrieval request by the trigger mechanism. Next, it is checked whether either full 704 or partial 706 AV parity data is available for the store or retrieve process. Prior to storage or retrieval decision, the variable network and AV content information is referenced 708. A determination is made 708 based on predetermined rules using the collected information. This includes a check to ensure that no previous parity data was constructed for this AV content. This is done by checking the file name of the AV content. If parity data is available, the reliability file table 214 is updated accordingly.

  The primary CE device and other preferred CE devices may be detected separately by identifier for storage or retrieval operations. One or more CE devices and associated resources are accumulated 710 to perform the requested operation. Subsequently, AV content parity data is stored or retrieved 712. Finally, when the task is completed, the requester 204 is notified, the reliability file table 214 is updated, and all accumulated resources are released 714.

  As shown in the embodiment of FIG. 8, the second AV content reliability service is generation of AV content parity by content pairing. The AV content / parity generation request first receives a request 802 from the application 204. Next, the process of locating all related files is performed. First, information 506 and 508 relating to new AV content (ie, target content) for which parity generation is requested is collected 806. Based on this information, the location of the closest matching file (ie, auxiliary content) with respect to size and format is identified 808. Next, a primary CE device and other preferred CE devices are identified for parity generation operations 810. One or more CE devices and associated resources are stored 810 to perform the requested operation. The CE device selection decision is made 804 based on predetermined rules using the collected information. Subsequently, an AV content / parity generation operation is performed 812. The generated parity data is stored 814 using the process sequence described in FIG. Finally, when the task is completed, the requester 204 is notified and all accumulated resources are released 816.

  The third and fourth services include a request for reconstructing AV content and updating parity due to the user's AV content operation. FIG. 9 shows the steps necessary to achieve this goal. When AV content destruction or AV content editing is detected 902, a request to reconstruct AV content or update parity is received 904. The reliability file table 214 is used to identify 908 associated parity data. Regarding parity update, it is necessary to identify original AV content (target content), pairing content (auxiliary content), and preceding parity content. Next, a primary CE device and other preferred CE devices are identified 910 for parity generation operations, where one or more CE devices and associated resources are stored to perform the requested operation. 910. The CE device selection decision is made 906 based on predetermined rules using the collected information.

  Next, the AV content recovery process is started 912. Regarding the reconstruction of the parity data, new parity data is constructed 912 only for the AV content part for which the AV operation has been performed. When the task is complete, the reconstructed AV content and parity data are stored 914 again. If the size of the updated parity data is larger than the previous data and the current storage is insufficient to contain this new parity data, a new location is identified and the parity data is available next Stored in position. Finally, when the task is completed, the requester 204 is notified and all accumulated resources are released 916.

  The operation described above is shown in FIG. 3 of this embodiment.

  FIG. 3 shows AV content transfer 303c for parity generation, AV content / parity 303a to be transferred for storage, AV content / parity search 303b for AV content reconstruction, and reconstruction. The details of communication by the AV content / parity / data storage 303b are shown.

  The CE application 301a uses a storage detection mechanism to detect a storage event 301a. When a storage event is detected, a parity data construction mechanism is activated 302a by the CE A application. For the later process, the predetermined steps specified in FIG. 8 are used. When the related information of the new AV content (target content) X314 is recognized, the closest matching AV content (auxiliary content) 312 is determined. Based on the information collected by the message communication mechanism 301b shown in FIGS. 5A and 5B, the application of the CE device A 304 identifies one or more available target CE devices from the list of CE devices 304, 306, and 308. .

  Once the CE devices are identified, the three CE devices shown in FIG. 3 are listed using the parity service CE selection rules according to priority. As shown in FIG. 4, the CE selection rule uses information collected by the CE A application 301b for this purpose. As described in box 810 of FIG. 8, one or more CE devices are selected for a particular parity service.

  The closest matching new AV content X (target content) 314 and existing AV content Y (auxiliary content) 312 are paired and processed by an exclusive OR operation. Selection of the closest matching AV content is performed by the communication message infrastructure, and the best matching AV content is determined by the selection mechanism. As shown in FIG. 3, the closest matching AV content is stored in storage CE B and transferred to processor CE A 302b for content pairing 303c. When both contents are paired, the parity data is transferred 303a to storage CE A 302c, storage CE B 306c and storage CE C 308c as three different partial data. This will be further described in connection with FIG. The size of the partial AV parity data may be the same as or different from the size of the full virtual AV content parity data.

  If the AV content needs to be reconstructed or updated due to data loss due to user operations operating the AV content, data editing or data update, an AV content reliability service is required. For example, the reconstruction request for the AV content X 314 is detected by the CE application 306a that virtually uses the AV content. Based on the available information and the selection mechanism, the CEC processor 308b is selected by the unused processing resources. Therefore, the AV content Y312 to be paired is transferred to the CEC processor 308b together with the related parity data stored in the storage processor A302c, storage processor B306c, and storage processor C308c, 303b, and the AV content X314 is reproduced again. Built. The reconstructed AV content X314 is transferred to and stored in the CE storage 302c.

  If the new AV content X (target content) has some repetitive or non-critical data, it can be removed prior to the pairing process based on the process described in FIG. Good. Details of the repetitive content removal process will be described later.

  Similarly, in the case of AV content update, related AV content and pairing content are transferred to the CE processor having unused processing resources, and the parity is updated. Parity data of the newly constructed AV content is transferred back to the original position and replaced. If the updated AV parity data is larger than the previous content and the storage device is full, an alternate storage device is searched using the process shown in FIG.

  FIG. 6 shows possible combinations of AV content distribution locations for CE devices for reliability services. For all AV content reliability services, there are four possible scenarios for the location of AV content that is either partial or full form. The new AV content 1 (target content) that requires reliability indicated by 604, 616, 620, and 628 is designated as AV content 1 in FIG. The AV content (auxiliary content) to be paired with the closest matching is designated as AV content 2 and indicated by 608, 614, 622 and 630. An exclusive OR operation between these two AV contents generates parity data 610, 612, 624 and 632.

  In scenario 1 602, all three files are stored locally for reliability services.

  In the second scenario 618, the AV content 1 indicated at 616 is stored in the local storage unit, but the paired content 614 portion is obtained from the different distributed AV content 614 and generated parity data 612 portion. Is stored at the same location as where the paired AV content portion is found.

  In the third scenario 626, AV content 1 shown at 620 and AV content 2 shown at 622 exist within a single CE device on which a parity operation is performed. However, the generated parity data is partially stored 624 at different locations in the distributed virtual file.

  In the final fourth scenario 634, three files, namely AV content 1 shown in 628, AV content 2 shown in 630, and parity content 632 are all located in four or more different storage locations. Separated into parts.

  In all four scenarios shown in FIG. 6, AV content 1 at 604, 616, 620 and 628 may be fully available in the individual CE storage units, or the content may be moved from an external source, or In some cases, it may be partially available (gradually stored) by either real-time or recording. In the case of partially available data, content pairing is also progressively performed because most of the data is available for content pairing.

  AV content 2 can also be replaced with the closest matching parity data for exclusive OR operation. In this case, the resulting parity data is dependent on the AV content 1 and the two original AV content that generated the parity data used for content pairing.

  There are several situations where parity content storage and retrieval, parity generation, AV content reconstruction and parity update can be hindered due to the ad hoc nature of CE devices present in the home network. Or exist. These situations include storage full, interruptions due to storage or CE device disconnection or network leave and high priority task requests for immediate processing resources. These events may also be classified as notified events or classified as non-notified events.

  The notified event is a situation in which the storage reliability distribution application 204 is notified of a trend of a CE device that may perform a predetermined operation that interferes with a current operation controlled by a certain application. Say. An unreported event is a situation in which the storage reliability distributed application 204 knows that a process or task has been stopped for some reason. For notified events, the storage reliability distribution application 204 has the opportunity to reschedule its current task with minimal configuration changes to ensure that the task continues to run. However, for unannounced situations, the storage reliability distribution application 204 needs to restart the CE and restore from discontinuation before accomplishing the assigned task.

  Regarding the HDD full that is an event to be notified, the storage reliability distribution application 204 needs to find another location to store the currently processed content by adopting the process described in FIG.

  If a storage outage, CE device power off, CE device isolation, or task exchange with a high priority user task is encountered, this is a notified decision. 204 means that this trend of the CE device has been notified earlier, so the application performs the necessary steps to recover from this action of the CE device. In the case of AV parity storage, the application can decide to continuously restore all content or remaining content in another CE device storage unit. This determination can be made using steps 710, 712 and 714 shown in FIG. If the event is a data search, then the same available data must be searched if it is available, otherwise the connected CE device and until the entire AV parity content is searched Negotiations are held to continue the state.

  With respect to AV content restructuring and parity data update interruption, the storage reliability distribution application 204 has four possible scenarios that are addressed with reference to FIG. The discontinuation of use of the CE device may be responsible for possessing AV content 1 or AV content 2, storing the resulting parity data, or simply performing an exclusive OR operation. For AV content 1 and 2, content can be transferred to a new CE device to continue the reliability service. For parity content storage or exclusive OR operations, communication message support must be used to identify another available CE. This is possible using steps 710, 712 and 714 shown in FIG. 7 for parity data storage using the previously identified secondary CE device. For exclusive OR operations, steps 810, 812, 814, 816 in FIG. 8 can be used. In both the latter two cases, a pointer for which parity content storage is performed and an exclusive OR operation is performed is transferred to the CE device newly specified by the CE device for efficiency.

  If the use stop event is a non-notification event, in the case of parity storage, AV parity data needs to be stored again at different locations using steps 710, 712 and 714 shown in FIG. However, if parity data is not available in the source storage unit where it was originally constructed, a parity rebuild request must be made and the entire process shown in FIG. 8 must be repeated. In the case of parity data search, parity data can be reconstructed based on the urgency of the task if both AV content 1 and AV content 2 shown in FIG. 6 are available. If the content is not available, the storage reliability distribution application 204 is notified of service interruption and a rescheduling is proposed.

  Regarding the interruption of the parity generation service due to the unintended use stop, it is necessary to continue the whole process depending on the role of the CE related to FIG. In this case, the steps shown in FIG. 8 are used.

  With respect to AV content reconstruction and parity data update interruption, the storage reliability distribution application 204 has four possible scenarios to deal with, as shown in FIG. A CE device that is no longer used may be one that should retain AV content 1 or AV content 2, store the resulting parity data, or simply perform an exclusive OR operation. If the CE device should have one of the required AV content or parity data, the service is not recoverable. For the storage reliability distribution application 204, rescheduling of activities is recommended. If the CE device only performs content pairing operations or parity content storage, these steps can be performed using partial steps as presented in FIGS. It is possible to move to the CE.

  There is a possibility for the user to attempt to delete a file stored in the distributed file system. If a delete operation is invoked, the dependency of AV content on parity reconstruction is analyzed by examining all trusted file tables via the communication message system. Referring to FIG. 6 showing this embodiment, if the virtual or physical AV content 1 is deleted, the AV content 2 cannot be reconstructed if the parity data 610 is destroyed. In the case of such a deletion request, the AV content 1 is backed up at another location using the same steps as the steps related to the reliability of the AV content 2 in FIG.

  Another possible event is taking a backup to the selected CE device storage unit, or a hard disk drive (HDD) of the storage unit in the home network. In this case, the reliability file table 214 is examined and the backup disk is an independent unit for AV content, and all three of AV content 1 604, AV content 2 608, and parity data 610 are moved. . The reliability file table 214 needs to be updated as needed when this event occurs with the assistance of a communication message.

  Backup operations are detected and referenced by the trusted file table. The reliability file table of the storage device that requires backup of AV content is used to identify all relevant AV parity data and AV content. The identified AV content and parity data are backed up to a new storage device, ensuring that all dependent files of the AV content are also moved. This movement of AV content and parity data content needs to ensure that the backup storage reconstructs any AV content independently without reference to other networked storage units.

  The reliability file table is also periodically backed up to other CE storage devices at a predetermined time to ensure the reliability of the file table. The predetermined time may be a time when the device records low resource usage.

  FIG. 12 shows a generic reliability file table. This table refers to, for example, reliability information of all AV files that are AV content 1 604, AV content 2 608, and parity data 610 stored in a plurality of CE devices either locally or in a distributed manner. It is a main table used for storing. A generic table as shown in FIG. 12 may be used to store information on AV content, AV pairing content, and generated parity data in a distributed network environment. This generic table having a plurality of fields 1202 to 1242 is used in a selective field that stores information about three different AV contents in the CE device.

  This table has a field 1202 that indicates which specific type of content is stored in the CE device, and this field contains the AV ID, pairing AV ID, or AV parity data ID. Each specific AV ID has a plurality of fields for storing various information related to the AV. The content 1204 field contains all AV related information including AV type 1206, AV format 1208, AV length (time or duration display) 1210, AV size (byte display) 1212 and AV file specific parent or child status 1214. Hold. Types include drama, movie, documentary that can be obtained from the content type 1438 field of the event information table. Formats include mpeg, mp3, TS, PS, etc. The parent / child field refers to the relationship between distributed AV files (either AV content, AV pairing content or parity data). Only one AV file can be a parent, and the other files are children to the parent. The parent file is the first part of the AV file. The parent may be stored in the same location as the child or in a different location.

  The event classification 1216 in this table indicates all event-related information unique to a specific AV content. This section is only available for AV content 1202 and is not available for pairing AV or parity data. The information in this table is extracted from the event information table shown in FIG. The event ID 1218 indicates the event ID 1402 at the time of AV content. AV content may consist of two or more events such as an actual broadcast program, a commercial program 1440 between the actual program and the repeatability start, an end content subtype 1442 in the drama, etc. . These events are classified as event ID 1218. Each of these events can be classified as a content type / subtype by a unique ID as described in the EITs 1434 and 1442. Each content type has a unique duration 1222, start time and position 1224 as shown in the EIT of the 1410 and 1412 fields.

  A related sub-section of the same event reference information 1226 has information about the same event AV content in the home network. If there is some same event or multiple same events, the AV ID 1228 of all related events is recorded by the specific location 1230 where the AV content is stored.

  The partial AV ID 1232 field indicates a partial AV file stored in the CE device. The parent AV 1214 RFT has information about all its child AVs 1214. For child AV 1214, the RFT has a reference to parent location 1234. AV content / location 1234 describes information regarding where a specific AV is stored. The reference may be an absolute reference that is, for example, the IP address of the CE device and a network file pointer to the referenced AV file. Otherwise, the reference may be a relative reference that refers to the preceding AV data and indicates where the current AV data is stored. A plurality of partial AV data may exist depending on a specific AV ID 1232 and individual positions 1234.

  The AV content byte range 1236 stores the size of each partial AV file or data. The file / content status field 1238 describes the availability of AV data / content. For example, if the pairing AV content has been deleted, this field describes that the pairing content is not available.

  The final field is a content reliability status 1240 field, in which the content reliability status is described. This status may be in any of the situations where parity generation is in progress, completed, or stopped.

  The updating of these fields is based on AV status and is done via a messaging protocol. AV content and AV pairing content have all fields in the description table shown in FIG. 12, except for a content reliability field 1240 that is unique to AV parity data only. Therefore, the AV parity data has all the fields in the table of FIG.

  A single CE with an RFT table has different categories of AV information that are AV content, pairing content and parity data. For these three different categories of AV files, there may be one or more entries in the RFT table.

  The central file is not mobile and always resides in one of the CE devices connected to the network. This file stores information about all distributed reliability file tables. Similarly, this file is also automatically backed up to other networked CE devices for increased reliability. If the CE device's specific reliability file table (RTF) and the backed up RTF cannot be identified, this file serves as a reference point for all other CE devices.

  FIG. 13 shows a central reliability file table with all RFT references and their backup locations. This table has an RFT_ID 1302 field that points to the RFT of a particular CE device. In addition, the file size 1304 of the last backed up RFT is also displayed. The origin position 1306 displays the position of the RFT table with respect to the original RFT being backed up. The backup location 1308 field displays the location of the backed up RFT.

  FIG. 14 shows an existing prior art event information table (EIT) such as standard stream format, digital TV, digital video broadcasting, and the like. AV information fields 1402 to 1428 and 1452 are existing information in the current EIT. Two fields, a content descriptor 1430 and a series descriptor 1444 are added to this. These two fields do not exist in the current AV stream, but are required for a reliability service that is aware of AV content. The identifier length 1432 indicates the length of the descriptor field in bytes, the content type ID 1434 indicates the unique ID of the content, the text length 1436 indicates the length of the content type field in bytes, The content type 1438 indicates a content type such as drama, movie, commercial, or the like. Subtype 1440 and subtype ID 1442 may be additional information regarding content type 1438 such as start, end, etc.

  The content type 1438 field can also be used for searching or determining a pairing file for the parity generation process. A pairing file of AV content B that is not associated with AV content A in terms of content type may face the risk that the pairing file has been deleted by the user in terms of space efficiency. However, it is unlikely that the same or related content types will be deleted. Selecting a content type that is content-aware for pairing reduces the need for parity playback of AV content. For example, if the AV content in the drama series number 1 is paired with another AV content in the same series number 1, the user is unlikely to delete the series number 1. However, if the AV content in the drama series is paired with a comic, there is a higher probability that the comic can be deleted and parity playback is required.

  The series descriptor 1444 particularly relates to a series of AV contents such as dramas broadcast continuously. These types of AV content are most likely sponsored by the same sponsor company with the same start and end scenes and with repetitive commercial advertising content. In such a scenario, the start and end scenes and commercials are repetitive scenes if the series is recorded in the home network. Such repeated scenes can be removed. There are subfields, the descriptor length 1446 indicates the length of the descriptor field in bytes, the series ID 1448 indicates the ID of the series, and the program pattern 1450 field indicates the pattern of the broadcast program. , Episode number 1452 indicates the episode number of a specific broadcast.

  The content descriptor 1430 and series descriptor 1444 fields may be found in the AV stream content for reference.

  In general, when data transfer is performed between a local storage device and a networked storage device, a parity data buffer size control mechanism to optimally use the processing resources of both storage processors. Is used.

  FIG. 10 shows the SESF TS format for Blu-ray technology, in particular the BD-RE format. The TS AV stream is composed of a plurality of TS units 1002 arranged. The size of each unit is 6144 bytes. Each arranged TS stream unit consists of 32 source packets starting at source packet 0 1004 and ending with source packet 31 1010. Each source packet 1004 has a size of 192 bytes, 4 bytes for a TP_add packet header 1006, and 188 bytes for a payload 1012 called a transport packet. Generalization of the TS format can be performed such that there are 4 bytes of the header packet 1006 and 188 bytes of the payload 1012 packet that repeatedly transmits other information in the specified header payload size. .

  The transport stream may support other different formats besides the SESF 1016, such as but not limited to the constrained SESF 1032. However, the composition pattern of the general-purpose TS source packet 1004 repeats as described above. Other payloads include program map table PMT-1024, program related table PAT-1026, selection information table SIT-1028, TIP-1034, audio data 1030, video data 1018 and text based on stream type. -Data is included. The header 1006 is assumed to be important data including a unique payload such as the PMT 1024, the PAT 1026, the SIT 1028, and the TIP 1034. Audio payload, video payload and null packets 1008, 1010 and 1014 are non-critical data that may be selectively dropped based on the data being transmitted. For example, video packets with I frames are more important than P- and B-frames. Selective payload drop can reduce the overall size of the parity data based on the importance of the data during the content pairing operation. Null packets or data dropping has no effect on parity data.

  Non-critical data includes null data or packets, and video and audio payloads including B- or P-frames based on priority level setting for selective payload dropping and repetitive content sequences But this is not the case. In some instances, B-frames may be more important than P-frames. In such a case, the P-frame can be selectively dropped compared to the B-frame. In addition, priority levels such as levels 1, 2, and 3 can be set for unimportant data. Level 1 indicates a low data drop possibility, whereas level 3 is a high data drop possibility. For example, level 1 is assigned to an I-frame, level 2 is assigned to a P-frame, and level 3 is assigned to a B-frame. In this case, the B-frame has a higher probability of being dropped than the I-frame. A similar approach can be applied to other data including audio data.

  The payload may be classified as important data and non-important data for the AV stream. In another instance based on event ID 1402, if there is any event in the AV content type with repetitive content such as commercial 1438 or start and end scene 1440, this content is also dropped as shown in FIG. Also good.

  Important data is important and must be preserved during content pairing operations to ensure AV stream quality of future activities. However, non-critical data may be dropped during the content pairing operation and has little impact on the playback operation.

  As shown in FIG. 11, AV content A 1104 and AV content B 1106 having the same length, type and format are paired to generate parity data 1108. During a content pairing operation, non-critical data 1102 or content is dropped to produce smaller parity data 1108 that saves storage space. If it is necessary to store the location of non-critical data or content to be dropped for reconstruction purposes, indicator bits can be inserted between the source packet headers. For example, referring to the C-SESF format stream 1032, if the audio payload is deemed unimportant, it is dropped and an indicator bit between the two TP_add packets 1036 and 1040 that is the important data. It may be marked. The dropped payload can be easily identified using indicator bits during reconstruction or for any other purpose.

  FIG. 15 shows the details of the non-critical data or content selective dropping process. Upon receipt of non-critical data or content dropping 1502, AV content A content classification 1504 is executed and associated RFT updates as shown in FIGS. 16 and 17 are performed. Once the AV content is classified, the dropping of null data / packet 1508, repetitive AV content 1512, audio data / packet 1516, video data / packet 1518 and other data / packet 1520 is determined. Null data / packets are removed 1506, repetitive pattern content is removed 1510, audio data / packets are removed 1514, video data / packets are removed 1518, and other data / A related measure is taken to remove the packet. Optionally, an indicator bit can be inserted that indicates where the data / packet or content is dropped. Finally, content is prepared for the pairing operation.

  FIG. 16 shows the steps required to update fields 1216-1224 in the RFT. When a trigger for content classification execution of AV content A is received 1602, the EIT table from the AV stream is read 1604. The related information of EITs 1216 to 1224 is read and updated in the RFT. This information is important for content-aware specific operations.

  FIG. 17 shows the steps necessary to remove repetitive AV content and update the RFT using this indicator, if an indicator is inserted where repetitive content is removed. When a trigger for removing the repetitive pattern content of AV content A is received 1702, event ID 1218, content type ID and content subtype ID 1220 information of AV content A RFT table is read 1704. Using this information, all RFTs in the home network are searched for the same event ID, content type ID, and content subtype ID, and repetitive content is detected 1706. If there is a match, the associated AV ID 1228, its location 1230 and other relevant information is updated in the RFT. Next, repetitive content, if any, is removed 1710.

  This method of dropping selected data or content may generally be applied to BD-RE format files by content-aware pairing operations. For example, PlayList and ClipInfo files are important, so data dropping is not applicable, but content-aware pairing methods can be used for AV stream files.

  According to one theory, only 20% of content is most likely to be accessed frequently by 20% of devices in the home. Content reorganization may be performed between CE devices. Unused AV parity data 610 is moved to a CE device that is rarely selected in the selection process 710 of FIG. Other criteria include the use of CE devices with large storage space, slow network bandwidth access and fewer processing resources. This reorganization of the content is the time of the parity data that is part of the storage reliability distributed application when the CE device is not in use at home for a predetermined time as a background task, for example at night. This is done automatically by the reorganization process.

  This reorganization activity also moves the most frequently accessed parity content to CE devices that frequently access them to improve performance. In addition, the reorganization of AV parity data is also based on the date on which the trusted file table was last accessed. The most recently accessed AV parity data is given a higher priority for reorganization. The selection of the destination storage device is based on the availability of storage space at the destination storage device. Selection criteria also includes destination devices with slow network connectivity. In this case, the movement time of the AV parity data may be based on the minimum load CE processor time of both the source and destination processors.

  If there is an interruption in the reorganization of the content, activity is resumed on the basis of the last worked file recorded in the trusted file table 214. All content reorganization activities are recorded and updated in the reliability file table 214. When data is transferred between a local storage device and a networked storage device with a different CE processor speed, a parity data buffer size control mechanism is used to optimize the transfer speed. Is done.

  The present invention can be used for a content backup method and apparatus.

Fig. 3 shows a simple heterogeneous home network according to a second embodiment with multiple CE devices with unique processing and storage units with AV content and parity content. Fig. 5 illustrates communication between software stacks for reliability data storage and retrieval services. Fig. 4 shows the main communication flow for storage and retrieval of reliability data between three different CE devices. Demonstrates the main decision process of receiving reliability service requests, decision processing and taking appropriate actions. Figure 3 shows three main data sets collected for use in decision processing by storage and reliability services. Figure 3 shows three main data sets collected for use in decision processing by storage and reliability services. It shows how file pairing is performed for different combinations of new AV content 1, existing AV content 2 and resulting parity data. The main steps performed to store and retrieve AV content parity data are shown. The main steps for generating AV content parity are shown. The main steps for rebuilding parity to support data recovery or content re-editing operations are shown. Fig. 2 shows a detailed self-encoding stream format (SESF) and C-SESF of the transport stream packet structure for Blu-ray technology. A pairing operation in consideration of AV contents of two TS AV contents is shown. A generic reliability file table is shown. Figure 5 shows a backfile table with all RFT references in the home network. An event information table including event information associated with AV content is shown. Fig. 4 illustrates a drop decision process flow for selective non-critical data or content. Fig. 4 illustrates a process for updating an RFT with event information. Fig. 4 illustrates a process for updating an RFT with event information of repetitive content. 2 shows a parity data manufacturing process according to a first embodiment; FIG. 2 shows a target content reconstruction process according to a first embodiment. FIG. It is a block diagram which shows arrangement | positioning of the content backup apparatus by 1st Embodiment. It is a block diagram which shows arrangement | positioning of the content backup apparatus by 1st Embodiment. 3 is a time chart showing steps for generating backup data according to the first embodiment. 4 is a time chart showing steps for reconstructing target content using backup data according to the first embodiment.

Explanation of symbols

102... Home network 104a .. CE device A
106a, storage unit 108a, AV content 110a, parity data

Claims (22)

A content backup method for generating backup data of target content stored in a network system having at least three devices, each device having at least one memory comprising:
Searching auxiliary content stored in a device other than the device in which the target content is stored, the auxiliary content having a data size equal to or larger than the data size of the target content;
Performing an exclusive OR operation between the bits of the target content and the auxiliary content, and generating parity data as a result of the exclusive OR operation;
Storing the parity data in a device other than the device in which the target content or the auxiliary content is stored;
Generating a backup note of the target content including information on the location of the auxiliary content and the location of the parity data,
Thereby, the auxiliary content and the parity data are used for the backup data of the target content.   The content backup method according to claim 1, wherein the searching step searches for auxiliary content by checking a reproduction time length of the content.   2. The target content backup note further includes location information of the target content, data size information of each of the target content, the auxiliary content, and the parity data. The content backup method described.   The content backup method according to claim 1, wherein the exclusive OR operation is performed in a device storing the target content.   The content backup method according to claim 1, further comprising: storing the generated target content backup note in a device in which the target content is stored.   The content backup method according to claim 1, further comprising: detecting a current operation state of the device in which the target content is stored and the device in which the auxiliary content is stored.   The content of claim 1, further comprising: checking for an empty area in a device other than the device in which the target content is stored and the device in which the auxiliary content is stored to store the parity data. -Backup method.   The method of claim 1, further comprising: detecting a current operating state of a device in which the target content is stored and a device for storing the parity data.   The content backup method according to claim 1, further comprising: reconstructing new target content using the parity data and the auxiliary content. The rebuilding step is
Reading a backup note of the target content to find the location of the parity data and the auxiliary content;
Performing an exclusive OR operation between the parity data and the bits of the auxiliary content to generate new reconstructed target content;
10. The content backup method according to claim 9, comprising storing the new reconstructed target content on a device in which the original target content is stored. A content backup apparatus for generating backup data of target content stored in a network system having at least three devices, each device having at least one memory,
Means for searching auxiliary content stored in a device other than the device in which the target content is stored, the auxiliary content having a data size equal to or larger than the data size of the target content;
Means for performing an exclusive OR operation between the bits of the target content and the auxiliary content, and generating parity data as a result of the exclusive OR operation;
Means for storing the parity data in a device other than the device in which the target content or the auxiliary content is stored;
Means for generating a backup note of the target content including information on the location of the auxiliary content and the location of the parity data,
As a result, the auxiliary content and the parity data are used for backup data of the target content.   12. The content backup apparatus according to claim 11, wherein the searching means searches for auxiliary content by checking a reproduction time length of the content.   12. The target content backup note further includes location information of the target content, data size information of each of the target content, the auxiliary content, and the parity data. The content backup device described.   The content backup apparatus according to claim 11, wherein the exclusive OR operation is performed in a device that stores the target content.   12. The content backup apparatus according to claim 11, further comprising means for storing the generated target content backup note in a device in which the target content is stored.   12. The content backup apparatus according to claim 11, further comprising means for detecting a current operation state of a device in which the target content is stored and a device in which the auxiliary content is stored.   12. The content of claim 11, further comprising means for checking an empty area in a device other than the device in which the target content is stored and the device in which the auxiliary content is stored in order to store the parity data. Backup device.   12. The content backup apparatus according to claim 11, further comprising means for detecting a current operation state of a device in which the target content is stored and a device for storing the parity data.   The content backup apparatus according to claim 11, further comprising means for reconstructing a new target content using the parity data and the auxiliary content. The above reconstruction means is
Means for reading a backup note of the target content to locate the parity data and the auxiliary content;
Means for performing an exclusive OR operation between the parity data and the bits of the auxiliary content to generate new reconstructed target content;
20. The content backup apparatus according to claim 19, comprising means for storing the new reconstructed target content in a device in which the original target content is stored.   A program for executing the method according to claim 1.   A computer-readable recording medium in which the program according to claim 21 is stored.

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