Abstract: A method for automatically generating a semantic mapping for a relational database RDB includes obtaining a first semantic mapping from a first RDB to an ontology of linked data; obtaining a schema mapping from the first RDB to a second RDB; and generating a second semantic mapping from the second RDB to the ontology of the linked data based on the first semantic mapping and the schema mapping.

Abstract: A method for automatically generating a semantic mapping for a relational database RDB includes obtaining a first semantic mapping from a first RDB to an ontology of linked data; obtaining a schema mapping from the first RDB to a second RDB; and generating a second semantic mapping from the second RDB to the ontology of the linked data based on the first semantic mapping and the schema mapping.

Abstract: Data re-protection in a distributed replicated data storage system is disclosed. The method may be implemented on a server or controller. A method includes storing first data in a first zone and storing a replica of the first data in a second zone. The zones are at different, separate locations. When an actual or impending failure with the first data in the first zone is detected, the system automatically initiates transitioning to a copy of impacted data at the first zone obtained from the second zone. The transitioning includes creating a remote copy of the impacted data at the second zone within a local area network before transferring the copy to the first zone over a wide area network. The methods allow the system to return to a fully protected state faster than if the impacted data was transferred from the second zone to the first zone without making a copy at the second zone.

Abstract: Provided are a computer program product, system, and method for recovering a volume table and data sets from a corrupted volume. Data corruption is detected in a volume having data sets. A volume table having information on the data sets allocated in the volume is diagnosed. A backup volume table comprising a most recent valid backup of the volume table is accessed from a backup of the volume in response to determining that the diagnosed volume table is not valid. Content from the backup volume table is processed to bring to a current state in a recovery volume table for a recovery volume. The data sets in the volume are processed to determine whether they are valid. The valid data sets are moved to the recovery volume. A data recovery operation is initiated for the data sets determined not to be valid.

Abstract: Embodiments relate to providing error recovery in a storage system that utilizes data redundancy. An aspect of the invention includes monitoring plurality of storage devices of the storage system and determining that one of the plurality of storage devices has failed based on the monitoring. Another aspect of includes suspending data reads and writes to the failed storage device and determining that the failed storage device is recoverable. Based on determining that the failed storage device is recoverable, initiating a rebuilding recovery process of the failed storage device based on determining that the failed storage device is recoverable and restoring data reads and writes to the failed storage device upon completion of the rebuilding recovery process.

Abstract: For preventing data loss in storage systems, a detection is made that a storage device in a plurality of storage devices is experiencing a malfunction. The type of malfunction is determined. A SMART rebuilding technique, a normal building technique, a data migration technique, or a user data backup technique is selected to preserve the data in the storage device based on the determined type of the malfunction. The selected technique is performed on the storage device.

Abstract: A method for controlling a nonvolatile memory device includes reading a sub stripe including a plurality of sub pages stored in a first region, writing data stored in valid sub pages of the sub stripe to a second region different from the first region, and generating parity data using the data written to the second region and constituting a new sub stripe.

Abstract: A data grid node that is hosted by a computing system receives a request to prepare transaction operations for a multi-operational transaction for a commit. The transaction operations are associated with other data grid nodes in the data grid. The data grid node stores transaction state data for the multi-operational transaction in local memory associated with the data grid node and identifies other data grid nodes in the data grid that manage the data pertaining to the transaction operations for the multi-operational transaction. The data grid node sends the transaction state data to the other data grid nodes and the other data grid nodes store the transaction state data in local memory associated with the corresponding data grid node.

Abstract: A computer-readable medium storing a data management program makes a computer manage data redundantly stored in storage devices having storage areas split into slices for data management. The data management program realizes the following functions in the computer. A first function receives irregularity information indicating that each of one or more of the storage devices may be possibly faulty, and stores the irregularity information in a storage; and a second function determines, by reference to the irregularity information, whether or not a first storage device containing a slice to be accessed is possibly faulty, on receipt of access information indicating occurrence of a request to access the slice. When yes is determined, the second function instructs an external device to recover data stored in the slice, where the external device controls a second storage device storing redundant data identical to the data stored in the slice.

Abstract: An embedded memory with system repair data is provided. The embedded memory includes a flash memory unit, a storage unit, and a control unit. The flash memory unit stores an in-system programming (ISP) code. The storage unit stores a system repair code. The system repair code is used for rebuilding the ISP code. The control unit is electrically connected to the flash memory unit and the storage unit. The control unit determines whether the ISP code has been broken and reads the system repair code to rebuild the ISP code when the ISP code has been broken. A system repair method for the embedded memory is also provided, which comprises the steps of determining that the ISP code stored in the flash memory unit has been broken, reading the system repair code stored in the memory unit, and rebuilding the ISP code according to the system repair code.

Abstract: A method includes calculating redundancy information over a set of data items, and sending the data items for storage in a memory. The redundancy information is retained only until the data items are written successfully in the memory, and then discarded. The data items are recovered using the redundancy information upon a failure in writing the data items to the memory.

Abstract: A checkpointing fault tolerance network architecture enables a backup computer system to be remotely located from a primary computer system. An intermediary computer system is situated between the primary computer system and the backup computer system to manage the transmission of checkpoint information to the backup VM in an efficient manner. The intermediary computer system is networked to the primary VM through a first connection and is networked to the backup VM through a second connection. The intermediary computer system identifies updated data corresponding to memory pages that have been less frequently modified by the primary VM and transmits such updated data to the backup VM through the first connection. In such manner, the intermediary computer system holds back updated data corresponding to more frequently modified memory pages, since such memory pages may be more likely to be updated again in the future.

Abstract: Aspects of the subject matter described herein relate to querying and repairing data. In aspects, a component may detect that data on storage has become corrupted. In response, the component may request data from one or more redundant copies of the data and may determine which of the redundant copies, if any, are not corrupted. If a non-corrupted copy is found, the component may send a request that the corrupted data be repaired and may identify the non-corrupted copy to use to repair the corrupted data.

Abstract: A storage control apparatus manages a plurality of storage devices which belong to an RLU such that data is made redundant between different storage devices. If a first storage device fails, a rebuild controller executes a rebuild process to store the same data as recorded in the first storage device in a spare storage device. When the rebuild controller executing the rebuild process has failed in reading out data from a second storage device, a data recovery controller restarts the first storage device, and reads out data to be stored in the spare storage device from the restarted first storage device.

Abstract: A method, apparatus and system for data disaster tolerance are provided in embodiments of this disclosure, the method comprising: receiving node failure information from a node; detecting along a predecessor direction and a successor direction of a failure node indicated in the node failure information according to a pre-stored node sequence to determine a first effective predecessor node and a first effective successor node, and all failure nodes between the first effective predecessor node and the first effective successor node; instructing those of all effective nodes that have local content registration index stored on the failure nodes and the first effective successor node to perform a primary index recovery process, respectively, so as to recover primary indexes of all of the failure nodes into the primary index of the first effective successor node.

Abstract: The local storage performs remote copy to the remote storage. For low traffic failback remote copy, the remote storage performs a delta copy to the local storage, the delta being the difference between the remote storage and local storage. The local storage backs up snapshot data. The remote storage resolves the difference of the snapshot of the local storage and the remote storage. The difference resolution method can take one of several approaches. First, the system informs the timing of snapshot of the local storage to the remote storage and records the accessed area of the data. Second, the system informs the timing of snapshot of the local storage to the remote storage, and the remote storage makes a snapshot and compares the snapshot and remote copied data. Third, the system compares the local data and remote copy data with hashed data.

Abstract: A data management system (“DMS”) provides an automated, continuous, real-time, substantially no downtime data protection service to one or more data sources. A host driver embedded in an application server captures real-time data transactions, preferably in the form of an event journal. The driver functions to translate traditional file/database/block I/O and the like into a continuous, application-aware, output data stream. The host driver includes an event processor that can perform a recovery operation to an entire data source or a subset of the data source using former point-in-time data in the DMS. The recovery operation may have two phases. First, the structure of the host data in primary storage is recovered to the intended recovering point-in-time. Thereafter, the actual data itself is recovered. The event processor enables such data recovery in an on-demand manner, by allowing recovery to happen simultaneously while an application accesses and updates the recovering data.

Abstract: When a virtual tape of the main storage system is updated, journal data is created. The journal data is transmitted to the disaster recovery storage system asynchronously with the timing at which the write data is received. The journal data includes a marker to notify of the start of updating and a marker to notify of the completion of updating. The disaster recovery storage system prohibits the use of the copy destination data during the period from start of updating until completion of updating, and permits referencing the copy destination data during other periods.

Abstract: A checkpointing fault tolerance network architecture enables a backup computer system to be remotely located from a primary computer system. An intermediary computer system is situated between the primary computer system and the backup computer system to manage the transmission of checkpoint information to the backup VM in an efficient manner. The intermediary computer system is networked to the primary VM through a first connection and is networked to the backup VM through a second connection. The intermediary computer system identifies updated data corresponding to memory pages that have been least recently modified by the primary VM and transmits such updated data to the backup VM through the first connection. In such manner, the intermediary computer system holds back updated data corresponding to more recently modified memory pages, since such memory pages may be more likely to be updated again in the future.

Abstract: Integrating content into a storage system with substantially immediate access to that content. Providing high reliability and relatively easy operation with a storage system using redundant information for error correction. Having the storage system perform a “virtual write,” including substantially all steps associated with writing to the media to be integrated, except for the step of actually writing data to that media, including rewriting information relating to used disk blocks, and including rewriting any redundant information maintained by the storage system. Integrating the new physical media into the storage system, including accessing content already present on that media, free space already present on that media, and reading and writing that media. Recovering from errors during integration.

Abstract: An on-the-fly repair method for a memory includes: performing a block erase operation on the memory; checking whether the block erase operation is passed or not; finding whether there is any available and healthy redundancy block in the memory if the block erase operation is not passed; programming an address of a failed block to be repaired, an enable bit and at least one error correction bit into both first and second redundancy information regions in a redundancy information set of the memory; checking whether error in the first and the second redundancy information regions is recoverable based on the error correction bit; and if the error is recoverable, then programming the redundancy information set as effective to replace the failed block by the redundancy block related to the effective redundancy information set.

Abstract: Embodiments may recover from faults by forming a new set of rows by removing rows associated with faulting save operations and repeating the saving and forming operations using the new set of rows until a set of rows that can be saved from the known start state without fault is determined. When the subset of successful rows is found, embodiments are able to provide assurance that no side effects (i.e., code or operations triggered by saving of a data to a particular location) have been executed on behalf of any of the failed rows (side effects from custom PL/SOQL code included) by deferring execution of triggers until an entire set of rows can be saved and committed.

Abstract: A method and apparatus update an image stored in a memory of a device. A next block writing index n for updating a first target memory block of the memory is determined. Backup data is written to a backup block of the memory when n is an even number. The first target memory block is updated with the new data. The backup data is calculated based on a binary operation between new data corresponding to n and old data stored in a second target memory block corresponding to n+1, and the binary operation has reversibility. If n is the last block writing index, then the binary operation is not used and the backup data is the same as the new data.

Abstract: Disclosed is a method of calculating parity. The method dividing, by a client system, a file which is to be stored into chunks of a preset size and distributively storing the chunks in a plurality of data servers; sending, by the client system, a data write complete notification message to a metadata server; storing, by the metadata server, a file sent through the data write complete notification message in a recovery queue; and sending, by the metadata server, a random data server a parity calculation request for the file stored in the recovery queue.

Abstract: A system for disaster recovery including a controller (i) for controlling bandwidth usage of a disaster recovery system in accordance with a plurality of recovery point objectives (RPOs), each RPO designating a maximal time loss constraint for data recovery for an enterprise production system, and a corresponding bandwidth allocation for the disaster recovery system to use in replicating data for the enterprise production system, wherein the RPOs are applied in accordance with a calendar-based schedule of dates and times, and (ii) for issuing an RPO alert when the RPO maximal time loss constraint for a current date and time is not satisfied.

Abstract: A method and apparatus for networked recovery system is described herein. In one embodiment, a process is provided to obtain a type of recovery selected by a user. A non-volatile partition of a storage volume containing a recovery disk image is accessed. The recovery disk image does not include an installation package. If the obtained type of recovery is a predetermined type of recovery, a network connection is established using the recovery disk image and data is downloaded over the network connection for the obtained type of recovery. The obtained type of recovery of the system is performed.

Abstract: A storage controller having a plurality of storage devices and a control circuit providing a plurality of virtual volumes, to each of which a storage area in a plurality of pool volumes provided with the plurality of storage devices can be mapped for writing data in response to a write access sent from an information processing apparatus to a logical area in one of the plurality of virtual volumes, respectively. The control circuit, according to a search of the plurality of pool volumes for a certain storage area in which a certain data pattern is written, releases the certain storage area from mapping to a logical area in the plurality of virtual volumes, so that the control circuit can use the released certain storage area for mapping to a virtual volume of the plurality of virtual volumes as a destination of another write access from the information processing apparatus.

Abstract: A firmware recovery system includes a baseboard management controller (BMC) module, a south bridge, a basic input and output system (BIOS) module, a multiplexer and a storage module. The BIOS module is connected to the BMC module by the south bridge and determines whether a firmware file of the BMC module is corrupt. The multiplexer selectively connects the BIOS module or the BMC module to the south bridge. The storage module stores a new firmware file. When the firmware file of the BMC module is corrupt, the BIOS module controls the multiplexer to select the BMC module to connect to the south bridge. The BIOS module reads the new firmware file from the storage module to recover the corrupt firmware file from the BMC module.

Abstract: Distributed data, having been stored in a distributed storage system as a collection of distributed data elements, is recovered based on connection of multiple user nodes, each user node having stored selected distributed data elements as a corresponding portion of the distributed data during replication of the distributed data elements throughout the distributed storage system. Each distributed data element is identifiable by a corresponding unique object identifier (OID). Each user node includes a discovery resource for discovering reachable user nodes, a local cache configured for identifying at least the corresponding portion of the distributed data based on the respective OIDs, and an identification service module configured for resolving a data object to a corresponding OID, via the corresponding local cache, or based on sending a query to the reachable user nodes. Hence, user nodes can recover distributed data based on exchanging resolution information and OID information.

Abstract: A method and system of recovering a system that has experienced a fault includes a backup device to enable access of a network through the interface in response to the fault. The system includes a main operational portion that controls operation of the system under normal conditions. However, if a fault occurs, then the backup device can be selected to take over control of the system so that data can be retrieved from a backup storage to recover the system. The backup device includes software and/or hardware components to enable the system to access a network even though the main operational portion may not be functioning properly.

Abstract: An information system including: a first and second storage apparatus including a first and second volume; a failure detection storage apparatus including a third volume; wherein, for backup purposes, the first and second volumes form a remote copy pair, and, for I/O request purposes, are recognized as a single volume labeled with a same volume identifier, but accessible by alternative access paths designated with differing priorities; wherein, if one apparatus detects a failure in the other or a connection failure, the apparatus detecting the failure stores, in the third volume, a failure information flag showing failure; wherein, upon receiving the I/O request through the second access path, the second storage apparatus determines whether the failure information flag is stored in the third volume, and sends an error reply of the I/O request to the host computer if the failure information flag is stored in the third volume.

Abstract: Data replication in a distributed node system including one or more nodes. A consensus protocol for failure recovery is implemented. Data items and information relating to consensus protocol roles of participant nodes are stored in at least some of the plurality of nodes. Logical logs stored in at least some of the plurality of nodes are created. The logical logs contain additional consensus protocol information including container metadata and replicated data.

Abstract: Transactional memory implementations may be extended to include special transaction communicator objects through which concurrent transactions can communicate. Changes by a first transaction to a communicator may be visible to concurrent transactions before the first transaction commits. Although isolation of transactions may be compromised by such communication, the effects of this compromise may be limited by tracking dependencies among transactions, and preventing any transaction from committing unless every transaction whose changes it has observed also commits. For example, mutually dependent or cyclically dependent transactions may commit or abort together. Transactions that do not communicate with each other may remain isolated. The system may provide a communicator-isolating transaction that ensures isolation even for accesses to communicators, which may be implemented using nesting transactions. True (e.g., read-after-write) dependencies, ordering (e.g.

Abstract: Embodiments of the invention relate to selecting a data restore point with an optimal recovery time and recovery point. An exemplary embodiment includes generating a problem search criterion for an entity with corrupted data. Dependencies relied on by the entity to function are determined. At least one event signature match is found that comprises information for an event being logged in a event log, and is associated with the dependencies. At least one data restore point created prior to an occurrence of a particular event in the at least one event signature match is selected. The particular event having caused the data to be corrupted. The at least one data restore point is selected to restore data to a storage system with the corrupted data.

Abstract: The invention provides a method for data recovery. In one embodiment, a memory comprises a plurality of pages for data storage. First, first data is obtained from a host. A first page for storing the first data is then selected from the pages of the memory. A start page link indicating the first page is then stored in the memory. The first data, a first page link indicating a next page, and first FTL fragment data corresponding to the first page are then written into the first page. Next data is then obtained from the host. The next data, a next page link indicating a subsequent page, and FTL fragment data corresponding to the next page are written into the next page.

Abstract: Provided is a RAID controlled storage device of a PCI-Express (PCI-e) type, which provides data storage/reading services through a PCI-Express interface. The RAID controller typically includes a disk mount coupled to a set of PCI-Express SSD memory disk units, the set of PCI-Express SSD memory disk units comprising a set of volatile semiconductor memories; a disk monitoring unit coupled to the disk mount for monitoring the set of PCI-Express memory disk units; a disk plug and play controller coupled to the disk monitoring unit and the disk mount for controlling the disk mount; a high speed host interface coupled to the disk monitoring unit and the disk mount for providing high-speed host interface capabilities; a disk controller coupled to the high speed host interface and the disk monitoring unit; and a host interface coupled to the disk controller.

Abstract: In one embodiment, a method of storing data includes storing a first copy of data in a solid state memory and storing a second copy of the data in a hard disk drive memory substantially simultaneously with the storing the first copy. In another embodiment, a system for storing data includes a solid state memory, at least one hard disk drive memory, and a controller for controlling storage of data in the solid state memory and the hard disk drive memory. Other methods, systems, and computer program products are also described according to various embodiments.

Abstract: An apparatus comprising a logically contiguous group of at least two drives, a loop and a compression/decompression circuit. Each of the drives comprises (i) a first region configured to store compressed data of a previous drive and (ii) a second region configured to store uncompressed data of the drive. The loop may be connected to the next drive in the logically contiguous group. The compression/decompression circuit may be configured to compress and decompress the data stored on each of the drives.

Abstract: An apparatus comprising a logically contiguous group of at least three drives, a first loop, a second loop, and a compression/decompression circuit. Each of the drives comprises (i) a first region configured to store compressed data of a previous drive, (ii) a second region configured to store uncompressed data of the drive, (iii) a third region configured to store compressed data of a next drive. The first loop may be connected to the next drive in the logically contiguous group. The second loop may be connected to the previous drive of the logically contiguous group. The compression/decompression circuit may be configured to compress and decompress the data stored on each of the drives.

Abstract: The storage system is coupled to a computer and includes a plurality of physical storages being used to configure a first logical storage and a second logical storage, a control unit receiving a read request and a write request from the computer; and a cache memory storing data which is sent to the computer. The control unit determines whether a request from the computer is a write request or a read request. If it is a read request, the control unit reads data from the cache memory or at least one of the plurality of physical storages based on the read request. If it is a write request, the control unit determines whether destination of the write request is the first logical storage.

Abstract: Data storage reliability is maintained in a write-back distributed data storage system including multiple nodes, each node comprising a processor and an array of failure independent data storage devices. Information is stored as a set of stripes, each stripe including a collection of multiple data strips and associated parity strips, the stripes distributed across multiple corresponding primary data nodes and multiple corresponding parity nodes. A primary data node maintains the data strip holding a first copy of data, and each parity node maintains a parity strip holding a parity for the multiple data strips. A read-modify-write parity update protocol is performed for maintaining parity coherency, the primary data node driving parity coherency with its corresponding parity nodes, independently of other data nodes, in order to keep its relevant parity strips coherent.

Abstract: Data storage reliability is maintained in a write-back distributed data storage system including multiple nodes. Each node comprises a processor and an array of failure independent data storage devices. Information is stored as a set of stripes, each stripe including a collection of at least a data strip and associated parity strips, the stripes distributed across a primary data node and multiple corresponding parity nodes. A read-other parity update protocol maintains parity coherency. The primary data node for each data strip drives parity coherency with the corresponding parity nodes, independently of other data nodes, in keeping relevant parity strips for the primary data node coherent. A parity value is determined based on data other than a difference between new data and existing data. A new parity value is based on new data and dependent data, wherein with respect to one data value, dependent data comprises other data encoded in a corresponding parity value.

Abstract: Disclosed are a storage control apparatus, a storage control program, and a storage control method that collect the backup of storage data in units of generation at low cost. A storage control apparatus that creates a generation backup of a storage, comprising: a first copy section that creates a snapshot of at least one of all data stored in the storage at an indicated time point and difference data stored in the storage in an indicated time period; a second copy section that creates a mirror of at least one of all data stored in the storage and difference data stored in the storage in an indicated time period; and a controller that causes one of the first and second copy sections to copy all data stored in the storage and causes the other to copy difference data between generations stored in the storage.

Abstract: In a virtual disk library device access of data stored in a tape can be conducted at a high speed with a high-speed archiving process from a disk to the tape in units of LUs maintained. The efficiency of update of the data stored in the tape can be improved. In this system, when the data stored in the tape is to be accessed with a high-speed archiving process in units of LUs from the disk to the tape maintained, a disk staging process is performed in the unit of a page that is smaller than the unit of an LU, and accordingly, high-speed access can be implemented. In addition, when an update process for the data (LU) stored in the tape is performed, the host can be responded by only staging an update target page of the LU, and a prior disk staging process is performed for the remaining pages of the LU in the background. Accordingly, when the data is re-stored in the tape, immediately storing the data in the tape can be performed without performing a staging process.

Abstract: A method for processing data using snapshots is provided. The method comprises generating a primary snapshot of data stored in a first storage medium, wherein the primary snapshot is a copy of the data stored in the first storage medium at a point in time; generating one or more secondary snapshots of the primary snapshot, wherein the secondary snapshots are copies of the data stored on the first storage medium at the point in time; and extracting the data stored in the first storage medium at the point in time by accessing the data included in the secondary snapshots, wherein multiple processing units concurrently transform the extracted data and load the transformed data onto a second storage medium.

Abstract: Replicated instances in a database environment provide for automatic failover and recovery. A monitoring component can periodically communicate with a primary and a secondary replica for an instance, with each capable of residing in a separate data zone or geographic location to provide a level of reliability and availability. A database running on the primary instance can have information synchronously replicated to the secondary replica at a block level, such that the primary and secondary replicas are in sync. In the event that the monitoring component is not able to communicate with one of the replicas, the monitoring component can attempt to determine whether those replicas can communicate with each other, as well as whether the replicas have the same data generation version. Depending on the state information, the monitoring component can automatically perform a recovery operation, such as to failover to the secondary replica or perform secondary replica recovery.

Abstract: A system comprises at least two random access memory (RAM) elements arranged to store data redundantly. The system further comprises RAM routing logic comprising comparison logic operably coupled to the at least two RAM elements and arranged to compare redundant data read from the at least two RAM elements, and check and validation logic, independent of the RAM routing logic, operably coupled to the at least two RAM elements and arranged to additionally detect an error in the redundant data read from the at least two RAM elements and provide an error indication signal to the RAM routing logic in response thereto. The RAM routing logic further comprises selection logic arranged to dynamically select redundant data from one of the at least two RAM elements based on the comparison of the redundant data and the error indication signal.

Abstract: A management system, which manages a host computer and a storage system, holds cluster information, specifies an active-state host computer and an inactive-state host computer based on a backup instruction specifying a virtual host identifier, determines the need for executing a replication for disaster recovery use, and when necessary, executes this replication for disaster recovery use in combination with a replication for backup use.

Abstract: According to one embodiment, a data storage apparatus includes a RAID controller, error detectors, and memory units. The RAID controller receives an encoded data stream, divides the encoded data stream into a predetermined number of data blocks and generates a block of parity data. The data blocks and the parity data block are distributed to the error detectors. The error detectors add an error detection code to the data blocks and the parity data block, respectively. The memory units receive the data blocks and the parity data block from the error detectors and set the data blocks and the parity data block to have the writable page units, respectively. Each of the memory units includes a plurality of memory chips and a memory controller. The memory controllers write the data blocks and the parity data block of the writable page units in the memory chips.

Abstract: A method is disclosed for recovering data associated with a damaged file stored in a NAND gate array memory. The method includes the steps of: identifying all meta data associated with the damaged file; identifying each logical block address of all identified meta data; collecting all physical block addresses associated with one of the identified logical block addresses or the identified meta data; counting in a replace table (ReplTable) a number of matches to a physical block address of the damaged file for each physical block address of the damaged file; choosing a block in a linked list that corresponds to the physical block address of the block in the linked list; and linking all chosen blocks to form a replicated file.