Abstract: An aspect includes determining, in response to an efficiency indicator associated with a destination disk array of a plurality of destination disk arrays, to relocate at least a portion of data currently on a source Logical Unit (LUN) of a source disk array of a plurality of source disk arrays to the destination disk array. The efficiency indicator represents an amount of data on the source LUN that also resides on the destination disk array. The destination disk array supports deduplication. An aspect also includes evaluating multiple destination LUNs of the destination disk array to relocate the data to based on the efficiency indicator and at least one capacity-based factor corresponding to the multiple destination LUNs, selecting one of the multiple destination LUNs to relocate the data based on results of the evaluating, and relocating the data from the source LUN to the selected one of the multiple destination LUNs.

Abstract: Transferring data from a storage device to cloud service includes initiating a snapshot of the data, accessing each block of the data corresponding to the snapshot to transfer each block to the cloud service, and terminating the snapshot after all of the blocks have been transferred to the cloud service. At least some blocks of the storage device that are modified after initiating the snapshot may be copied from the storage device to a storage pool prior to modification. Only a first modification of a particular one of the blocks of the storage device may cause the particular one of the blocks to be copied to the storage pool. Accessing each block of the data may include accessing blocks of the storage pool. Modifying a particular one of the blocks of the storage device may include modifying a corresponding block of a storage pool.

Abstract: Techniques are provided for persistent hole reservation. For example, hole reservation flags of operations targeting a first storage object of a first node are replicated into replication operations targeting a second storage object of a second node during a transition operation to transition the first storage object and the second storage object from an asynchronous replication state to a synchronous replication state. In another example, the second storage object is grown to a size of a replication punch hole operation that failed due to targeting a file block number greater than an end of size of the second storage object.

Abstract: Systems and methods for backing up and restoring virtual machines in a cluster environment. An instrumentation interface enables configuration data to be stored with save sets during backup and enables the configuration of the destination to be adjusted based on the stored configuration during a restore.

Abstract: One or more techniques and/or systems are provided for controlling restoration of a storage aggregate. For example, a local storage device, located at a first storage site, and a remote storage device, located at a second storage site, may be assigned to a first storage aggregate. Responsive to a disaster of the first storage site, a gate may be created for the local storage device. The gate may block automated reconstruction and/or automated synchronization that may otherwise occur with respect to the local storage device. Until the local storage device is restored, the remote storage device may be used to service I/O requests that were otherwise directed to the local storage device. Responsive to receiving a user restoration command, the gate may be removed from the local storage device. Synchronization between the local storage device and the remote storage device may then be facilitated.

Abstract: A primary write request that is to modify a primary portion of primary data stored in a primary storage node is received. The primary write request is to be replicated to create a current secondary write request. The current secondary write request is to modify a current secondary portion of secondary data that is stored in a secondary storage node. A current data range of the current secondary portion is determined. A determination is made of whether a previous secondary write request is in process of modifying a previous data range that at least partially overlaps with a current data range of the current secondary portion. Execution of the primary write request is suspended, until the previous secondary write request has completed updating the secondary storage node.

Abstract: Example embodiments of the present invention relate to methods, systems, and a computer program product for managing a virtual datacenter. The method includes tracking configuration metadata for a virtual datacenter operating at a first site and simulating the virtual datacenter at a second site according to the tracked virtual datacenter configuration metadata. An analysis then may be performed on operation of the simulated virtual datacenter at the second site.

Abstract: Techniques for data synchronization involve obtaining a first bitmap about a first storage device, the first storage device including a group of storage areas, a bit in the first bitmap indicating whether data in a corresponding storage area of a first size in the group of storage areas is to be synchronized to a second storage device. The technique further involves, in response to a configuration of the first storage device being changed, determining a second size of a storage area in the group of storage areas. The technique further involves converting the first bitmap into a second bitmap based on the first size and the second size. In addition, the technique further involves synchronizing data from the first storage device to the second storage device based on the second size and the second bitmap.

Abstract: A storage system in one embodiment comprises a plurality of storage devices and an associated storage controller. The storage controller implements a logical storage layer in which logical blocks are associated with respective content-based signatures and a physical storage layer in which the content-based signatures are associated with respective physical blocks in the storage devices. The storage controller maintains reference counts for respective ones of the physical blocks, with a given such reference count indicating a number of the logical blocks that map via their respective content-based signatures to the same physical block, groups the content-based signatures into one or more subsets, and for a given one of the subsets, executes a scan of the logical blocks to detect any discrepancies in the maintained reference counts for the given subset, and corrects detected discrepancies by updating the reference counts for the given subset based at least in part on results of the scan.

Abstract: Various examples are directed to systems and methods for programming memory. A programming appliance may receive a command file comprising a first pre-generated digital signature. The first pre-generated digital signature may be associated with a memory system, with a first command and with a first memory system counter value. The programming appliance may send to a memory system a first command message. The first command system may comprise the first command and the first pre-generated digital signature.

Abstract: Systems and methods for creating virtual machine snapshots. An example method comprises: receiving a request to create a snapshot of a virtual machine running on a host computer system; protecting from modification a plurality of virtual memory pages of the virtual machine; responsive to detecting an attempt to modify a virtual memory page of the plurality of memory pages, copying the virtual memory page to a queue residing in a random access memory (RAM) of the host computer system; making the virtual memory page writable; retrieving the virtual memory page from the queue; writing the virtual memory page to a disk of the host computer system; and responsive to exhausting the queue, completing creation of the snapshot of the virtual machine.

Abstract: An apparatus in an illustrative embodiment comprises at least one processing device comprising a processor coupled to a memory. The processing device detects a drive failure in a first storage system comprising a plurality of drives configured in accordance with a designated redundant array of independent disks (RAID) arrangement, identifies a plurality of data pages to be rebuilt in order to recover from the drive failure, retrieves hash digests of respective ones of the identified data pages, and utilizes the hash digests to request respective corresponding data pages from a second storage system. For each of one or more data pages returned by the second storage system, the processing device utilizes the returned data page as a rebuilt data page in recovering from the drive failure so as to avoid reading multiple data pages from remaining ones of the drives of the designated RAID arrangement to rebuild that data page.

Abstract: Protecting sensitive information in connection with a trace of an original execution of an entity. Embodiments include identifying that original information—which was accessed based on an original execution of one or more original executable instructions of the entity—comprises sensitive information. Based on the original information comprising the sensitive information, embodiments include performing one or both of (i) storing first trace data comprising alternative information—rather than the original information, while ensuring that an execution path that was taken by the entity based on the original information is also taken during replay of the original execution of the entity; or (ii) storing second trace data that causes zero or more alternative executable instructions—rather than the one or more original executable instructions of the entity—to be executed during the replay of the original execution of the entity.

Abstract: According to one embodiment, a storage system includes a first storage device and a second storage device. In a case where the first storage device performs writing or updating of data on a first primary volume, the first storage device transmits the data to a second storage device based on a first replication pair. In a case where the first storage device creates or updates a second primary volume that is a snapshot of the first primary volume, the second storage device creates or updates a second secondary volume that is a snapshot of the first secondary volume configuring the first replication pair with the first primary volume.

Abstract: A request associated with restoring a previous version of a linked clone virtual machine is received. One or more changes between a base image of a parent virtual machine and the previous version of the linked clone virtual machine are determined. One or more data blocks corresponding to the base image and one or more data blocks corresponding to the determined changes are provided to a remote system.

Abstract: A server rack may include a chassis management controller (CMC), a server having a baseboard management controller (BMC) configured to communicate with the CMC, a controller stored in the server rack for interoperating with a cache memory, and a set of solid state devices (SSDs) providing data storage. The CMC may amalgamate data storage provided by the SSDs and partition the amalgamated data storage into an individual logical cache for use with or by the BMC or controller.

Abstract: Enabling a distributed data processing system to process a data set from local storage devices by dynamically reallocating portions of the data set.

Abstract: A data backup method for backing up target data, through a driver module, from a first storage device to a second storage device is disclosed. The first storage device includes a first storage unit that stores the target data, and a first control unit that accesses the first storage unit based on a first logical-to-physical mapping table. The second storage device includes a second storage unit and a second control unit that accesses the second storage unit based on a second logical-to-physical mapping table. The method includes steps of: reading the target data from the first storage unit without accessing the first logical-to-physical mapping table and transmitting the target data to the driver module; transmitting the target data to the second control unit; and writing the target data to the second storage unit without accessing the second logical-to-physical mapping table.

Abstract: Systems and method for determining a storage location according to legal requirements. According to one example a dispersed storage (DS) processing unit receives data to store in a dispersed storage network (DSN) and assesses attributes of data to produce a determination of whether the data falls into one or more defined legal categories. The DS processing unit also determines one or more attributes of a storage location in the DSN. The DS processing unit then determines whether or not to select the storage location based on the determination and based on one or more attributes of the storage location. If storing data of the identified category would be illegal the DS processing unit evaluates the another storage location, and so on. If no available storage location is found the DS processing unit returns an error indicating that no legal storage location is found.

Abstract: Examples of techniques for controlling write requests to a memory structure having limited write ports are described herein. An aspect includes storing, in a first queue, write requests received from a first source having a first priority. Another aspect includes storing, in a second queue, write requests received from a second source having a second priority, wherein the second priority is lower than the first priority. Aspects also include identifying a selected queue from the first queue and the second queue based on a selection algorithm, which is a function of a state associated with the first queue and the second queue. Aspects further include forwarding a write request from the selected queue to a write port of the memory structure.

Abstract: An apparatus in one embodiment comprises a first host device comprising a processor coupled to a memory. The first host device is configured to assign to additional host devices different portions of a source logical unit designated for migration to a target logical unit. In conjunction with migration of the assigned portions of the source logical unit to the target logical unit by the additional host devices, the first host device is configured to receive from the additional host devices respective sets of information each characterizing one or more writes directed to the corresponding assigned portion during the migration. The first host device is further configured to update the target logical unit based at least in part on the received sets of information. In some embodiments, the first host device is configured to assign to itself a portion of the source logical unit designated for migration to the target logical unit.

Abstract: One embodiment is related to a method for applying deduplication and/or compression to data stored or to be stored at a non-volatile memory (NVM) cache comprising: identifying the NVM cache; determining whether deduplication or compression, or both, is to be applied to data stored or to be stored at the NVM cache; and applying either deduplication or compression, or both, to the data stored or to be stored at the NVM cache.

Abstract: Aspects of the present disclosure relate to synchronizing data writes. An update to a file stored on a virtual tape image is received. A position and length of the file is recorded as an invalid data area. The virtual tape image is then synchronized with a tape. The invalid data area is then released from the virtual tape image.

Abstract: A new snapshot of a storage volume is created by suppressing write requests. Once pending write requests from the computing nodes are completed, storage nodes create a new snapshot for the storage volume by allocating a new segment to the new snapshot. Subsequent write requests to the storage volume are then performed on the segments allocated to the new snapshot. An orchestration layer implements a bundled application that is provisioned with storage volumes and containers. A snapshot of the application may be created and used to rollback or clone the application. The amount of processing cores, memory, and containers may be increased or decreased based on usage. Amount of storage allocated to a storage volume may be augmented by a snapshot reservation ratio. The snapshot reservation ratio is adjusted over time according to usage.

Abstract: Provided is a method, system, and computer program product for managing tasks in a computing system using a virtual node. A processor may register a virtual node for handling tasks allocated by a scheduling node in a computing system, the computing system comprising the scheduling node and a group of actual computing nodes processing tasks allocated by the scheduling node, and the scheduling node takes the virtual node as an actual computing node. A performance level of the computing system is obtained. Capacity of the virtual node is set based on the obtained performance level, such that the scheduling node allocates tasks to the virtual node based on the capacity of the virtual node. In response to at least one task being allocated by the scheduling node to the virtual node, the at least one task is received by the virtual node.

Abstract: A system for improving workload performance using data locality and workload placement may include a schedule module that schedules workloads for execution on a computing device in one or more computing devices. Also, the computing devices access a shared data storage. Further, the system may include a tracking module that maintains a data store that associates paths in the shared data storage with dispatched workloads and associates the paths with at least one computing device, wherein a dispatched workload and the at least one computing device accessed a path; and a preferred device identification module that identifies preferred computing devices in the one or more computing devices for executing undispatched workloads based on information in the data store, wherein the schedule module schedules the execution of the undispatched workloads in response to the identified preferred computing devices.

Abstract: Systems and methods described herein generally relate to storing and verifying data. In some embodiments, reference levels are generated according to time intervals, where the first reference level comprises a predetermined number of the time intervals, and where each of the time intervals of the remaining reference levels is comprised of a predetermined number of the time intervals of a previous reference level. Hashes of data can be created at the first reference level by performing a hashing function on the data in a time-sequenced manner. First reference level time interval hashes may be generated by performing the hashing function on the hashes of the data at each of the time intervals of the first reference level. Hashes for remaining reference level time intervals can be generated by performing the hashing function on the hashes of each of the time intervals of the previous reference level.

Abstract: Provided in the embodiments of the disclosure are methods for transmitting data, a terminal device and a network device. One method includes: a terminal device receives semi-static configuration information sent by a network device, the semi-static configuration information being used for indicating an initial state of a duplicated-data transmission function of a Packet Data Convergence Protocol (PDCP) entity corresponding to a Radio Bearer (RB), and the initial state including an activated state or a deactivated state; and the terminal device establishes a first RB according to the semi-static configuration information. The methods, the terminal device and the network device provided by the embodiments of the disclosure help to improve the reliability of data transmission.

Abstract: A storage appliance arranges snapshot data and snapshot metadata into different structures, and arranges the snapshot metadata to facilitate efficient snapshot manipulation, which may be for snapshot management or snapshot restore. The storage appliance receives snapshots according to a forever incremental configuration and arranges snapshot metadata into different types of records. The storage appliance stores these records in key-value stores maintained for each defined data collection (e.g., volume). The storage appliance arranges the snapshot metadata into records for inode information, records for directory information, and records that map source descriptors of data blocks to snapshot file descriptors. The storage appliance uses a locally generated snapshot identifier as a key prefix for the records to conform to a sort constrain of the key-value store, which allows the efficiency of the key-value store to be leveraged.

Abstract: Disclosed subject matter relates to data backup operations including a method of automating data backup in Hybrid Cloud and Data Centre (DC) environment. A backup automation system receives a latest backup report including data of workloads associated with clients and detects missing workloads in the latest backup report by comparing the latest backup report with a master inventory report. Furthermore, the backup automation system identifies one or more parameters corresponding to the missing workloads and performs data backup operations for the missing workloads based on the one or more parameters. Further, the backup automation system updates timestamp for each of the missing workloads upon completion of the data backup operations for automating the data backup. The present disclosure ensures successful backup of each and every workload, in accordance with the SLA, by automatically performing the data backup operations, and also allows integrating data backup operations across customer preferred platforms.

Abstract: The present disclosure provides a method, apparatus, and computer program product for generating consistent snapshots without quiescing applications. The snapshots correspond to consistency groups that in turn correspond to one or more vDisks on one or more nodes. Some embodiments of the present disclosure address the problem of generating consistent backup snapshots that cover cases of multiple virtual machines (VMs) that operate in a multi-node distributed computing environment (e.g., in clusters) without quiescing the accessing entity(ies). In some embodiments, the process includes identification of a triggering snapshot event, disabling of write complete responses to requesting entities for the resources corresponding to the snapshot to be generated, generating snapshots while one or more additional write requests are received, and using one or more techniques to insure that all actions corresponding to the snapshotting function do not occur outside of a specified time frame.

Abstract: A self-correcting memory device (SCMD) includes a non-destructive memory array that includes memory cells arranged in rows and columns that includes a storage section, a comparison section, a comparing element, a selective write unit and a row decoder. The storage section stores a first copy, a second copy and a third copy of a data item in physically separated columns. The comparison section temporarily stores the first copy in a first row and the second copy in a second row. The comparing element compares between bits of the first and second rows and provides at least one per bit change indication. The selective write unit receives at least one per bit change indication and fetches from the third copy a correct value for each bit having a positive bit change indication. The row decoder concurrently writes each correct value back to its bit location in the first and second copies.

Abstract: Some examples include performing a priority synchronization of a computing device to download a selected set of data files to the computing device from a distributed backup system. Data files are downloaded to a computing device by synchronizing with a server of the distributed backup system. A priority sync downloads a subset of the data files as priority files, rather than all of the data files of the user, thereby minimizing the computing resources consumed to download the data files. The priority sync can select the priority files based on various criteria, including an access pattern of the data files, attributes of the data files, or attributes of the computing device. The priority sync may also download non-priority files. The priority files may be downloaded in their original format and the non-priority files may be downloaded in a downgraded format.

Abstract: A module for rewriting application code as a failure-atomic transaction is disclosed. An application delineates a code fragment that is to become a failure-atomic transaction by writing a tx_begin( ) and tx_end( ) functions into its code. A module detects the tx_begin( ) and tx_end( ) functions and rewrites the code fragment as a failure-atomic transaction. The rewritten code is then available to be executed by the application. The rewritten code stores values and locations of stores to persistent memory locations so that the transaction can be either undone or redone in the case of an application error or a power failure. If the transaction is an undo type of transaction, the application can be rolled back to a state prior to the failure. If the transaction is a redo type of transaction, the application can be advanced to a correct state after the error.

Abstract: A system and method of dynamic backup policy generation based upon a user's behavior is provided. The method may include detecting a user's usage pattern of files within a computing system based upon the user's backup or restore activities. In some embodiments, the backup system may identify the files that have been modified and calculate the percentage of modification away from a predetermined baseline or another previously stored version. The system may generate a list of the identified files along with these percentages to form the user's usage pattern. The method may further include generating a user's profile including files having high access rates in accordance with this usage pattern and adjusting a backup policy based upon the user's profile such that these files are backed-up more frequently. The backup policy may also be adjusted based upon a detected level of risk associated with the user.

Abstract: Disclosed are a method and system for cloud storage of a video, and method and system for previewing a cloud-stored video. The method for the cloud storage of the video includes: after receiving a video recording plan issued by a platform, a management server determines a target storage device according to a load balancing policy, and issues the video recording plan to the target storage device; the target storage device obtains and stores, according to the video recording plan, a video stream from a front-end device corresponding to the video recording plan; when the target storage device is not able to obtain the video stream from the front-end device, the target storage device sends an alarm to the management server; and after receiving the alarm, the management server issues the video recording plan to other storage devices according to the load balancing policy.

Abstract: A first storage node configured to store data associated with a user is allocated. The data stored on the first storage node is mirrored at a second storage node. A resiliency mechanism is implemented at the first and second storage nodes. The resiliency mechanism is configured to restore data on at least one of the storage devices of the first and second storage nodes. In response to a loss of availability of either the first or second storage node and a loss of availability of one or more storage device on an available storage node, data on the unavailable storage devices of the available storage node is recovered using the resiliency mechanism of the available storage node.

Abstract: The present invention relates to a method and an apparatus for controlling, by a client, a server via Bluetooth. The present invention provides a method and an apparatus that form a Bluetooth low energy (LE) connection with a server: transmit, to the server, a first write request message requesting writing of a control point characteristic for an instruction of a specific operation; receive a first write response message in response to the write request message; and receive, from the server, a first instruction message for instructing whether to perform the specific operation, wherein the first write request message includes a first operation code indicating the specific operation and a first effective time indicating a time of performing the specific operation.

Abstract: The system, products, and methods disclosed herein relate to an improved configuration for geographically dispersed data restart (“GDDR”) systems. Specifically, the teachings herein ensure a particular GDDR instance does not react to messages issued from address spaces outside of its affinity group. We use the term message “affinity group” to mean the combination of a particular GDDR instance and its set of Mainframe Enablers started tasks. By ensuring that the particular GDDR instance does not react to messages intended for recipients outside of its affinity group, we improve computer functionality and efficiency by facilitating further partitioning of the logical partition. Once the logical partition is further partitioned into additional address spaces, it is possible to run Mainframe Enablers and/or additional GDDR instances independent of the particular GDDR instance of concern.

Abstract: Disclosed herein are methods, systems, and processes to perform backup operations using replicas. A replica of a virtual machine is created as part of a replication operation. The replica includes data associated with the virtual machine and metadata associated with applications executing on the virtual machine. A backup operation generates a backup image from the replica using the metadata.

Abstract: A system and technique for creating, in a non-native format, verified snapshots and change log archives for data in a database (e.g., tables, partitions, etc.). To verify accuracy of a conversion of the data and corresponding change log data from a native format to a non-native format, both data from the database and the corresponding change logs are processed separately with a forward transformation process, and then a reverse transformation process. The results of the reverse transformations are then compared to the original data to catch data corruptions or errors when performing the format conversion and creating the snapshot or change log archive so that the corruption or error is not propagated to the snapshot/archive. Various forms of error detection (e.g., byte-level, raw data comparisons, checksums, etc.) and error handling are disclosed. The verified snapshots and change log archives may be used to restore the database, for example.

Abstract: Example implementations relate to buffer-based update of state data. In example embodiments, a computing device may obtain current state data from a first buffer and determine next state data based at least on the current state data. The computing device may also obtain last difference data that corresponds, for example to current state data that is different from previous state data. The last difference data may be obtained, for example, using a difference data identifier. The computing device may store the last difference data in the second memory buffer. The computing device may also store in the second memory buffer new difference data corresponding to differences between the next state data and the current state data. The computing device may also update the difference data identifier based on the new difference data.

Abstract: Technologies for adjusting the performance of data storage devices based on telemetry data include a compute device with a compute engine. The compute engine is configured to receive, with communication circuitry and through a network, telemetry data indicative of a present configuration and performance of each of multiple data storage devices, determine, as a function of the received telemetry data, a replacement configuration to improve the performance of one or more of the data storage devices, and send, with the communication circuitry, responsive data that is usable by the one or more of the data storage devices to improve the performance of the one or more data storage devices.

Abstract: Disclosed are systems and methods for proactive disaster recovery. The described technique monitors for events raised by a system of interconnected external sensors and other devices for obtaining data on the external environment of servers. The system uses these events as a chain of triggers according to which preventative or preparatory actions for disaster recovery are performed.

Abstract: A “Local Ingestion” (LI) Server resides and operates in the LAN of a business organization, and provides backup storage for data generated using various software applications locally installed on client terminals (“non-SaaS data”) and data generated using various SaaS applications accessed by client terminals via the Internet (“SaaS data”). The LI Server can receive data generated in a native format by either a local non-SaaS application or one or more SaaS applications and convert from different native data formats to an application platform-independent or “canonical” format for backed-up SaaS data and non-SaaS data. The LI Server may then analyze data generated using different source applications, and backed-up in a canonical format, so as to identify particular content, patterns, relationships, and/or trends and thereby extract valuable business-related or other information from multiple cross-platform files.

Abstract: Systems and methods for providing visibility in application transactions between users and an application. In some embodiments, an application security microscope is deployed at network locations to capture and analyze application transaction data and to identify API call data. The application security microscope includes an API classifier to classify captured API call data. The API classifier generates API specifications which are then used to aid in the capture and identification of API call data in the application transaction data, thereby improving the capture efficiency and accuracy of policy actions.

Abstract: A non-transitory computer-readable storage medium storing a program that causes a computer to execute a process, the process includes calculating, when a request for a processing for a plurality of apparatuses is received, an estimated processing time period that is an estimated value of a time period taken to perform the processing based on a processing time period in a past execution history of the processing; referring to a time schedule that records a schedule of processing including replication for each of the plurality of apparatuses; and selecting one of the plurality of apparatuses as a target apparatus for performing the requested processing based on a sum total of overlapping times between the calculated estimated processing time period and the recorded schedule.

Abstract: A management device includes a processor that determines, upon receiving a request for deletion of a first volume set in a first storage area of a first storage device, whether a second volume different from the first volume is set in the first storage area. The processor detects, when it is determined that the second volume is set, a continuous empty area equal to or larger than the second volume from among storage areas of a second storage device. The processor causes the first storage device to perform the deletion of the first volume from the first storage area, evacuation of data of the second volume to the continuous empty area, and upon completion of the evacuation, migration of the second volume to a migration destination area within the first storage area from the second storage device.

Abstract: A method for processing files as a preemptive measure against a ransomware activity. The method comprises scanning a plurality of file operation requests sent to an operating system (OS) executed on a computing device to detect a guarded file operation request that comprises instructions to process a file managed by a file system used by said OS, delaying an execution of said guarded file operation request, temporarily storing a copy of said file in a backup storage in response to said detection of said guarded file operation request, and stop delaying said execution of said guarded file operation request when said copy is stored in said backup storage.

Abstract: A storing method is provided. The storing method includes: receiving a driving instruction by a host, wherein the driving instruction triggers a driver to collect a user information, and the driver generates a hit rate information according to the user information and generates a mapping table according to the hit rate information; receiving the mapping table from the driver by a processing unit of a storage device, wherein the storage device does not have any dynamic random access memory (DRAM); storing the mapping table in a static random access memory (SRAM); storing a plurality of storing data in a number of NAND flash memories, wherein when the host receives an accessing instruction, the processing unit reads the mapping table in the SRAM to find the storing data corresponding to the accessing instruction.