Abstract: A first data set is written to first memory units identified as having a higher data reliability and a second data set is written to second memory units identified as having a lower data reliability than the first memory units. In some cases, the second data set may include metadata or redundancy information that is useful to aid in reading and/or decoding the first data set. The act of writing the second data set increases the data reliability of the first data set. The second data set may be a null pattern, such as all erased bits.

Abstract: Method and apparatus for managing a memory, such as but not limited to a flash memory. In accordance with some embodiments, initial state information is stored which identifies an actual state of a garbage collection unit (GCU) of a memory during a normal operational mode. During a restoration mode after a memory power cycle event, a virtualized state of the GCU is determined responsive to the initial state information and to data read from the GCU. The memory is transitioned from the restoration mode to the normal operational mode once the virtualized state for the GCU is determined.

Abstract: Method and apparatus for managing a memory, such as but not limited to a flash memory. In accordance with some embodiments, user data and associated metadata are stored in a memory. The metadata are arranged as a first sequence of snapshots of the metadata at different points in time during the operation of the memory, and a second sequence of intervening journals which reflect updates to the metadata from one snapshot to the next. Requested portions of the metadata are recovered from the memory using a selected snapshot in the first sequence and first and second journals in the second sequence.

Abstract: Method and apparatus for managing data in a memory, such as but not limited to a flash memory. In accordance with some embodiments, a memory is provided with a plurality of addressable data storage blocks which are arranged into a first set of garbage collection units (GCUs). The blocks are rearranged into a different, second set of GCUs responsive to parametric performance of the blocks.

Abstract: Representative locations of a non-volatile, solid-state memory of an apparatus store characterization data. An event during which elapsed time is not measured by the apparatus is determined. In response to the event, temporal degradation of the non-volatile, solid-state memory during the event is estimated based on electrical characteristics of the representative locations.

Abstract: A host read request affects a request address range of a main storage. A speculative address range proximate to the request address range is defined. Speculative data stored in the speculative address range is not requested via the host read request. A criterion is determined that is indicative of future read requests of associated with the speculative data. The speculative data is copied from the main storage to at least one of a non-volatile cache and a volatile cache together with data of the host read request in response to the criterion meeting a threshold. The non-volatile cache and the volatile cache mirror respective portions of the main storage.

Abstract: A new segment of data is copied to a volatile, primary cache based on a host data read access request. The primary cache mirrors a first portion of a non-volatile main storage criterion is determined for movement of data from the primary cache to a non-volatile, secondary cache that mirrors a second portion of the main storage. The criterion gives higher priority to segments having addresses not yet selected for reading by the host. In response to the new segment of data being copied to the primary cache, a selected segment of data is copied from the primary cache to the secondary cache in response to the selected segment satisfying the criterion.

Abstract: Host read operations affecting a first logical block address of a data storage device are tracked. The data storage device includes a main storage and a non-volatile cache that mirrors a portion of data of the main storage. One or more criteria associated with the host read operations are determined. The criteria are indicative of future read requests of second logical block address associated with the first logical block address. Data of the at least the second logical block address is copied from the main storage to the non-volatile cache if the criteria meets a threshold.

Abstract: Apparatus and method for data management in a memory, such as but not limited to a flash memory array. In accordance with some embodiments, a plurality of data sets in a memory are identified as having a common data content and different physical addresses in the memory. A selected one of the data sets is marked as valid data and the remaining data sets are marked as stale data responsive to evaluation of at least one variable parameter associated with the physical addresses at which the data sets are respectively stored.

Abstract: Method and apparatus for managing data in a memory, such as a flash memory array. In accordance with some embodiments, a first block of data is written to a group of memory cells at a first memory location in single-level cell (SLC) mode. The first block of data is copied from the first memory location to a group of memory cells at a second memory location to provide a backup copy of the first block of data during a protected mode of operation. A second block of data is subsequently overwritten to the group of memory cells at the first memory location so that the first memory location stores both the first and second blocks of data in multi-level cell (MLC) mode.

Abstract: Apparatus and method for data management in a memory, such as but not limited to a flash memory array. In accordance with some embodiments, a first hash value associated with a first set of data stored in a memory is compared to a second hash value associated with a second set of data pending storage to the memory. The second set of data is stored in the memory responsive to a mismatch between the first and second hash values.

Abstract: A tiered memory system includes a memory controller for a primary memory and a secondary memory, where the secondary memory is used as a cache for the primary memory. The memory controller is configured to cause redundant data that is stored in the primary memory of the memory system to be stored in first memory locations of the secondary memory. The controller causes data that is not stored in the primary memory to be stored in second memory locations of the secondary memory. The second memory locations have at least one of lower bit error rate and higher access speed than the first memory locations.

Abstract: A method and apparatus for rebuilding a data set. In accordance with some embodiments, a data storage device is coupled to a host. An error condition associated with a memory of the data storage device is detected. Data stored in a first portion of the memory unaffected by said error condition is transferred to the host. A communication signal is output to the host that indicates that data stored in a second portion of the memory affected by said error condition will not be transferred to the host. The host reconstructs the data stored in the second portion of the memory responsive to the communication signal.

Abstract: The present disclosure provides a data storage system. In one example, the data storage system includes a data storage media component having a plurality of data storage locations. A first set of the plurality of data storage locations are allocated for a main data storage area. The data storage system also includes a controller configured to define a write cache for the main data storage area by selectively allocating a second set of the plurality of data storage locations.

Abstract: Method and apparatus for managing data in a memory, such as a flash memory array. In accordance with various embodiments, data are stored in a first location in a memory, and read from the first location a selected number of times. At least one parameter associated with the first location is measured after the data are read the selected number of times. The data are thereafter migrated to a second location in the memory responsive to the measured parameter indicating a presence of read disturbance in the data in the first location.

Abstract: In general, this disclosure relates to garbage collection in a storage device. Aspects of this disclosure describe techniques to identify one or more candidate memory storage blocks that should be recycled during garbage collection. The one or more candidate memory storage blocks may be identified based at least on monitored soft metrics of the candidate memory storage blocks. During garbage collection, the identified one or more candidate memory storage blocks may be recycled to free up storage space.

Abstract: In general, this disclosure relates to storage of logical blocks in a storage device. Aspects of this disclosure describe techniques to monitor the frequency of access of one or more logical blocks referenced by one or more logical block addresses. Based on the frequency of access, in non-limiting aspects of this disclosure, a controller may select one or more physical blocks of a common memory storage block. The storage device may store the logical blocks in the selected physical blocks.

Abstract: Method and apparatus for handling data in a data storage device. In accordance with some embodiments, a memory space with a plurality of garbage collection units (GCUs) that are each arranged into pages of memory that store user data identified by logical addresses (LAs) and each GCU has a metadata region that stores metadata that correlates the LAs with physical addresses (PAs). A header region in each page of memory stores a bitmask and a sequence map of the LAs in each page that are used by a log manager to creates a bitmask table stored in a first cache and a hierarchical log stored in a second cache. The bitmask table and hierarchical log are used to determine when the LAs stored in the selected GCU are stale, and update the bitmask for each page in the selected GCU after the stale data has been erased.

Abstract: A data structure is formed that references a garbage collection metric for each of a plurality of associated garbage collection units of a flash memory device. Each garbage collection metric is based on one or more device state characteristics of the associated garbage collection unit. In response to a threshold change in the one or more device state variables, a region of interest within the data structure is sorted based on the garbage collection metrics. One or more garbage collection units are selected for garbage collection operations from the sorted region of interest.

Abstract: Method and apparatus for managing metadata associated with a data storage array. In accordance with various embodiments, a group of user data blocks are stored to memory cells at a selected physical address of the array. A multi-tiered metadata scheme is used to generate metadata which describes the selected physical address of the user data blocks. The multi-tiered metadata scheme provides an upper tier metadata format adapted for groups of N user data blocks, and a lower tier metadata format adapted for groups of M user data blocks where M is less than N. The generated metadata is formatted in accordance with a selected one of the upper or lower tier metadata formats in relation to a total number of the user data blocks in the group.