A memory system is configured to be connected to a host. The memory system includes a non-volatile first memory, a second memory, and a controller configured to manage cache data stored in the second memory in units of a segment such that each segment includes a plurality of pieces of the cache data. Each of the plurality of pieces of the cache data includes mapping information which correlates a logical address value indicating a location in a logical address space provided by the memory system to the host with a location in the first memory. At least two pieces of the cache data are arranged in one segment without a space therebetween.

A memory system includes: a memory device; a first queue suitable for queuing commands received from a host; a second queue suitable for enqueuing the commands from the first queue and dequeuing the commands to the memory device according to the FIFO scheme; and a processor suitable for: delaying enqueuing a read command into the second queue until the program operation is successfully performed when a logical address of a write command, in response to which a program operation is being performed, is the same as a logical address corresponding to the read command enqueued in the first queue; and determining whether or not to enqueue a subsequent read command, which is enqueued in the first queue after the read command, into the second queue.

Devices and techniques for efficient obfuscated logical-to-physical mapping are described herein. For example, activity corresponding to obfuscated regions of an L2P map for a memory device can be tracked. A record of discontinuity between the obfuscated regions and L2P mappings resulting from the activity can be updated. The obfuscated regions can be ordered based on a level of discontinuity from the record of discontinuity. When an idle period is identified, an obfuscated region from the obfuscated regions is selected and refreshed based on the ordering.

A memory sub-system configured to dynamically generate a media layout to avoid media access collisions in concurrent streams. The memory sub-system can identify plurality of media units that are available to write data concurrently, select commands from the plurality of streams for concurrent execution in the available media units, generate and store a portion of a media layout dynamically in response to the commands being selected for concurrent execution in the plurality of media units, and executing the selected commands concurrently by storing data into the memory units according to physical addresses to which logical addresses used in the selected commands are mapped in the dynamically generated portion of the media layout.

Systems and methods are disclosed for the intelligent scheduling of garbage collection operations on a solid state memory. In certain embodiments, a method may comprise initiating a garbage collection process for a solid state memory (SSM) having a multiple die architecture, determining an order of die access for the garbage collection process based on an activity table indicating a use of one or more die in the multiple die architecture, and performing the garbage collection process based on the determined order of die access. Garbage collection reads may be directed to idle die to avoid conflicts with die busy performing other operations, thereby improving system performance.

A method for mapping LUNs (logical unit numbers) in storage memory, performed by a storage system, is provided. The method includes determining a set of LUNs in the storage memory and generating a mapping from a logical address space to all of the LUNs in the set, based on the determining, so that each logical address in the logical address space maps to one LUN in the set. The method includes accessing one or more of the LUNs in accordance with the mapping.

Converting RAID data between persistent storage types, including: for each portion of a RAID shard of a RAID stripe: writing, to a respective plurality of source solid state drives, the portion of the RAID shard; detecting that all portions of the RAID shard have been successfully written; copying, from one of the plurality of source solid state drives to a respective target solid state drive among a plurality of target solid state drives from one of the plurality of source solid state drives, the RAID shard, where the RAID shard is copied from a source solid state drive that is different from where each other RAID shard of the RAID stripe is copied from.

Embodiments of the invention describe a system main memory comprising two levels of memory that include cached subsets of system disk level storage. This main memory includes “near memory” comprising memory made of volatile memory, and “far memory” comprising volatile or nonvolatile memory storage that is larger and slower than the near memory.

The far memory is presented as “main memory” to the host OS while the near memory is a cache for the far memory that is transparent to the OS, thus appearing to the OS the same as prior art main memory solutions. The management of the two-level memory may be done by a combination of logic and modules executed via the host CPU. Near memory may be coupled to the host system CPU via high bandwidth, low latency means for efficient processing. Far memory may be coupled to the CPU via low bandwidth, high latency means.

A technique relates to flash-optimized data layout of a dataset for queries. Selection columns are stored in flash memory according to a selection optimized layout, where the selection optimized layout is configured to optimize predicate matching and data skipping. The selection optimized layout, for each selection column, is formed by storing a selection column dictionary filled with unique data values in a given selection column, where the unique data values are stored in sorted order in the selection column dictionary. Row position designations are stored corresponding to each row position that the unique data values are present within the given selection column, without duplicating storage of any of the unique data values that occur more than once in the given selection column.

This disclosure provides for improvements in managing multi-drive, multi-die or multi-plane NAND flash memory. In one embodiment, the host directly assigns physical addresses and performs logical-to-physical address translation in a manner that reduces or eliminates the need for a memory controller to handle these functions, and initiates functions such as wear leveling in a manner that avoids competition with host data accesses. A memory controller optionally educates the host on array composition, capabilities and addressing restrictions. Host software can therefore interleave write and read requests across dies in a manner unencumbered by memory controller address translation. For multi-plane designs, the host writes related data in a manner consistent with multi-plane device addressing limitations. The host is therefore able to “plan ahead” in a manner supporting host issuance of true multi-plane read commands.