Western Digital Technologies, Inc.

Virtium Technology, Inc.

Lan Dinh Phan

Ho-Fan Kang

Matthew Lewis Call

Mei-Man L Syu

Jerry Lo

Dominic S Suryabudi

John A Morrison

Robert L Horn

Lyndon S Chiu

Frederick H Adi

Cliff Pajaro

Stephen P Hack

A data storage subsystem is disclosed that implements a process for storing and/or reconstructing system data, such as a system mapping table. In certain embodiments, table pages are systematically copied, or flushed, to non-volatile memory in a progressive manner, according to a fixed ratio of flushed table pages per table update trigger, thereby facilitating write and/or load efficiency. Full or partial reconstruction of a table may be performed within a bounded number of operations based on the size of the table, the ratio implemented, and/or other characteristics.

System data storage mechanism providing coherency and segmented data loading

Embodiments of this disclosure relate to improving solid-state non-volatile memory management. Embodiments improve the management of solid-state non-volatile memory by providing an execution manager responsible for controlling the timing of providing a request to a memory unit for execution. In embodiments, the execution manager traverses a list of received requests for memory access and dispatches commands for execution. In embodiments, if a request is directed to memory units which have reached a threshold for outstanding requests, the request may be skipped so that other requests can be dispatched for memory units which have not yet reached the threshold.

System and method for managing access requests to a memory storage subsystem

Systems and methods for retaining data are disclosed in which refresh copy operations are performed on data stored in non-volatile solid-state memory. A controller may be configured to maintain a list of physical memory locations, the list sorted by a least recently used criterion. The controller may select a first entry from a top of the list and perform a refresh operation to copy data stored in a current physical memory location associated with the first entry to a new physical memory location, and may remove the first entry from the top of the list and add a new entry associated with the new physical memory location to a bottom of the list. The controller may repeat the select, perform, remove and add steps for a plurality of entries in the list, and the steps may be timed such that all refresh operations are performed for all of the plurality of entries within a set period of time.

System and method for performing data retention in solid-state memory using an LRU list

Embodiments of the invention are directed to enabling concurrent commands from command requesters in a non-volatile solid-state storage subsystem in a manner that reduces contentions among the commands. Embodiments group blocks of memory into multiple sets of superblocks and associate a command requester to each superblock set. In one embodiment, the superblock sets are dynamically associated with a requester. In one embodiment, the superblock sets are dynamically associated with requesters based in part on at least one of internal memory management needs and host command throughput. In one embodiment, an erase command is executed on a superblock within a set and a simultaneous write command is executed on a superblock within another set.

System and method for reducing contentions in solid-state memory access

Embodiments of the invention are directed to enable simultaneous or nearly simultaneous execution of internal and host-issued commands in a non-volatile storage subsystem while maintaining data consistency. Embodiments maintain validity information on data residing at physical addresses as well as logical to physical address mappings in the solid-state storage subsystem. In one embodiment, a controller within the storage subsystem selectively cancels internal commands that it determines to be writing data that has been rendered invalid by another command. In one embodiment, the determination is made by consulting the validity information kept by the controller in an invalid page table.

System and method for managing execution of internal commands and host commands in a solid-state memory

Reduced spatial redundancy of lower bits data provides data protection for a flash memory having MLC NAND devices operated in page mode. An interrupted write operation of most significant bit pages can corrupt previously written data in lower bit pages. The lower bits redundant memory assists in restoring the data, using less than a full back up storage.

Solving MLC NAND paired page program using reduced spatial redundancy

System and method for multistage processing in a memory storage subsystem

Systems and methods for retaining data in non-volatile solid-state memory are disclosed in which refresh copy operations are performed on data stored in non-volatile solid-state memory. A controller can comprise a data retention module configured to issue copy commands within different periods of time and to maintain usage data on a storage subsystem. A refresh copy operation helps ensure that data written to memory retain integrity by causing data to be programmed again onto the memory. Execution of refresh copy commands may be prioritized over other commands based on a remaining length of time. One or more data structures may be used to determine memory blocks that require refresh copy operations. In one embodiment, a validity bit array is used to track blocks that contain valid data. In another embodiment, a least recently used list is used to track blocks that have been least recently written.

System and method for performing data retention in solid-state memory utilizing copy commands and usage data

In one embodiment of the invention, a flash-based/solid-state storage system with an implemented data redundancy scheme such as RAID is configured to hold parity data in a volatile memory such as RAM and write such parity data to the non-volatile flash media when a full stripe of data has been written to the media. Other embodiments in certain situations force an early write of the parity for a partial stripe that has not been fully written to the non-volatile media. Those situations may include a data access error on data in a partial stripe and a detected power loss event with a partial stripe present. Embodiments are directed to writing additional data with the parity data for the partial stripe and then later using the additional data in data recovery. This approach allows the controller to easily detect the presence of a partial stripe and handle such a stripe accordingly.

System and method for improving a data redundancy scheme in a solid state subsystem with additional metadata

The present disclosure is directed to managing write commands for a storage system implementing address indirection. In some storage systems, a mapping table that provides logical-to-physical mapping may have individual entries that each references a logical address size that exceeds the size of an atomic write to the storage media. In such systems, a write to a logical address is not atomic as it may require several discrete physical writes that may individually fail. The techniques presented employ several pre-commit and post-commit actions to save data that enables the storage system to make writes to these logical addresses atomic and prevent undue delay on powerup.

System and method for improving data integrity and power-on performance in storage devices

Embodiments of this disclosure relate to improving solid-state non-volatile memory management. Embodiments improve the management of solid-state non-volatile memory by providing a central manager responsible for receiving requests from media access requesters. In embodiments, the central manager updates requests with a physical address corresponding to a logical address for a request. In embodiments, the central manager is the only entity updating a mapping table and invalid page table for the system. In embodiments, the central manager may also throttle or prioritize requests originating from two or more requesters to change the ratio of requests executed from each requester.

Growing community of inventors

Laguna Hills, CA, United States of America

Lan Dinh Phan