Abstract: A non-volatile storage system is disclosed which provides a mapping table which includes a granularity which does not correspond to the page size of a non-volatile storage array. A reduced mapping table granularity enables more than one mapping entry to exist in a single page on the solid-state array. A write command which does not exceed a mapping table entry can invalidate only a portion of the written page, and can be combined with a second write command to write a new page of the solid-state array.

Abstract: A non-volatile storage system is provided with reduced delays associated with loading and updating a logical-to-physical mapping table from non-volatile memory. The mapping table is stored in a plurality of segments, so that each segment can be loaded individually. The segmented mapping table allows memory access to logical addresses associated with the loaded segment when the segment is loaded, rather than delaying accesses until the entire mapping table is loaded. When loading mapping segments, segments can be loaded according to whether there is a pending command or by an order according to various algorithms.

Abstract: 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.

Abstract: 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.

Abstract: Embodiments of the invention provide a storage subsystem comprising a non-volatile solid-state memory array and a system operation module for managing memory operations. The system operation module is configured to store system operation data in a data structure that includes linked lists for storing system operation data, with at least some lists including entries referencing blocks in the solid-state memory array belonging to a category. The system operation module is further configured to (1) move a particular entry from a first linked list to a second linked list when a block referenced by the particular entry in the first linked list has met a condition for being classified in a new category that is different from that of the blocks referenced by entries in the first linked list, and (2) update entries within the first and second linked lists so that the dependencies in the linked lists are maintained.

Abstract: 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.

Abstract: Systems and methods for retaining data in non-volatile solid-state 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, which minimizes the risk of data error caused by electron leak in the non-volatile solid-state memory. 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.

Abstract: A non-volatile semiconductor memory is disclosed comprising a memory device including a memory array having a plurality of blocks, each block comprising a plurality of memory segments. A plurality of logical block address (LBA) ranges are defined each identifying a plurality of LBA addresses, wherein at least one block is assigned to each LBA range. A plurality of write commands are received from a host, wherein each write command identifies at least one LBA. Data is written for each write command to the memory device. During a garbage collection operation, a memory segment storing valid write data is identified to be relocated, and the valid write data is relocated to a memory segment in a block of the corresponding LBA range.