Western Digital Technologies, Inc.

Sandisk Technologies Inc.

Jonathan Journo

Nava Eisenstein

Ramanathan Muthiah

Dinesh Kumar Agarwal

Amir Segev

Marina Frid

Igor Genshaft

Vijay Sivasankaran

Vered Kelner

Laxmi Bhoopali

Nava Singer

A controller maintains logical block address (LBA) to physical block address (PBA) mappings as mSets in a storage address table (SAT). Because the SAT may include many mappings, and, consequently, have a large size, the SAT may be stored in a distanced memory from the controller, such as a non-volatile memory device of the data storage device or a host memory buffer of a host device that is coupled to the data storage device. In order to optimize performance, a portion of the SAT may be stored as a compressed address table (CAT) in an internal memory of the controller or another volatile memory of the data storage device. During operation, the controller maintains an active range of mSets in the CAT by adding mSets to the CAT based on whether the LBA is sequential to the active range and a hit count of the active range.

Optimization of an active range of mSets stored in a compressed address table

A data storage device includes a memory device and a controller. The controller is configured to select a source block, read metadata associated with the source block and compare to a logical block address to physical block address (L2P) table, determine if a flash management unit (FMU) of the source block is valid, and add a new entry associated with the FMU into a valid FMU buffer when the FMU of the source block is determined to be valid. The controller is further configured to determine that the source block has been fully validated and select a next source block based on a valid counter. The valid counter corresponds to an amount of valid data of the next source block.

Pre-validation of blocks for garbage collection

A storage system has volatile memory for use as a cache and can extend the available caching space by using a host memory buffer (HMB) in a host. However, because accesses to the HMB involve going through a host interface, there may be latencies in accessing the HMB, To reduce access latencies, the storage system views the volatile memory and the HMB as a two-level cache. In one use case, the storage system decides whether to store a logical-to-physical address table in the volatile memory or in the HMB based on a prediction of the likelihood that the table will be updated. If the likelihood for an update is above a threshold, the table is stored in the volatile memory, thereby eliminating the access latencies that would be encountered if the table needs to be updated and is stored in the HMB.

Method and storage system with a layered caching policy

Aspects of a storage device are provided that allow a controller to leverage cache to minimize occurrence of HMB address overlaps between different HMB requests. The storage device may include a cache and a controller coupled to the cache. The controller may store in the cache, in response to a HMB read request, first data from a HMB at a first HMB address. The controller may also store in the cache, in response to an HMB write request, second data from the HMB at a second HMB address. The controller may refrain from processing subsequent HMB requests in response to an overlap of the first HMB address with an address range including the second HMB address, and the controller may resume processing the subsequent HMB requests after the first data is stored. As a result, turnaround time delays for HMB requests may be reduced and performance may be improved.

Host memory buffer (HMB) random cache access

A system and method is disclosed for detecting and correcting for errors in mapping table information stored in volatile memory of a non-volatile memory system. The method may include checking for mapping entry errors when retrieving mapping data for the non-volatile memory from a volatile memory cache. When an error is discovered, the method includes the processor generating a set of candidate mapping entries each having a different single bit difference from the mapping entry discovered to have an error. Each candidate is tested against one or more mapping data accuracy tests and, when one of the candidates is found to be a correct mapping entry based on the one or more tests, the original mapping table entry with the determined defect is replaced with the successful candidate mapping entry.

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Shaarey Tikwa, Israel

Jonathan Journo