Western Digital Technologies, Inc.

Frederick H Adi

Jerry Lo

Lyndon S Chiu

Lan Dinh Phan

Ho-Fan Kang

Stephen P Hack

Embodiments of the invention include systems and methods for recovering the system status and maintaining drive coherency after an unexpected power loss. In particular, these systems and methods reduce overhead for maintaining drive coherency by providing for pre-allocation of groups of write addresses and recording the pre-allocated groups of addresses to the non-volatile memory. Write processes can write to the pre-allocated group of addresses while the next group of addresses are pre-allocated and recorded to non-volatile memory.

Power-safe data management system

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

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 and log pages are systematically copied, or flushed, to non-volatile memory in an interleaving manner according to a fixed ratio of log pages to table pages, thereby facilitating coherency of data. Full and/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.

Storing and reconstructing mapping table data in a data storage system

A data storage system is disclosed that utilizes garbage collection and hybrid self-mapping for managing system data. In one embodiment, a system data region having an amount of valid system data that is below a threshold is freed. Write amplification associated with managing and storing system data can be reduced at least in part because only valid system data can be copied during garbage collection of the selected region. Mapping information associating system data with physical locations in non-volatile storage where system data is stored can be generated, which can reduce system data reconstruction time during start-up of the data storage system. Increase in efficiency and reduction in startup and initialization time can be attained.

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Costa Mesa, CA, United States of America

Frederick H Adi