Sandisk Technologies Inc.

Bala Siva Kumar Narala

Yehuda Hahn

Ramanathan Muthiah

Narendhiran Chinnaanangur Ravimohan

A data storage device having a flash translation layer configured to handle file-system defragmentation in a manner that substantially avoids physical data movement in a flash memory. In an example embodiment, a memory controller operates to update a logical-to-physical table thereof to change association of physical addresses of sections of user data from being associated with source logical addresses to being associated with destination logical addresses of the host defragmentation requests without moving the user data in the flash memory. Such updates can reduce the number of instances in which the host addresses a non-contiguous logical-address range, which results in a beneficial reduction of the number of input/output commands sent to the data storage device and of the associated processing overhead.

Logical-to-physical mapping for defragmentation of host file system in a data storage device

A data storage device having a flash translation layer configured to handle file-system defragmentation in a manner that avoids, reduces, and/or optimizes physical data movement in flash memory. In an example embodiment, the memory controller maintains in a volatile memory thereof a lookaside table that supplants pertinent portions of the logical-to-physical table. Entries of the lookaside table are configured to track source and destination addresses of the host defragmentation requests and are logically linked to the corresponding entries of the logical-to-physical table such that end-to-end data protection including the use of logical-address tags to the user data can be supported by logical means and without physical data rearrangement in the flash memory. In some embodiments, physical data rearrangement corresponding to the file-system defragmentation is performed in the flash memory in response to certain trigger events, which can improve the input/output performance of the data-storage device.

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Kakinada, India

Bala Siva Kumar Narala