Imation Corporation

Kingston Digital, Inc.

Arunprasad Ramiya Mothilal

A method for making memory more reliable involves accessing data stored in a removable storage device by translating a logical memory address provided by a host digital device to a physical memory address in the device. A logical memory address is received from the host digital device. The logical memory address corresponds to a location of data stored on the removable storage device. A physical memory address corresponding to the local address is determined by accessing a lookup table corresponding to the logical zone.

Logical-to-physical address translation for a removable data storage device

Methods permitting erasures to be performed evenly over time in memory, thereby extending the service life of a data storage device, and devices operable to perform those methods. Erasures performed on a given physical block in memory are tracked by incrementing a corresponding erase count included in an entry associated with a logical block correlated with that physical block. Each of a plurality of physical blocks included in the memory is associated with logical zones such that each logical zone comprises a different portion of the physical blocks. An erase count indicator is determined for each logical zone. When the total number of erasures for the given physical block reaches a limit, the entry associated with the logical block correlated with that physical block is exchanged with another entry associated with a logical block correlated with a physical block in a logical zone having a lower count indicator.

Static wear leveling

Methods for extending the service life of a data storage device and devices operable to perform those methods are presented. A master lookup table block may comprise lookup table blocks and store an erase count indicator for each lookup table block. Each lookup table block may be associated with a logical zone of a memory and comprise entries. Each entry may be associated with a logical block and comprise an erase count for a physical block corresponding to that logical block. A physical block erasure may be performed on a first physical block in the memory. The physical block erasure may be tracked by incrementally increasing a first erase count. An actual erase count may be determined for the first physical block. The entry for a logical block corresponding to the first physical block may be exchanged with another entry within a different lookup table block when the actual erase count for the first physical block exceeds a threshold. The different lookup table block may have a lower erase count indicator relative to that of the lookup table block comprising the entry for the logical block corresponding to the first physical block.

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San Jose, CA, United States of America

Arunprasad Ramiya Mothilal