LSI Assigned Three Patents

Data integrity in storage device cache
in presence of intermittent failures of cache memory subsystem
LSI, Corp., Milpitas, CA, has been assigned a patent (8,874,973) developed by four co-inventors for “methods and structure to assure data integrity in a storage device cache in the presence of intermittent failures of cache memory subsystem.”

The co-inventors are Brandon L. Hunt, CO Springs, CO, Luke E. McKay, Rose Hill, KS, Moby J. Abraham, Lilburn, GA, and Lakshmana M. Anupindi, Suwanee, GA.

The abstract of the patent published by the U.S. Patent and Trademark Office states: “Methods and structure for enabling re-training of a DDR memory controller in a storage device without loss of data in the DDR memory devices of the cache memory in response to detecting failure of the memory subsystem during operation of the storage device. In response to detecting a failure of the memory subsystem, the memory controller is reset without resetting the memory devices. The memory controller is then re-trained for operation with the memory device. During the re-training, self-refresh mode of the memory devices is disabled and manual refresh is performed by a processor of the storage device to thereby retain any user data in the memory device.”

The patent application was filed on Oct. 26, 2012 (13/661,369).

Storage media inter-track interference cancellation
LSI, San Jose, CA, has been assigned a patent (8,879,182) developed by seven co-inventors for the “storage media inter-track interference cancellation.“

The co-inventors are Erich Franz Haratsch, Bethlehem, PA, George Mathew, San Jose, CA, Ming Jin, Fremont, CA, Jongseung Park, Allentown, PA, Timothy W. Swatosh, Timothy B. Lund, and Carl E. Forhan, Rochester, MN.

The abstract of the patent published by the U.S. Patent and Trademark Office states: “Described embodiments provide a method of cancelling inter-track interference (ITI) from one or more sectors read from a desired track of a storage medium. A road channel reads sectors in a desired track of the storage medium. A decoder of the read channel decodes the read sectors, and if the read sectors are incorrectly recovered from the storage medium, selected sectors of a first adjacent track and a second adjacent track are read. An ITI canceller of the read channel estimates ITI in the read sectors of the desired track corresponding to the selected sectors of each adjacent track and subtracts the estimated ITI of each adjacent track from the data for the sectors of the desired track, providing updated sector data. The ITI cancelled data is replayed to the decoder, which decodes the ITI cancelled data and provides the decoded ITI cancelled data as output of the read channel.”

The patent application was filed on Aug. 22, 2012 (13/591,937).

Touchdown detection in magnetic disk storage devices
LSI, San Jose, CA, has been assigned a patent (8,873,194) developed by Xiufeng Song, San Jose, CA, and Richard Rauschmayer, Longmont, CO, for “touchdown detection in magnetic disk storage devices.“

The abstract of the patent published by the U.S. Patent and Trademark Office states: “Touchdown detection in magnetic storage devices is provided to detect contact between a storage medium and a magnetic head having an embedded contact sensor. A sample stream is obtained, which includes samples of a sensor signal output from the embedded contact sensor. The sample stream is segmented into multiple segments. A modulation depth is determined for each of the segments. A combined modulation depth is determined by combining the modulation depths of the segments using a weighting function. The combined modulation depth is compared with a threshold. A determination is made as to whether the magnetic head makes contact with the storage medium based on a result of the comparing.”

The patent application was filed on April 1, 2014 (14/242,633).