International Business Machines Corporation

Hitachi Global Storage Technologies Netherlands B.v.

Western Digital Technologies, Inc.

Hgst Netherlands, B.v.

Sandisk Technologies Inc.

Other

Stmicroelectronics S.r.l.

Martin Aureliano Hassner

Barry Marshall Trager

Charles Edwin Cox

Shmuel Winograd

Satoshi Yamamoto

Tetsuya Tamura

Kirk Hwang

Nyles Heise

Arvind M Patel

Sridhar Chatradhi

Uwe Schwiegelshohn

James Lee Hafner

Roy Lee Adler

Richard Leo Galbraith

Steven Robert Hetzler

Travis Roger Oenning

Vipul Srivastava

Ward M Parkinson

Myron Dale Flickner

Jonathan Darrel Coker

Weldon Mark Hanson

Hideo Asano

Maurizio Zuffada

Roger William Wood

Nathan Franklin

Spencer W Ng

Giorgio Betti

Walter Hirt

Paul H Siegel

Francesco Chrappan Soldavini

Francesco Rezzi

Natasa Letourneaut

Ralf Kotter

Ralph Koetter

Christopher John Petti

Bruce Alexander Wilson

Peter Anthony Franaszek

John Peter Moussouris

Raj K Ramanujan

Michael Grobis

Razmik Karabed

Manfred Ernst Schabes

Kamal Emile Dimitri

Bernd Lamberts

Norman Ken Ouchi

Ehud Dov Karnin

Richard M H New

Bertrand Gabillard

Richard C Schneider

Michael Nicolas Albert Tran

Xinmiao Zhang

Rajesh Koul

Mark William Branstad

Francesco Brianti

Neil R Davie

Robert W Anderson

Gerhard P Fettweis

Thomas E Stanley

Ralph L Gee

Saurabh Deoras

Bruce P Kitchens

Thomas D Howell

Richard Michael Hamilton New

Yoshiaki Sonobe

Kei Akiyama

Christopher Scott Dudley

Luke C Lang

Tamura Tetsuya

Asao Terukina

Tohru Nozawa

Seiji Koyama

Shumel Winograd

Khaled Abdel-Ghaffar

Trung L Nguyen

Wear levelling techniques based on use of a Galois field for the logical to physical translation of data addresses for a non-volatile memory, such as an MRAM-based memory, are presented. This not only provides a wear levelling technique to extend memory life, but also adds an additional layer of security to the stored memory data. More specifically, the following presents embodiments for secure wear levelling based on a Galois field having an order based on the size of the memory. To further improve security, a randomly generated rotation of the logically address based on the Galois field can also be used.

Secure wear levelling of non-volatile memory based on Galois field circuit

Technology is disclosed for a fast ECC engine for a mixed read of MRAM cells. A codeword read from MRAM cells using a referenced read is decoded using a first ECC mode. If decoding passes, results are provided to a host. If decoding fails, a self-referenced read (SRR) is performed. The data read using the SRR is decoded with a second ECC mode that is capable of correcting a greater number of bits than the first ECC mode. The second ECC mode may have a higher mis-correction rate than the first ECC mode (for a given raw bit error rate (RBER)). However, the RBER may be lower when using the second ECC mode. Therefore, the first and second ECC modes may result in about the same probability of an undetectable error (or mis-correction).

Programmable ECC for MRAM mixed-read scheme

Apparatuses, systems, methods, and computer program products are disclosed for data rewrite operations. A non-volatile memory device comprises a non-volatile memory medium. A non-volatile memory device is configured to determine an error metric for a non-volatile memory medium in response to a read request for the non-volatile memory medium. A non-volatile memory device is configured to receive a refresh command from a controller over a bus. A non-volatile memory device is configured to rewrite data from a non-volatile memory medium during a predefined time period after receiving a refresh command in response to an error metric satisfying an error threshold.

Data rewrite during refresh window

A data storage device comprises a host interface and a storage control system coupled to the host interface. The storage control system is configured to perform a write process to write data to storage in response to one or more write operations received over the host interface from a host, determine a quality of written data produced by the write process; and in response to when the quality of the written data fails to satisfy one or more quality criteria, obtain data parity information to compensate for the quality of the written data and write the data parity information to storage.

Enhanced data protection in data storage drives

A data storage system stores a set of codewords in memory. The set of codewords are encoded in accordance with a joint nesting matrix specifying multiple layers of integrated interleaved codes, including first, second and third layers of integrated interleaved codes, and the set of codewords stored in the memory include first, second and third layers of parity information corresponding to the first, second and third layers of integrated interleaved codes. When decoding a first codeword and a first subgroup containing the first codeword fail, the system decodes a group of codewords that include two more subgroups of codewords, including the first subgroup of codewords, using the third layer parity information for the group of codewords. The second and third layers of integrated interleaved codes are configured to enable decoding of two codewords, in a subgroup of codewords, having errors beyond the correction capability of the first layer codes.

Systems, methods, and devices for encoding and decoding data using multi-layer integrated interleaved codes

In general, techniques are described for monitoring health of a head in a magnetic data storage drive. A health controller may be configured to receive multi-variate sensor signals indicative of a respective reference value at least one head parameter, wherein the respective reference value is based in part on at least one initial measurement of parameters of the head obtained at a first time, determine a respective predicted current value based at least in part on a respective fixed-drift model and the multi-variate sensor signals, determine a respective actual current value that is based at least in part on at least one current measurement of the head obtained at a second time later than the first time, determine a health status for the head, and store the health status in memory.

Magnetic storage system multi-sensor signal prediction health controller

To provide enhanced operation of data storage devices and systems, various systems, apparatuses, methods, and software are provided herein. In a first example, a data storage device is presented that performs a write process to store data on a storage medium of the data storage device responsive to one or more write operations received over a host interface. The data storage device monitors a quality of the write process and determines when the quality of the write process falls below a threshold quality. Responsive to the quality of the write process falling below the threshold quality, the data storage device indicates the quality of the write process to a data protection node for determination of data parity information that compensates for the quality of the write process, where the data parity information is provided by the data protection node for storage in a selected parity storage device.

Enhanced low overhead data protection in data storage drives

A method, apparatus, and system for implementing head degradation detection and prediction for hard disk drives (HDDs) are provided. Statistical parameter stability tests are used that are calculated as Confidence Intervals (CIs) from HDD parameter measurements. HDD parameters include, for example, change or delta in fly height (dFH), magnetic resistor resistance (MRR) head values, servo variable gain amplifier (SVGA) readback amplitude values, that are used in conjunction with two or more confidence level indicators and an Auto-Regressive Integrated Moving-Average (ARIMA) (p, d, q) predictor for head degradation detection and field failure prediction.

HDD magnetic head degradation field-failure detection and prediction

To provide enhanced operation of data storage devices and systems, various systems, apparatuses, methods, and software are provided herein. In a first example, a data storage device is presented that performs a write process to store data on a storage medium of the data storage device responsive to one or more write operations received over a host interface. The data storage device monitors a quality of the write process and determines when the quality of the write process falls below a threshold quality. Responsive to the quality of the write process falling below the threshold quality, the data storage device indicates the quality of the write process to a data protection node that determines data parity information for the data to compensate for the quality of the write process. The data storage device receives the data parity information and stores the data parity information.

Data storage devices using a two-level ECC scheme are described. Embodiments of the invention allow the recovery of sectors in a squeezed group of tracks in a that includes both a single track level ECC scheme and a track band ECC scheme that functions across the set of tracks in the band. The track band ECC scheme uses additional parity information calculated using input data from multiple tracks to allow correction across tracks.

Track-band squeezed-sector error correction in magnetic data storage devices

Data storage devices are described with an ECC system that generate additional on-demand ECC information for a previously written track to provide for correction of data errors in the track and thereby avoid having to rewrite the track. Embodiments of the invention address the squeeze-error problem that arises when writing the next (second) track in a sequence causes errors to be introduced in the adjacent previously written (first) track. In alternative embodiments the existence of the data errors in the first track can be detected by reading the track or by estimating the number of likely errors using head position data measured while writing the first and second tracks. The additional on-demand ECC information can be written on any track that is available.

Error correction with on-demand parity sectors in magnetic data storage devices

A technique for recovering of 'squeezed' sectors in a set of sequential sectors such as are used in Shingled Magnetic Recording (SMR) is described. Embodiments of the invention use a programmable erased sector recovery scheme, which is a concatenation of a 'Cauchy-type' track erasure correction code, together with a media-error correction code that generates N-weighted parity-sectors per track and is capable of replacing up to N-erased sectors per track in any possible combination.

Scalable repair block error correction for sequential multiple data blocks in a magnetic data storage device

A method, apparatus, and system are provided for implementing magnetic defect location detection on-the-fly for hard disk drives. A magnetic media readback signal of a hard disk drive is demodulated to generate phase modulation (PM) and amplitude modulation (AM) signals. A new coordinate plane defined by a combined phase modulation (PM) and amplitude modulation (AM) phasor-defect detector calculation function used to locate magnetic defects on-the-fly.

Implementing combined phase and amplitude magnetic defect detection on-the-fly

A 'write-squeeze-verify' method is used for verification of the data that has been written in the annular bands of a shingled magnetic recording disk drive. The writing of data along a track overwrites a portion of the previously written track and thus 'squeezes' the data of the previously written track to thereby form a &#x201c;shingled data track&#x201d; (SDT). The data in each SDT is read back and verified by an error correction check using error correction bits associated with the data written in the SDT, or by comparing the readback data with the data stored in memory. If the data read back is not verified, a write error counter is incremented and a write error frequency is calculated. One or more attempts to write the data can be performed. If the data in the SDT cannot be verified after the attempted rewrite(s), then a &#x201c;re-try fail&#x201d; is reported.

Shingled magnetic recording (SMR) disk drive with verification of written data

A method, apparatus, and system are provided for implementing magnetic defect classification using phase modulation for hard disk drives. A magnetic media readback signal of a hard disk drive is processed to identify predefined phase modulation (PM) characteristics to implement magnetic defect classification of magnetic media bump and pit defects.

Implementing magnetic defect classification using phase modulation

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Palo Alto, CA, United States of America

Martin Aureliano Hassner