Western Digital Technologies, Inc.

Hgst Netherlands, B.v.

Sridhar Chatradhi

Martin Aureliano Hassner

Satoshi Yamamoto

Jordan Asher Katine

Bernd Lamberts

Pankaj Mehra

Kirk Hwang

Natasa Letourneaut

Jonathan Darrel Coker

Roger William Wood

Rajesh Koul

Anthony Edwin Welter

Saurabh Deoras

Kei Akiyama

Ryan Matthew Schulz

Disclosed herein are magnetic storage media with embedded disconnected circuits, and magnetic storage systems comprising such media. A magnetic storage media comprises a recording layer comprising a storage location, and an embedded disconnected circuit (EDC) configured to assist in at least one of writing to or reading from the storage location in response to a wireless activation signal. A magnetic storage system comprises a signal generator configured to generate a wireless activation signal, a magnetic storage media with a plurality of storage locations, and a write transducer and/or a read receiver. The magnetic storage media has at least one EDC configured to assist in writing to and/or reading from at least one of the plurality of storage locations in response to the wireless activation signal.

Embedded disconnected circuits in magnetic storage media of data storage devices

Disclosed herein are methods of using embedded disconnected circuits (EDC) in magnetic storage media to assist in reading data from and writing data to the magnetic storage media. A wireless activation signal is used to activate an EDC in a magnetic storage media. Once activated, the EDC may assist to record data in and/or read data from one or more memory locations of the magnetic storage media.

Methods of using embedded disconnected circuits in magnetic storage media of data storage devices

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

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

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

Approaches for an emergency power off (EPO) power island, for saving critical data to non-volatile memory in the event of an EPO condition, for use in a hard-disk drive (HDD) storage device. The EPO power island includes a controller for detecting an EPO condition. A voltage regulator supplies power from spindle motor back EMF only to the EPO power island and to the non-volatile memory. Thus, the remainder of the hard drive controller (HDC) is isolated from the EPO power island so that it will not corrupt the data as the HDC's power supply is decaying. Using the power provided by the voltage regulator, the EPO power island transfers critical data from a memory internal to the island to a non-volatile memory external to the island, such as to a flash memory chip.

Emergency power off (EPO) island for saving critical data to non-volatile memory

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.

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San Jose, CA, United States of America

Sridhar Chatradhi