Seagate Technology Incorporated

Other

Prafulla Bollampalli Reddy

Ara Patapoutian

Deepak Sridhara

Hieu Van Nguyen

Sean R Atsatt

Jimmie Ray Shaver

Hui Su

William K Weberg

Timothy V Gates

John Stuart Wright

Jeffrey Alan Miller

Richard Jay Parshall

Mark H Groo

Michelle Elaine Blankenship

Eddie Wai Pun

Mark Hubert Groo

Timothy Richard Feldman

Bernardo Rub

Jason Charles Jury

James Joseph Touchton

Peter Igorevich Vasiliev

Don M Robinson

Kathleen Anne Duncan

Marvin Mang-Yin Lum

Pervez Edul Virjee

Stanley M Schekall

Catherine Anne French

Mary Elizabeth Dunn

An apparatus may include a circuit configured to initialize a read operation to read one or more requested data segments of a respective data unit having a plurality of data segments. Based on a number of failed data segments of the requested data segments and an erasure capability of an outer code error correction scheme, the circuit may perform erasure recovery to recover the failed data segments. Based on the number of failed data segments, the erasure capability of the outer code error correction scheme, and a threshold value, the circuit may perform iterative outer code recovery to recover the failed data segments.

Efficient read and recovery with outer code

Systems and methods are disclosed for implementing sector management in drives having multiple modulation coding. A circuit may be configured to generate a data sector having a first number of bits based on a first modulation encoding scheme associated with a first location of a data storage medium, determine a difference between the first number of bits and a second number of bits corresponding to a second modulation encoding scheme associated with a second location of the data storage medium, append a number of padding bits to the data sector based on the difference, and store the data sector to the second location of the data storage medium. The data sector may be a sector reallocated from the first location to the second location. The data sector may also be an intermediate parity sector stored to a media cache region of the data storage device.

Sector management in drives having multiple modulation coding

An apparatus may include a circuit that initializes a read operation to read one or more requested data segments of a respective data unit. The circuit may generate equalized combined samples for a failed data segment of the one or more requested data segments based on first samples and second samples. In addition, the circuit may perform iterative outer code recovery for the data unit utilizing the equalized combined samples as samples for the failed data segment.

Iterative outer code recovery using data from multiple reads

Systems and methods are disclosed for minimizing reads for reallocated sectors of a data storage medium. An apparatus may be configured to selectively skip over reallocated sectors in an LBA range without interrupting a read, via generating a skip mask or by beginning the read after the reallocated sector and reading the entire track up to the reallocated sector. When a number of sectors not read from the LBA range during the read operation is less than an amount of sectors that can be recovered based on an error correction capability, the data of the reallocated sector may be reconstructed using error correction data rather than by performing a read at the reallocated sector.

Minimizing reads for reallocated sectors

Systems and methods are disclosed for performing segment-based outer code recovery at a data storage device. An apparatus may comprise a circuit configured to disable outer code error recovery, and perform a read operation spanning a plurality of segments of a data storage medium, a segment including a plurality of sectors. The circuit may identify one or more segments from the plurality of segments that have one or more sectors with an error. For an identified segment of the one or more segments, the circuit may perform a re-read operation with outer code error recovery enabled, and perform outer code recovery on sectors with an error within the identified segment.

Segment-based outer code recovery

Presented is a data channel with selectable components, such as encoders or decoders. Also, data having different data signal characteristics can be processed through a data channel based on the data signal characteristics. Further, a data channel may have independent encoding path and an independent decoding path. For example, a first data transmission having first data signal characteristics may be processed via a data channel based on a first selected set of components of the data channel and a second data transmission having second data signal characteristics different than the first data signal characteristics may be processed via the data channel using a second selected set of components in the data channel. The first selected set of components may be different than the second selected set of components, but may share one or more common components.

Multiuse data channel

A method includes generating a track description in real-time describing at least a portion of a track of a storage medium. An apparatus includes a dynamic track description generator configured to dynamically generate a track description describing a data wedge of a track on a storage medium, wherein the track description is generated at a time prior to synchronization with the data wedge.

Automatic track description generator

An implementation of a system disclosed herein provides a method of deferring decoding of a data sector received at a read channel of a storage device, in response to determining that a data sector cannot be decoded by a first decoder and storing the data sector for further processing by a second decoder.

Read channel throughput management

Values are grouped into a first set of groupings of values. Based on inner codes, the number of groupings in the first set of groupings that have at least one erroneous value is determined. If the number of groupings in the first set of groupings that have an erroneous value is fewer than a maximum number of groupings that can be corrected by outer codes, a seek operation is begun. During the seek operation, the outer codes are used to detect and correct the erroneous values that were produced during the reading of values. In other aspects, a parity section for a data section of a data storage device is dirtied before writing any data to the data section such that if writing to the data section is interrupted, the parity section will indicate that it should not be used to correct data read from the data section.

Outer code error correction

A memory medium has a plurality of tracks arranged in a plurality of sectors with each track sector having a format which does not include header fields identifying sectors or sector defects or defect management procedures. Track management apparatus identifies the track sector currently confronting a transducer; the track management being based on sector pulses (in the case of a dedicated servo system), or being calculated based on track information, an index pulse and data wedge information from previous wedges (in the case of embedded servo systems), or being derived from a lookup table. To accommodate sector defects, a defect bank contains the identity and type of each defective or spare sector. Defect management apparatus is connected to the defect bank and track management apparatus to indicate when the sector confronting the transducer is a defective or spare sector to halt data transfer to thereby skip the defective sector, or to generate an interrupt signal to the processor to transfer data between the processor and an alternate sector.

Apparatus and process for identifying sectors in a headerless sector data track

An address translation unit is provided for logical to physical address conversion. In particular, apparatus and method are described for receiving a logical cylinder head sector for a logical block address and converting it into a physical cylinder head sector. If a logical block address is received, it is converted to a physical block address and then the physical block address is converted into a physical cylinder head sector. If a logical cylinder head sector is first received, it is converted into a logical block address, and then the conversion takes place just as it would for an initially received logical block address.

Autonomous high speed address translation with defect management for

Apparatus and process for managing defective headerless sectors

A magnetic disc storage system includes a rotating magnetic disc and a read/write transducer positioned proximate a recording surface of the magnetic disc for reading and writing information on the recording surface. Data stored on the recording surface is altered based upon the address of the data. During readback, a pseudorandom number generator receives a desired address as a seed input and provides a pseudorandom number output. An XOR gate provides an XOR output in response to the pseudorandom number output and the readback signal from the read/write transducer. An error detection circuit provides a decoded data output and an error flag output in response to the XOR output. An error during readback indicated by the error flag output is indicative of an incorrect address of the readback signal in comparison to the desired address. During a write operation, data is provided to an error detector encoder circuit which provides an encoded data output to an XOR gate. A pseudorandom number generator receives the address of the data as a seed input and provides a pseudorandom number to the XOR gate. The output of the XOR gate is written on the surface of the magnetic disc by the read/write transducer.

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Longmont, CO, United States of America

Prafulla Bollampalli Reddy