International Business Machines Corporation

Hitachi Global Storage Technologies Netherlands B.v.

Hgst Netherlands, B.v.

Nyles Heise

Martin Aureliano Hassner

Hideo Asano

Tetsuya Tamura

Walter Hirt

Hung M Vu

Steven Robert Hetzler

David Robison Hall

Barry Marshall Trager

Vipul Srivastava

William Guthrie

A system and method for providing a command queue selection scheme by selecting commands by giving preference to commands based on the power consumption characteristics the command. In one embodiment the selection scheme involves calculating the value of the cost of energy saving associated with the access of a command by an evaluation function Costi=EAT+C&#xd7;F1 (seek distance, latency). C is a dynamically adjustable power control function that determines how much power decreases with the selection of a particular command and F1 is a functional calculation of the power consumption value associated with the particular command. In one embodiment commands with low power consumption will be accessed in preference to commands with shorter seek distance.

Method and system for reducing power consumption by command selection in a hard disk drive

Methods and apparatus of the present invention allow for interpolated Just in Time (iJIT) seek command control of hard drive actuators.

Interpolated just-in-time seek trajectories

Techniques for correcting data bytes on a data storage disk that have been rewritten are provided. A data storage system generates a long block membership (LBM) byte for each sector. The LBM bytes indicates whether the sector is part of a block of sectors. A data storage system can determine whether a failed sector is part of a long block. The data storage system adds the LBM contributions to the CRC and ECC bytes and then attempts to correct the failed sector. If the correction process is successful, the data storage system declares a miscorrection. If the error is not successfully corrected, the data storage system again adds the LBM contributions to the CRC and ECC bytes and then attempts to correct the failed sector. If the correction process is successful, the data correction is accepted if the error pattern and the check byte overlap is greater than a threshold.

Direct partial update of CRC/ECC check bytes

A method and an apparatus encodes and decodes blocks having a predetermined number of sectors of data bytes to detect and correct data bytes in error in each sector of a block. The method and the apparatus generates sector level check bytes for each sector in the block responsive to the data bytes in each sector according to a first level of an error correction code, and generates block level check bytes for a predetermined sector in the block responsive to the sector level check bytes of various sectors, including the predetermined sector, according to at least a second level of the error correction code. The method and apparatus processes the block to detect and correct data bytes in error in each sector within the capability of the sector level check bytes, to detect and correct data bytes in error in the at least two sectors that exceed the correction capability of the sector level check bytes but within the correction capability of the block level check bytes, or to indicate that the data bytes in error in the at least two sectors exceed the correction capability of each of the sector level check bytes and the block level check bytes. The method and apparatus improves signal quality for long streams of information having multiple sequential physical blocks of data bytes, such as audio visual information, with a low check byte overhead while being compatible with conventional 512 data byte sized sectors and conventional single sector error correction code processes.

Multiple level (ML), integrated sector format (ISF), error correction code (ECC) encoding and decoding processes for data storage or communication devices and systems

An encoding system and associated method protect against miscorrection due to parity sector correction in, for example, an on-drive RAID system. The system adds a parity cluster block, which itself is a complete, C3-protected cluster. Having the cluster level, C4 level correction, by parity sectors, checked and verified by C3 checks that have high reliability level, as well as the capability for checking consistency of a cluster block, even in the presence of 'jami' errors, makes this possibility unlikely. A scrub algorithm avoids read-modify-write operations by deferring the completion of the C2 and C3-ckecks until the storage device is idle.

On-drive integrated sector format raid error correction code system and method

A method for aging queued commands in a data storage device, wherein a next command is selected from the queued commands based on a combination of an expected access time (EAT) and an incentive term. The incentive term provides for selection of older ones of the queued commands that have larger EATs, instead of younger ones of the queued commands that have smaller EATs. Preferably, the value of the incentive term begins at zero, remains at zero for some number of queue sorts (which are performed before a command is selected for execution), and then increases continuously for some number of queue sorts or indefinitely. Both the incentive term's starting value and the rate at which it increases ate user-selectable parameters, and thus can be used to control service time and throughput in the disk drive's queue.

Command aging method for data storage devices

A packet-frame generator for creating an encoded packet frame comprising encoded control data and encoded utilizable data. A non-encoded packet frame comprising non-encoded control data and non-encoded utilizable data is providable by an assembling means. The packet-frame generator comprises a modulation encoder for encoding the non-encoded control data by a first modulation code and the non-encoded utilizable data by a second modulation code thereby providing the encoded packet frame.

Packet-frame generator for creating an encoded packet frame and method thereof

A generalized method for dynamically deriving configuration information from a set of given parameters for detecting binary-valued sequences from (d, k) partial-response (PR) coded waveforms of predetermined shape, for applying the derived information to configure a processor, and for operating the configured processor as a PR detector.

Generalized method and means for defining and operating a (d, k) partial-response ML detector of binary-coded sequences

A method and means for reducing high-duty-cycle unconstrained binary signal sequences in storage and communications processes and systems by invertibly mapping such sequences into a (1, k) rate &frac23; RLL codestream constrained to a duty cycle substantially approximating one-third. That is, binary sequences ordinarily mapping into high-duty-cycle RLL-code sequences are either inhibited from repeating indefinitely or excluded.

Method and means for invertibly mapping binary sequences into rate 2/3 (1,K) run-length-limited coded sequences with maximum transition density constraints

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San Jose, CA, United States of America

Nyles Heise