International Business Machines Corporation

Hitachi Global Storage Technologies Netherlands B.v.

Daniel James Malone, Sr

Steven Robert Hetzler

David H Jen

George Anthony Dunn

Scott Arthur Thomas

Blake O Finstad

Kishan Kumar Kumbla

Jay Michael Mosbrucker

Peter Kui Ho

Paul M Cisewski

A method and apparatus for providing a marker at the end of the adaptive self-servowrite process for adaptive formatting via the self-servowrite process. The mark is used later in the drive manufacturing process to identify the number of tracks written on the surface and thus determine the appropriate format to use in the drive.

Method and apparatus for providing a marker for adaptive formatting via a self-servowrite process

A system and process for constructing a magnetic storage drive capable of single pass self-servowriting. A plurality of heads are sorted, or 'binned,' into classifications based on at least an approximate magnetic width of each head. Only heads from a single classification are installed in a particular disk drive system. A track overlap value is calculated, preferably empirically, for the approximate magnetic widths of typical heads in the single classification. The overlap value is used to determine a track spacing utilized during a self-servowriting process.

Adaptive track count determination for a self-servowritten disk drive

A system and method for managing servo defects in a data storage device. During operation of the device, a servo sector recorded on a medium is identified. A lookup is performed in a servo defect table resource to determine whether the servo sector contains defective servo information. A responsive servo control action is taken if the servo sector is found to contain defective servo information. Media having servo defect information recorded thereon are also disclosed.

Method and apparatus for servo defect management

The performance capability of different heads that are part of the same hard disk drive (HDD) are utilized by an adaptive format that includes a plurality of storage zones and at least one reset zone that are distributed along a radius of the hard disk such that a reset zone is disposed between two adjacent storage zones. Each storage zone has a plurality of associated data tracks and each reset zone includes a plurality of data tracks. The number of data tracks associated with each respective storage zone is based on a performance capability of a head associated with the hard disk and includes at least one data track of at least one reset zone adjacent to the storage zone when the number of data tracks associated with the storage zone exceeds the number of data tracks that are between each reset zone adjacent to the storage zone.

Adaptive data format method integrating spare sectors

The present invention provides a system, method and data format wherein a redundant sync byte or group of sync bytes is provided in a data sector at a distance sufficient to isolate the redundant sync byte from the primary sync byte in the event of multiple byte defects. In a first embodiment, a redundant sync byte, or group of sync bytes, is provided in the AGC field preceding the primary sync region. Upon failure to detect the primary sync byte, an attempt is made on a subsequent revolution to read the secondary sync byte, either by holding the AGC gain prior to reaching the data block, or initiating an &ldquo;early read&rdquo; just prior to reaching the data block. In a second embodiment of the invention, the redundant sync byte is provided within the data field subsequent to the primary sync region. On failing to detect the primary sync byte, the secondary sync byte can be read immediately or can be postponed until a subsequent revolution. The missed first data region is reconstructed using ECC information. In third and fourth alternative embodiments, a secondary sync byte is provided either between the primary sync byte and the start of data or between the primary sync byte and AGC field.

System and method for providing nonadjacent redundancy synchronization bytes

A method is described for storing data on a target track of a recordable medium in a storage device via a magnetic write head therein. The storage device has an operating parameter having an operational range with extreme at which the writing of data to said device is prohibited. A first threshold within said range is defined and proximate said first extreme and delimits a first operational subrange. The method including the steps of: monitoring said operating parameter; and determining whether the monitored parameter lies within said first subrange and if so, performing a first predetermined operation to compensate for deleterious effects on data storage caused thereby.

Method and system for writing data to a magnetic storage device in a relatively cold or hot environment

A direct access storage device (DASD) servo control system controls movement of a magneto-resistive (MR) read/write head in response to a readback signal generated when the MR head repeatedly passes adjacent multiple servo fields and data fields of the recording medium. The servo control system receives multiple data samples, detects a thermal asperity in the readback signal when the MR transducer is adjacent a servo field of the recording medium, determines that the servo field data samples affected by the thermal asperity are invalid due to possible data errors, and operates a servo demodulator in response to the servo field thermal asperity before the MR transducer is next adjacent the servo field. In a DASD with a rotating disk, for example, the thermal asperity response can be implemented before one revolution of the disk has been completed after the thermal asperity is encountered. This permits data samples that have been corrupted by the thermal asperity to be ignored from servo processing, thereby reducing the uncertainty in the servo information being processed. If desired, the response can be implemented before the next servo sector is encountered. In this way, the DASD more effectively utilizes storage system resources and, in particular, handles thermal asperities more efficiently.

Thermal asperity pointer for servo sector

The present invention provides a system, method and data format wherein a redundant sync byte or group of sync bytes is provided in a data sector at a distance sufficient to isolate the redundant sync byte from the primary sync byte in the event of multiple byte defects. In a first embodiment, a redundant sync byte, or group of sync bytes, is provided in the AGC field preceding the primary sync region. Upon failure to detect the primary sync byte, an attempt is made on a subsequent revolution to read the secondary sync byte, either by holding the AGC gain prior to reaching the data block, or initiating an 'early read' just prior to reaching the data block. In a second embodiment of the invention, the redundant sync byte is provided within the data field subsequent to the primary sync region. On failing to detect the primary sync byte, the secondary sync byte can be read immediately or can be postponed until a subsequent revolution. The missed first data region is reconstructed using ECC information. In third and fourth alternative embodiments, a secondary sync byte is provided either between the primary sync byte and the start of data or between the primary sync byte and AGC field.

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San Jose, CA, United States of America

Daniel James Malone, Sr