Seagate Technology Incorporated

Song Wee Teo

Beng Wee Quak

Teck Khoon Lim

Myint Ngwe

Qiang Bi

Joshua Ward Christensen

Quek Leong Choo

Jose Mari Toribio

Kok Hoe Chia

Tze Pin Chin

Chi Sern Georgie Tan

Renee Depew

Heather Lee Mallett

Phan Linh Nguyen

Wei Chen Lau

David Allan Thorsvik

Tim Rausch

Mehmet Fatih Erden

KianKeong Ooi

KokHoe Chia

ChengYi Guo

Beng Theam Ko

Kwee Teck Say

Antonia Tsoukatos

Fong Kheon Chong

Swee Kieong Choo

Jose Mari Corral Toribio

Liu Li

Prasanna Manja Ramakrishna

Lan Xia

Soon Wah Leow

Bernard Tuang Liang Lim

Benjamin W Parish

Morovat Bryan Tayefeh

Kok Seng Lim

Sai Sian Hon

Ben Niu

The technology disclosed herein provides a method for generating an on-cylinder limit (OCLIM), the method including performing servo certification of a plurality of drives in a storage device to generate servo adaptive parameters (SAPs) by heads, generating a plurality of read adjust parameters (RAPs) by heads for the plurality of drives, generating an interim OCLIM value based on the SAPs by heads and RAPs by zones, and operating a disc drive write element using the interim OCLIM value.

Flexible on-cylinder limit for drive performance management

A method for performing a flaw scan test on a hard disk drive is disclosed. The hard disk drive includes a magnetic recording medium and spindle motor associated with a predetermined rated speed. The method includes writing a test pattern to the magnetic recording medium while operating the spindle motor at a speed greater than the predetermined rated speed. The method also includes reading the test pattern at the greater speed and detecting flaws in response to reading the test pattern.

High rpm hard disk drive testing

Method and apparatus for positioning shingled magnetic recording (SMR) tracks on a rotatable data storage medium. In some embodiments, a first band of partially overlapping tracks is written the medium at a first track pitch. An adjacent, second band of partially overlapping tracks is written to the medium at the first track pitch. The second band has a first written track at a second track pitch with respect to a last written track in the first band. The second track pitch is determined in response to an error rate established for a test track using an adjacent track written at the first track pitch.

Shingled magnetic recording interband track pitch tuning

The disclosed technology provides techniques for mitigating write-to-write bit error rate fluctuations that decrease accuracy of write precompensation (WPC) tuning. According to one implementation, such write-to-write bit error rate fluctuations are mitigated if a predetermined pattern is written at a particular radial offset from a target data track prior to testing a WPC register in association with the target data track. Selection of the particular radial offset can be performed according to an iterative offset track clean-up disclosed herein.

Noise mitigation for write precompensation tuning

A method of tuning a bias parameter for a magnetoresistive head in a data storage system includes the step of identifying, from multiple possible bias parameter values, a smallest bias parameter value for the magnetoresistive head which both maintains a bit error rate above a predetermined threshold bit error rate, and which satisfies a second criteria. The method then includes the step of setting an operational bias parameter value for the magnetoresistive head to the identified smallest bias parameter value. Also disclosed are data storage systems, or controllers which are connectable to or included with data storage systems, configured to implement the methods.

Method and apparatus for tuning a magnetoresistive bias parameter in a data storage system

A data storage device has a plurality of head/surface combinations with different data track densities on at least two surfaces. A minimum head quality is established for the data storage apparatus. Head quality is identified for each of the heads at each of a plurality of track densities. A tuned track density is selected for each surface based on the track density that corresponds to a head quality.

Tuning track density for data storage device

A logical-to-physical head map is built upon each power up of a disc drive. After powering the controller and disc drive spindle motor, a bias current is iteratively supplied to the read heads in succession. A representation of the voltage across each read head is stored in a fault register for comparison to a threshold and a &ldquo;good&rdquo; or &ldquo;bad&rdquo; fault status is stored for each head. A logical-to-physical head map is defined based on the number of logical heads, which in turn is based on the disc drive serial number. Each of the logical heads in the logical-to-physical head map is associated to a respective one of the heads having a &ldquo;good&rdquo; fault status to construct the logical-to-physical head map in the controller memory.

Disc drive power-up process including head mapping

A bias current for a magnetoresistive read head is selected by defining a tuning range based on a maximum and a minimum bias current value for the head. A plurality of read operations are iteratively performed using a different bias current value over the tuning range for each iteration. The results of each read iteration are measured and a bias current is selected on the basis of the read error rates, and particularly those bias currents associated with the lowest read error rate.

Method and apparatus for adaptive tuning bias current for magnetoresistive head

A disc drive production process automatically configures the disc drive to a suitable capacity based upon the data transfer capability of each of the head/disc surface combinations in the drive. The error rate of each of the head/disc surface combinations is determined as a function of the bit density of the disc surface. Based on the data transfer capability of the head/disc surface combinations, one of three drive configuration schemes is selected. A variable BPI (bits per inch) scheme reduces the data rate of a weak head/disc surface combination while increasing the data rate of a strong head/disc surface combination. If the drive contains one very weak head/disc surface combination, a head depopulation scheme disables the very weak head. If the drive contains two or more very weak heads, a de-frequency scheme reduces the overall capacity of the drive.

Proposal of capacity tuning in the production process of storage disc drives

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Singapore, Singapore

Song Wee Teo