Seagate Technology Incorporated

Soon Wah Leow

Beng Wee Quak

Ming Zhong Ding

KianKeong Ooi

David L Schell

Kian Keong Ooi

Teck Khoon Lim

Song Wee Teo

KokHoe Chia

Jack Ming Teng

Kwee Teck Say

Patrick TaiHeng Wong

Daniel Eugene Hobson

Chris Thomas Settje

An apparatus and method for selecting physical cylinders (cylinders accessible for read/write operations) in a disc drive is provided. The disc drive includes at least one rotatable disc. The disc drive also includes a first head, which is positionable adjacent a first disc surface, and a second head, which is positionable adjacent a second disc surface. The first disc surface has a first plurality of greycode tracks and the second disc surface has a second plurality of greycode tracks. Each greycode track of the second plurality of greycode tracks corresponds to a different greycode track of the first plurality of greycode tracks, thereby forming a plurality of greycode cylinders, with each greycode cylinder of the plurality of greycode cylinders including a pair of corresponding greycode tracks. The physical cylinders are a subset (less than all) of the plurality of the greycode cylinders. The method of selecting the physical cylinders includes determining whether the first plurality of greycode tracks or the second plurality of greycode tracks demonstrates greater track eccentricity, to thereby obtain a maximum track eccentricity surface and a corresponding maximum eccentricity head. The maximum track eccentricity surface is one of the first and second disc surfaces and the maximum eccentricity head is a corresponding one of the first and second heads. The maximum eccentricity head is used to locate at least one of the physical cylinders.

Selecting physical cylinders in a disc drive employing discs with pre-written servo patterns

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 disc drive system and method of screening an actuator resonance includes a servo controller providing a multi-servo zone architecture. The servo controller partitions the disc into a plurality of servo zones. Each of the servo zones has a corresponding servo gain. When an actuator resonance is detected in one of the servo zones, the servo controller reduces the corresponding servo gain of the detected servo zone such that a drive with very low resonance at a certain zone does not affect the servo bandwidth of the other good zones. Accordingly, a drive with very low resonance is prevented from being scrapped. Further, the screening technique allows a drive to have an adequate servo margin for its normal operation after going through a resonance detection test.

Actuator resonance screening in disc drives

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Singapore, Singapore

Soon Wah Leow