Samsung Electronics Co., Ltd.

Bipinchandra V Gami

Yih Hurng Jung

Kwong-Tat Chan

Tung Thanh Nguyen

Tom S Chan

Linh Nguyen

Joe Bragg

Kwong Tat Chan

Nikolay Ivanov

Hao Ping Wen

A method for writing servo information onto a disk of a hard disk drive with a servo writer. The method includes accelerating a head to a constant velocity across a disk. The disk being defined as having an acceleration zone and a constant velocity zone. The head is then used to write a spiral servo pattern in the constant velocity zone. A final servo pattern is written in the constant velocity zone using the spiral servo pattern. A servo reference pattern is also written in the acceleration zone. The servo reference pattern is used to write a final servo pattern in the acceleration zone. The final servo pattern may be copied using a run-out cancellation algorithm to improve the accuracy of the servo pattern in the acceleration zone.

Utilization of the acceleration zone in ammonite servo writing

A method for writing servo information onto a disk of a hard disk drive with a servo writer. The disk has a circumferential index and a band of servo reference tracks. The circumferential index is detected from a clock signal generated from a clock track of the disk. The reference tracks include radial indices. A spiral servo pattern is written upon the detection of the circumferential index and a radial index. The servo writer includes a phase detector that detects changes in the relative position of the circumferential and radial indices and a delay circuit that delays the clock signal to offset such changes.

Delay clock track read back data to compensate time variance due to disk thermal expansion in spiral servo track writing

A method for writing servo information onto a disk of a hard disk drive with a servo writer. The method includes writing a plurality of spiral servo signals with a head. The spiral servo signals are used to write servo patterns using at least one timing window. The timing window is adjusted using a position error signal generated from the spiral servo signals. The adjusted timing window is then used to write servo patterns onto the disk. Adjusting the timing window compensates for irregularities in the spiral servo signals.

Window timing adjustment for spiral bursts

Growing community of inventors

Northridge, CA, United States of America

Bipinchandra V Gami