Patent ID: 11900965
Assignee: SEAGATE TECHNOLOGY LLC
Field: Audio-visual technology (Electrical engineering)
Classification: CPC G | IPC G

Claim 7:
8. A method comprising:
writing a servo wedge onto a data storage disc having a top surface and a bottom surface, each of the top and bottom surfaces being parallel to an x-y plane;
the writing resulting in a top surface boundary of the servo wedge and a bottom surface boundary of the servo wedge;

during a disc certification event:
supporting a head pair on an actuator arm assembly while the disc rotates at a spin speed measurable in revolutions per minute (rpm);
flying the head pair at a data track located at radius R from a disc center, wherein the head pair encounters the top surface boundary of the servo wedge at a first time and wherein the head pair encounters the bottom surface boundary of the servo wedge at a second time, thereby defining a certification time difference (ΔTc) between the first and second times; and
determining a target Z-height (d1) between a first actuator arm of the actuator arm assembly and the top surface at the data track;

during a disc read/write interaction:
flying the head pair at the data track while the disc rotates at the spin speed, wherein the head pair encounters the top surface boundary of the servo wedge at a third time, and wherein the head pair encounters the bottom surface boundary of the servo wedge at a fourth time, thereby defining an operation time difference (ΔT) between the third and fourth times;

determining an amount (ΔTZ) by which the operation time difference (ΔT) is changed from the certification time difference (ΔTc); and
employing ΔTZ to move the first actuator arm toward the target Z-height (d1).