Abstract: Systems and methods are disclosed for writable servo zone overlap regions on a disc memory. An apparatus may comprise a controller configured to determine a servo gate (sgate) timing for an overlap zone including servo patterns of a first servo super zone and a second servo super zone of a disc memory, the sgate timing based on servo pattern timing for the first servo super zone and the second servo super zone. The controller may initiate writing to the overlap zone based on the sgate timing. The controller may also reduce the impact of servo pattern frequency change between zones by calculating a trajectory error prior to the crossing, and providing 1/X of the trajectory error into a servo feedback loop for a following X servo sampling points.

Abstract: Dynamically detecting off-track errors in a disk drive by adjusting transducer head position control parameters in response to shock events. In an embodiment, shock events with large magnitude trigger a severe shock timer which lengthens the write fault before write operations resume. In another embodiment, a lower shock threshold is used following an initial shock event. In yet another embodiment, a lower shock threshold is used if an accumulated average position error of the transducer head is large.

Abstract: Dynamically detecting off-track errors in a disk drive by adjusting transducer head position control parameters in response to shock events. In an embodiment, shock events with large magnitude trigger a severe shock timer which lengthens the write fault before write operations resume. In another embodiment, a lower shock threshold is used following an initial shock event. In yet another embodiment, a lower shock threshold is used if an accumulated average position error of the transducer head is large.

Abstract: A method and apparatus for determining embedded runout correction values when self-servo writing or partial self-servo writing is disclosed. In one embodiment, a disk surface, which has servo information written thereon, is provided. The servo information is grouped into 1x servo sectors and 2x servo sectors, and the 1x servo sectors and the 2x servo sectors form a plurality of tracks. A read head servos on the 1x servo sectors associated with a track. Both position error signals due to repeatable runout for the 1x servo sectors and information related to position error signals due to repeatable runout for the 2x servo sectors are determined, while servoing on the 1x servo sectors. Embedded runout correction values for the 1x servo sectors and the 2x servo sectors are calculated.

Abstract: A method and apparatus for automatically determining an embedded runout correction threshold for a disk drive are disclosed. In prior systems, embedded runout correction thresholds were set for all disk drives in a production run. The present invention provides a technique for automatically determining an embedded runout correction threshold on a drive-by-drive basis, instead of a production run of drives basis.

Abstract: A method and apparatus for dynamically detecting write fault errors is provided. According to the invention, transducer head control parameters are adjusted according to observed events. For instance, off-track events of a certain magnitude may trigger the implementation of a severe shock timer, which lengthens the delay between the off-track event and allowing write operations to resume, as compared to the standard off-track timer. According to another embodiment of the present invention, a lower write fault threshold is implemented following an off-track event of sufficient magnitude. According to yet another embodiment of the present invention, the average or accumulated position error of the transducer head is monitored, and a lower write fault threshold implemented if the average position error exceeds a threshold value.