摘要:
A method and apparatus for partial self-servo writing a disk surface in a disk drive using servo wedge propagation is provided. In one embodiment, servo information is written by a servo track writer near an outer diameter of the disk surface. The servo information is grouped into a 1× set of servo information and a 2× set of servo information. The disk drive's read head is used to read the 1× set of servo information in order to position the disk drive's write head to write servo information which is radially-aligned with the 2× set of servo information. Then, the disk drive's read head is used to read the 2× set of servo information in order to position the disk drive's write head to write servo information which is radially-aligned with the 1× set of servo information. The process is repeated on a track-by-track basis until servo information is written from the outer diameter of the disk surface to the inner diameter of the disk surface, as if it was entirely written by a servo track writer.
摘要:
A method and apparatus for partial self-servo writing a disk surface in a disk drive using servo wedge propagation is provided. In one embodiment, servo information is written by a servo track writer near an outer diameter of the disk surface. The servo information is grouped into a 1x set of servo information and a 2x set of servo information. The disk drive's read head is used to read the 1x set of servo information in order to position the disk drive's write head to write servo information which is radially-aligned with the 2x set of servo information. Then, the disk drive's read head is used to read the 2x set of servo information in order to position the disk drive's write head to write servo information which is radially-aligned with the 1x set of servo information. The process is repeated on a track-by-track basis until servo information is written from the outer diameter of the disk surface to the inner diameter of the disk surface, as if it was entirely written by a servo track writer.
摘要:
In accordance with various embodiments, a rotatable member is mounted to a spindle hub so that initial servo data previously provided to the rotatable member are eccentrically offset with respect to a rotational center of the spindle hub. Compensation vales are determined to characterize said offset, after which final servo data are provided to the rotatable member in relation to the initial servo data and the determined compensation values. The final servo data are nominally concentric with the rotational center of the spindle hub.
摘要:
A disk drive detects head touchdown based on a magnitude of a position error signal at a discrete frequency. The discrete frequency is one-half the disk rotation frequency or an integral multiple of the disk rotation frequency. The head is heated by turning on a heater at the discrete frequency, thereby injecting bias into a servo system that increases the PES magnitude. In addition, the servo system has a first transfer function for tracking the head during read and write operations and a second transfer function for tracking the head during head touchdown detection. The second transfer function has smaller vibration rejection than the first transfer function so that the disk drive is less sensitive to vibration during read and write operations than during head touchdown detection.
摘要:
Track pitch for writing tracks on a disk is determined based on an available stroke across the disk. The available stroke is identified by searching across the disk for where information can be written and read. The track pitch is determined for writing tracks on the disk based on the available stroke across the disk. Tracks are written on the disk based on the determined track pitch.
摘要:
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.
摘要:
Methods and structure for switching heads on a multiple recording surface disk drive that uses bi-directional radial writing toward a zipper zone at a middle diameter. When switching from a first head to a second head, features and aspects hereof assure that the second head will not be positioned in the zipper zone of the corresponding second surface and hence will not lose track following servo synchronization and control. In one aspect, added buffer or guard tracks having valid servo information but no data are added on either side of the zipper zone to assure that under the worst-case misalignment of surfaces the second head will not be positioned in its corresponding zipper zone when switching from the first head.
摘要:
The present invention is directed to a method and apparatus for performing a self-servo write operation in a disk drive. In one embodiment, the disk drive includes a disk surface having a read head and a write head associated therewith. Spiral servo information is written onto the disk surface using a servo track writer. The read head reads the spiral servo information and is used to position the write head, which writes a small band of final servo information onto the disk surface. The small band of final servo information may be embedded servo information. Importantly, the small band of final servo information is not written using the servo track writer. The write head is also used to write self-servo write instructions into the small band of final servo information. Subsequently, the self-servo write instructions are read and a self-servo write operation is performed using the spiral servo information.
摘要:
A control source and drivers for a thermal actuator fly height controlled heads in a disk drive system includes provisions for driving a heater element to dissipate various levels of power, and thus actuate the head by a desired amount, depending on whether the head is in a write mode or a read mode. Further, overshoot and undershoot are achieved as desired by providing initial values and equilibrium values and through the use of a control capacitor to provide a time constant to the drive signal to the heater element.
摘要:
A method and apparatus for compensating for non-linearities due to pivot bearing friction when determining embedded runout correction values during partial self-servo write of a disk drive is disclosed. In one embodiment, the disk drive includes a disk surface having a track written thereon and the track has some written-in runout. The written-in runout that is associated with high-frequencies is determined using a first technique. The written-in runout for the track that is associated with low frequencies is determined using a second technique. Results from the two techniques are combined in order to determine embedded runout correction values for the track when partial self-servo writing, in order to reduce error propagation when writing additional tracks.