摘要:
A method for determining embedded runout correction (ERC) values using iteration and variable gain in a disk drive. A disk has a track written thereon, an ERC value is determined for a servo sector on the track using variable gain, and the variable gain decreases based on the number of revolutions of the disk.
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.
摘要:
A method and apparatus for controlling the position of a disk drive transducer head relative to a target track are provided. An oversampled control output allows frequencies that are higher than the Nyquist frequency of the servo control system to be filtered. The system initiates a plurality of control outputs during a single sampling period, allowing the use of a single processor interrupt for each sampling period. The outputs initiated during a single sampling period may be of unequal length. In addition, the outputs may be proportioned so that the total control energy provided to the actuator is equal to the control energy that would be provided by control outputs initiated every one-half sampling period.
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:
Performing embedded runout correction for a track on a rotational data storage disk includes measuring written-in runout for the track, selecting a number of revolutions in response to the measured written-in runout of the track, calculating embedded correction values for the track for the selected number of revolutions of the rotational data storage disk, and storing the embedded correction values.
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:
The present invention is directed to a method and apparatus for detecting and monitoring a bi-state head when self-servowriting a disk drive. In one embodiment, an integration window is opened about an expected time that a read head will read spiral servo information. An integration value associated with the integration window is determined. Next, a determination is made as to whether the integration value is less than a predetermined low amplitude limit. If it is, a comparison is made between a location of a maximum sync frame of a read signal envelope in the integration window and the center of the integration window. The read head is identified as a bi-state head if the location of the maximum sync frame is greater than a predetermined off-center limit relative to the location of the center of the integration window.
摘要:
A method and apparatus are disclosed which allow for compensation of repeatable runout in a disk drive when an actuator arm assembly has a relatively high friction to inertia ratio in a pivot bearing assembly. The compensation uses one of two initial runout coefficients, based on a seek length. If the seek length is shorter than a predetermined distance, a current runout coefficient is used to compensate for repeatable runout which is continuously updated throughout a previous seek operation. If the seek length is greater than the predetermined distance, a transient runout coefficient is used to compensate for repeatable runout which is updated following the initial revolutions of the hard disk.
摘要:
A magnetic storage system includes a disk, a head, an actuator, and a servo controller. The servo controller monitors a value, such as a position error signal (PES) sample value, a predicted PES sample value, and the like, that is based on servo information provided by the head. The servo controller provides a signal to inhibit writing by the head based on a comparison of the monitored value with a threshold, such as a write fault window (WFW), a PES plus Velocity (PPV) threshold, and the like. The servo controller sets the threshold to a first value based on at least one of an on-track track misregistration (TMR) value and a seek settle TMR value. When the servo controller determines that the head is subject to a vibration condition, the servo controller sets the threshold to a second value that is different from the first value.
摘要:
Performing embedded runout correction for a track on a rotational data storage disk includes measuring written-in runout for the track, selecting a number of revolutions in response to the measured written-in runout of the track, calculating embedded correction values for the track for the selected number of revolutions of the rotational data storage disk, and storing the embedded correction values.