Abstract: A method is disclosed for determining repeatable runout (RRO) cancellation values in a disk drive having a head disk assembly (HDA) and a sampled servo controller. The HDA includes a disk having distributed position information in servo wedges, a rotary actuator carrying a head that periodically reads the position information, and a voice coil motor circuit that responds to a control effort signal. The servo controller periodically adjusts the control effort signal during a track-following operation. In the method, the position information related to a predetermined track is read during track following for more than one disk rotation. The position information is averaged for each servo wedge obtained during the disk rotations. The averaged servo position values are filtered with a filter for compensating effects of the sampled servo controller, which tend to distort the averaged servo position values, to generate the RRO cancellation values for the predetermined track.

Abstract: According to the present invention, there is provided a disk drive that includes a housing including a body portion and an airflow suppressor portion extending from the body portion. The disk drive includes a disk that includes an inner disk edge, an outer disk edge and a disk surface. The disk drive includes a head stack assembly rotatably coupled to the body portion. The head stack assembly includes an actuator arm including a first arm surface disposed adjacent the disk surface and an opposing second arm surface. The disk drive includes upstream and downstream regions. The airflow suppressor portion is radially disposed substantially between the inner and outer disk edges within the upstream region and extends entirely from the housing body portion beyond the second arm surface towards the disk surface for modifying disk rotation induced airflow upon the head stack assembly.

Abstract: A disk drive is disclosed comprising a spindle motor comprising a plurality of windings for rotating a disk. The spindle motor is rotated by commutating the windings over a plurality of commutation states, wherein audible noise generated by the disk drive is reduced by phase modulating the commutation interval. Further audible noise reduction is achieved by modulating a current applied to the windings which substantially reduces discontinuities in the torque output of the spindle motor caused by phase modulation of the commutation intervals.

Abstract: A disk drive is disclosed which executes a rotational position optimization (RPO) algorithm to select a next command to execute from a command queue relative to an estimated access time. If an external vibration is detected, the RPO algorithm increases at least one of an estimated seek latency, an estimated settle latency, and an estimated rotational latency for each command in the command queue.

Abstract: A disk drive comprising a first seek operating mode to move the actuator over a seek distance D in a seek time T1, using a first seek profile for minimizing T1, wherein for a first repetitive series of seeks over distance D a servo control system would require a delay time TD between seeks to control temperature rise in a VCM. A second seek operating mode to move the actuator over the seek distance D in a second seek time T2 using a second seek profile for limiting the temperature rise in the VCM, wherein for a second repetitive series of seeks over the seek distance D, a time average TAVG of the T2 seek times is substantially less than T1+TD.

Abstract: A disk drive with a shock event logger that records information about a shock event as determined by a shock detection system. The shock detection system analyzes signals that result from movement of part of the disk drive and determines if the movement is due to a shock. Information about the shock event is recorded by the shock event logger to a non-volatile memory. In one embodiment, the shock detection system is a position error signal processor that detects shocks based on deviation of a transducer from its reference position, or based on time elapsed during settling of the deviated transducer. In one embodiment, the shock event logger records information about the shock event sequentially. In another embodiment, the shock event logger records the shock event information in the form of a histogram. Logged shock event information improves the manner in which the disk drive is diagnosed and serviced.

Abstract: Disclosed is a control system for processing sampled servo data in a disk drive. The control system includes a microprocessor and a servo processing accelerator circuit for performing operations on the sampled servo data while the microprocessor is executing firmware code. The accelerator circuit supports the use of a higher servo bandwidth thus allowing a higher track density resulting a greater storage capacity for the disk drive. Also, the accelerator circuit relieves the microprocessor of the ordinary servo processing function. Thus, the microprocessor's limited processing capacity to be directed to other controller and interface functions of the disk drive. Only under unusual conditions, such as a write-unsafe (WUS) limit exception, does the microprocessor need to direct processing capacity to the servo processing function. Further, the accelerator circuit may be a decreased response time after reading the servo data from the disk.

Abstract: A disk drive is disclosed comprising a first disk surface and a second disk surface, wherein a first head is actuated radially over the first disk surface and a second head is actuated radially over the second disk surface. Each disk surface comprises a plurality of tracks, wherein each track comprises a plurality of data sectors for storing user data and N embedded servo sectors for storing servo data. The N embedded servo sectors on the tracks on the first disk surface are recorded at a physical angular offset from the N embedded servo sectors on the tracks on the second disk surface. While accessing a track on the first disk surface through the first head, the servo data on the first disk surface is read through the first head and the servo data on the second disk surface is read through the second head, thereby increasing the servo sample rate.

Abstract: A disk drive includes a disk, a voltage supply, a head stack assembly and a switching circuit. The head stack may include a coil portion that includes a coil assembly having first and second wound coils. The switching circuit is electrically coupled to the voltage supply and to the coil assembly, and is configured to selectively switch the first and second wound coils between a first configuration and a second different configuration in which the first wound coil is electrically in parallel with the second wound coil.

Abstract: A method of reducing rotational vibration effects in a disk drive by sensing vibration in a sensor and generating corresponding sensor data; deriving a statistical sensor (SS) value based on the sensor data; deriving a statistical position error signal (SPES) value from servo sectors read by the head; comparing the SS value to a SS-threshold value; comparing SPES value to a SPES-threshold value; and generating a feed-forward command effort signal for reducing rotational vibration effects if the SS value exceeds the SS-threshold value and if SPES value exceeds the SPES-threshold value.

Abstract: Reduced bit number wedge identification techniques for use within a rotating media storage device (RMSD) are disclosed. The RMSD includes a disk having a circumferential track that includes a plurality of embedded servo wedges utilized in track following. A substantial majority of the plurality of wedges include a reduced bit wedge ID field that does not have a sufficient number of bits to uniquely identify the wedge within the track. A combined wedge ID code is formed from reading at least first and second reduced bit wedge ID numbers from first and second wedges, respectively, which is used to uniquely identifying a wedge.

Abstract: A mobile host device configured to draw electrical energy from an energy storage device includes a disk drive. The disk drive includes a disk drive enclosure including a base, a spindle motor attached to the base, a disk positioned on the spindle motor, a generator and a charging circuit. The generator may be coupled to the disk drive enclosure and/or the mobile host device and generates electrical energy from the motion of the mobile host device and/or disk drive. The charging circuit is configured to charge the energy storage device using the electrical energy generated by the generator.

Abstract: The present invention may be embodied in a method for adjusting a servo sector detection delay time between detection windows in a disk drive. The disk drive includes a magnetic disk with a spiral track having contiguous storage segments. Each storage segment has a servo sector and a predetermined number of uniformly-sized data sectors. The storage segments are written at a relatively constant linear density along the spiral track. In the method, the magnetic disk is rotated at a constant angular velocity. A servo sector is detected. An adjustable delay time is provided for opening a window to detect a next servo sector. The window is opened after the adjustable delay time expires. A next servo sector is detected in the window. A time between the servo sector detections is measured and the adjustable delay time is adjusted based on the measured time.

Abstract: Disclosed is a disk drive using an accelerometer to sense linear vibration and cancel its effects with an adaptive algorithm during track following. The accelerometer is oriented to detect acceleration associated with torque that tends to cause the actuator to move off-track notwithstanding the efforts of the servo control system. The accelerometer's filtered output is used to modify the control effort. The disk drive uses the position error signal to adaptively filter the accelerometer's output in an effort to mathematically converge on a set of optimal filter coefficients and thereby reduce the effect of vibration that may otherwise impose a torque on the actuator.

Abstract: A method of erasing a disk by applying a direct current to a transducer while the transducer is moved in a selected manner relative to the rotating disk. The rotating disk in conjunction with the erasing transducer moving in a first direction in a substantially continuous and smooth manner yields a helical shaped erased path on the disk. Such helical erasure of the disk is faster than conventional erasure method that erases the disk by erasing in concentric circular paths. To erase in circular paths, the transducer needs to be positioned on that circular path, and positioning of the transducer involves a repositioning time that can be significant. The helical erasure method substantially eliminates the repositioning time since the path of the transducer is substantially continuous and smooth. The reduction in erasure time by use of helical erasure method is substantial when compared to the total erasure time.

Abstract: A method of manufacturing a disk drive and a disk drive where the width of the read element and the width of the write element are both measured at servo-writing time and the track pitch of the disk drive is set on the basis of those measurements. Disk drives with superior head width combinations are servo-written with a narrower track pitch in order to have a higher storage capacity. Disk drives with inferior head width combinations are detected before servo-writing so that the disk drive may be servo-written with wider track pitch rather than with a nominal track pitch that results in a subsequent drive failure during initial burn-in (IBI). The heads are used more efficiently in that heads that are more capable are used to their ability and less capable heads that would otherwise be disposed of are used at all.

Abstract: A method of manufacturing disk drives that are subject to disk pack imbalance includes steps of measuring the disk pack imbalance of each drive and assigning each of the drives to one of a predetermined plurality of categories, depending upon the measured disk pack imbalance. The measured imbalance of the disk drives assigned to fewer than the predetermined plurality of categories may then be reduced. Each category may be associated with one or more customers and the drives assigned to each category may be shipped to the associated customer(s).

Abstract: A method for reducing written-in runout of a disk drive writes a plurality of servo tracks onto a magnetic-storage portion of a disk that comprises a first radial band proximate the outer circumference of the disk, and a second radial band between the first radial band and the inner circumference of the disk. A first plurality of servo tracks is written to the storage medium in the first radial band at a first servo-writing spin rate. A second plurality of servo tracks is written to the storage medium in the second radial band at a second servo-writing spin rate that is different from the first servo-writing spin rate.

Abstract: The invention may be embodied in a method for operating a disk drive in a mobile device to optimize power usage. The mobile device may be a hand held computing device such as a personal digital assistant (PDA) or a mobile terminal such as a cellular telephone. Immediately after responding to a disk access command, the disk drive is in first operating mode that consumes a relatively high level of power and may transition to a second operating mode that consumes a relatively low level of power. A transition from the second operating mode to the first operating mode consumes a transition quantity of power. A predictive technique tracks a user's usage pattern and adapts an operating mode transition time based on the usage pattern.

Abstract: A computer program embodied on a computer readable storage medium is disclosed for dependently adjusting at least three operating levels of a disk drive by dependently adjusting a plurality of disk drive parameters. The computer program receives control input from one or more sources, such as an end user, an environmental sensor, or the disk drive, wherein the control input for adjusting at least three operating levels of the disk drive in a dependent manner. In response to the control input, the computer program adjusts a plurality of parameter settings in the disk drive in a dependent manner. In one embodiment, the operating levels dependently adjusted by the control input comprise a performance level, a capacity level and a robustness level.