Abstract: A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of servo tracks defined by a plurality of servo sectors, wherein each servo sector comprises a plurality of servo bursts, and each servo burst comprises a predetermined phase. After positioning the head over one of the servo tracks, a servo burst in one of the servo sectors is read to generate a read signal, and a sine and cosine component are extracted from the read signal. At least one of the sine and cosine components is rotated by an angle based on a radial location of the head. A position error signal for the head is generated in response to the rotated component.

Abstract: A disk drive is disclosed comprising a head actuated over a disk, the disk including a plurality of servo sectors wherein each servo sector comprises at least one servo burst. A read signal emanating from the head is sampled while reading a servo burst in a servo sector to generate a plurality of sample values. A quality metric is generated in response to a plurality of sample values of a servo sub-burst representing part of the servo burst. When the quality metric does not exceed a threshold, the servo sub-burst sample values are excluded when generating a position error signal (PES) representing a position of the head over the disk. When the quality metric exceeds the threshold, the servo sub-burst sample values are included when generating the PES. The head is then positioned over the disk in response to the PES.

Abstract: A disk drive is disclosed comprising a disk having a plurality of data tracks defined by a plurality of servo sectors, wherein each servo sector comprises a Gray coded address representing at least part of a track address. The disk drive further comprises a head actuated over the disk for detecting a first Gray coded address in a first servo sector. A second Gray coded address is generated in response to the first Gray coded address. The first Gray coded address is decoded into a first binary address, and the second Gray coded address is decoded into a second binary address. One of the first and second binary addresses closest to a target address is selected, and the head is positioned in response to the selected binary address.

Abstract: A disk drive is disclosed comprising a disk having servo data defining a plurality of servo tracks. The servo data comprises a preamble, and a plurality of slanted line servo bursts recorded at a tilt angle with respect to the preamble. The slanted line servo bursts comprises a first plurality of slanted line servo bursts and a second plurality of slanted line servo bursts, wherein the second plurality of slanted line servo bursts are offset radially from the first plurality of slanted line servo bursts. A position error signal (PES) is generated in response to a phase difference when reading the preamble and the slanted line servo bursts.

Abstract: A disk drive is disclosed comprising a disk having servo data defining a plurality of servo tracks. The servo data comprises a preamble, and a plurality of slanted line servo bursts recorded at a tilt angle with respect to the preamble. At least one of the slanted line servo bursts comprises a first polarity along a first segment of the slanted line and a second polarity along a second segment of the slanted line. A position error signal (PES) is generated in response to a phase difference when reading the preamble and the slanted line servo bursts.

Abstract: A system and method for efficiently identifying track squeeze errors (TSEs) of a disk of a disk drive during a testing process for the disk drive is disclosed. The method includes reading servo bursts from a track of the disk, utilizing a modeled scan variable, and determining a gain comprising a ratio of a first matrix A and a second matrix B. TSEs associated with the SWEs of the servo bursts are determined for the track. The TSEs are determined as a product of the gain and a measured scan variable wherein the measured scan variable is calculated as being the difference between a measured scan value and an estimated nominal scan value.

Abstract: A disk drive that compensates for written-in track squeeze errors (TSEs) during track following is disclosed. The disk drive may be used to compensate for TSEs when determining the position error signal (PES) by implementing operations that include: determining a track squeeze value for a servo sector based upon read servo bursts; determining a PES value for the servo sector based upon read servo bursts; estimating a Squeeze Correction Coefficient (SCC) to account for track squeeze induced PES sensing gain variation associated with the servo sector based upon the PES value and the track squeeze value; calculating a squeeze corrected PES value based upon the SCC and the PES value; and utilizing the squeeze corrected PES value in servo control.

Abstract: A disk drive is disclosed including a disk having a plurality of tracks, wherein each track comprises a plurality of servo sectors. The disk drive further comprises a head having a read element offset from a write element by a reader/writer offset. The read element is positioned over a first track and the write element is positioned over a second track. A first servo control signal is generated for servoing the head in response to the servo sectors in the first track, and first wedge repeatable runout (RRO) data is written to the second track along a substantially sinusoidal path corresponding to the reader/writer offset, wherein the first wedge RRO data are for writing data to a third track.

Abstract: A disk drive is disclosed comprising a plurality of servo sectors that define a plurality of tracks, and a head comprising a read element radially offset from a write element. The read element is positioned over a first track, and the first track is read to generate first read wedge repeatable runout (WRRO) values. A first seek operation of the head positions the read element over a second track, and the second track is read to generate first write WRRO values. The first write WRRO values are used to write the first read WRRO values to the first track. A second seek operation of the head positions the read element over a third track, and the third track is read to generate second write WRRO values. The second write WRRO values are used to write the first write WRRO values to the second track.

Abstract: A disk drive is disclosed comprising a disk having a plurality of tracks, wherein each track comprises a plurality of data sectors and a plurality of servo sectors. The disk drive further comprises a head actuated over the disk, the head comprising a read element radially offset from a write element by a reader/writer offset. In order to rewrite a marginal servo sector detected in a target track, control circuitry within the disk drive relocates user data recorded in a first data sector of a near adjacent track to a staging memory. Servo data is written over the first data sector, and the read element is used to read the servo data written over the first data sector to actuate the head to rewrite the marginal servo sector of the target track. The user data stored in the staging memory is then rewritten to the first data sector.

Abstract: A clock tracking circuit and method uses a clock compensation signal to compensate for timing marks on a media disk. The clock compensation signal may compensate for at least one of improper clock track closure and written-in jitter of the timing marks used to produce the measured clock signal. The clock compensation signal may be used to control a controllable oscillator used to generate the clock signal that thereby provides a compensated clock signal.

Abstract: A clock tracking circuit and method uses a clock compensation signal to compensate for timing marks on a media disk. The clock compensation signal may compensate for at least one of improper clock track closure and written-in jitter of the timing marks used to produce the measured clock signal. The clock compensation signal may be used to control a controllable oscillator used to generate the clock signal that thereby provides a compensated clock signal.

Abstract: A method for computing position error signal information of a transducer in a data storage system provides for different readback signals between adjacent tracks. The method involves a computation to obtain coarse position information from the servo bursts signals for track seeking and a computation to obtain a position indicator from the user data sector for more precise track following within the user data sector.

Abstract: The present invention provides for a flexural pivot that can be fitted within a cavity of an actuator. The pivot includes a first member that can be coupled to the wall defining the cavity and a second member that can be mounted to the disc drive housing component of the disc drive. At least two leaves join external surfaces of the first member to the second member. The present invention offers a flexural pivot that can be easily incorporated with rotary actuators traditionally designed for use with a ball bearing pivot cartridge. In addition, it avoids the difficulties encountered by conventional designs when trying to assemble intersecting flat springs within a cylindrical sleeve. Furthermore, in comparison with conventional flexural pivots that are located outside the actuator body, the present invention provides a compact pivot that can be mounted substantially in a cavity of the actuator body such that the center of rotation of the actuator is located nearer the center of mass.

Abstract: The present invention relates to controlling an actuator for positioning a read/write head in storage devices such as disk drives. More specifically, the invention relates to using a sensor to detect the disk vibration amplitude perpendicular to the disk surface, and using feed forward control to cancel or counteract the tendency of the read/write head to deviate off-track due to disk vibration. Various approaches are proposed to detect the disk vertical vibration.

Abstract: A method for computing position error signal information of a transducer in a data storage system provides for different readback signals between adjacent tracks. The method involves a computation to obtain coarse position information from the servo bursts signals for track seeking and a computation to obtain a position indicator from the user data sector for more precise track following within the user data sector.

Abstract: A microactuator (30) is provided for positioning a read/write head relative to a mounting region of a head suspension assembly of a magnetic disk drive. The microactuator (30) comprises a substantially C-shaped member (32) having a first end (34) and a second end (38) defining an air gap (42) therebetween. In one embodiment the member (32) is a piezoelectric bimorph expander; in another embodiment the member is a ferromagnetic core. Under an applied electric or magnetic field as appropriate, the size of the air gap (42) may be altered and, because the member (32) is resilient, the original air gap may be restored on removing the applied field. The microactuator may be mounted on the load beam of the head suspension assembly, or between the load beam and head slider supporting the read/write head.

Abstract: The present invention relates to controlling an actuator for positioning a read/write head in storage devices such as disk drives. More specifically, the invention relates to using a sensor to detect the disk vibration amplitude perpendicular to the disk surface, and using feed forward control to cancel or counteract the tendency of the read/write head to deviate off-track due to disk vibration. Various approaches are proposed to detect the disk vertical vibration.

Abstract: A micro actuator driven load beam mechanism for use in a head suspension assembly is disclosed. The mechanism includes a load beam including a proximal end portion and a distal end portion, a hinge portion connecting the proximal and distal end portions of the load beam for permitting relative movement therebetween, and a piezoelectric beam connecting the proximal and distal end portions, the piezoelectric beam being selectively energizable to effect relative movement between the proximal and distal end portions. The load beam includes a pocket for holding at least one end of the piezoelectric beam. The piezoelectric beam and the pocket may be inclined relative to a hinge plane to control the load beam twist and minimize the altitude variations of the beam tip.

Abstract: A microactuator (30) is provided for positioning a read/write head relative to a mounting region of a head suspension assembly of a magnetic disk drive. The microactuator (30) comprises a substantially C-shaped member (32) having a first end (34) and a second end (38) defining an air gap (42) therebetween. In one embodiment the member (32) is a piezoelectric bimorph expander; in another embodiment the member is a ferromagnetic core. Under an applied electric or magnetic field as appropriate, the size of the air gap (42) may be altered and, because the member (32) is resilient, the original air gap may be restored on removing the applied field. The microactuator may be mounted on the load beam of the head suspension assembly, or between the load beam and head slider supporting the read/write head.