Abstract: An improved and distinctive servo-controller scheme resulting in an overall improvement in PES performance, particularly when applied to hard disk drives employing the invention's TMR reduction mechanisms. The servo-controllers trade off gain in the disk vibration frequency range, in favor of, increased rejection of low frequency disturbances. This leads to the lowest PES statistics, when applied to hard disk drives with the TMR reduction mechanisms of the invention. Improved head gimbal assemblies reducing TMR (Track Mis-Registration) in a hard disk drive are provided. These head gimbal assemblies are as mechanically simple as contemporary head gimbal assemblies, support parallel flying sliders over flat disk surfaces, and reduce TMR induced by disk vibration. They are easier to build, more reliable, and cost less to make, than other known approaches at comparable track densities and rotational rates.

Abstract: A disk holder for an off-line servo-track writer is installed at a driving motor of the off-line servo-track writer in a state in which a plurality of disks for information storage are assembled to the disk holder. The disk holder has a flange for supporting the plurality of disks, a mounting portion to be joined to the driving motor is provided at one side of the flange, and a hub is provided at the other side of the flange. A space into which air flows is formed in the hub, and the plurality of disks and a plurality of spacers for maintaining a gap between the plurality of disks are assembled around the outer circumference of the hub. A plurality of pressing members are installed at the hub to move back and forth in a radial direction of the hub.

Abstract: A spindle motor, which rotates a plurality of data storage disks in a hard disk drive, the spindle motor including: a shaft; an inner hub rotatably installed on an outer periphery of the shaft; and a hub assembly, which includes: an outer hub detachably coupled to an outer periphery of the inner hub, the outer hub shaped such that a plurality of disks and at least one spacer for maintaining an interval between adjacent disks of the plurality of disks can be secured to an outer periphery of the outer hub; and a fastening member coupled to a top portion of the outer hub and fixing the outer hub to the inner hub. The outer hub assembly to which the plurality of disks are secured can be mounted on an off-line servo-track writer, and can also be attached as is to the spindle motor after servo-track writing is completed.

Abstract: The invention applies to servo controllers for at least the voice coil motor of a hard disk drive. Today, many control algorithms require 80 to 90 percent of the sampling period to complete their calculation of the next control, making computation time delay no longer negligible. The invention accommodates the transport delay, such as computation time delay, into the state estimator and into the whole control system. Experimental results using a commercial hard drive, as well as simulation results, show that the invention's method effectively improves the hard disk drive control system stability by increasing the phase margin and gain margin. The invention includes the method of operating the servo-controller, as well as the apparatus implementing that method. The invention also includes hard disk drives containing servo-controllers implementing the method, and program systems residing in accessibly coupled memory to a computer within the servo controller implementing the method.

Abstract: A disk drive having an anti-shock structure is provided. The disk drive includes: a base member; a spindle motor supported by a spindle motor support formed on the base member, the spindle motor rotating a data storage disk; an actuator rotatably coupled to an actuator pivot supported by a pivot support formed on the base member, the actuator moving a read/write head to a position on a recording surface of the disk; and slots formed in the base member around the circumference of each of the spindle motor support and the pivot support, the slots for partially controlling the stiffness of the base member. The slots include a first slot formed on a circumference region of the spindle motor support near the pivot support, and a second slot formed on a circumference region of the pivot support opposite to the spindle motor support. Due to the structure of the disk drive, the spindle motor and the actuator pivot are inclined in the same direction when an external impact is applied.

Abstract: An actuator arm of an actuator assembly includes a 4-bar linkage structure defined by a trapezoidal shaped opening formed between a front end of the actuator arm and a pivot shaft. A first rounded extension portion and a second rounded extension portion are formed at two corners adjacent to the pivot shaft of the opening, respectively, and a third rounded extension portion is formed at two corners adjacent to a front end of the opening, and hinges H1, H2, H3 and H4 are formed at the actuator arm by the first, second and third extension portions. Design factors determining a shape of the opening are optimized to meet the following relations for the structure of the 4-bar linkage: W(cos ??1)+Z(cos ??1)=?x=0, W sin ?+Z sin ?=?y=0.

Abstract: A head stack assembly (HAS) of a hard disk drive (HDD) includes a swing arm, a connection plate integral with a terminal end of the swing arm, a head slider including a magnetic head for reading/writing data from/onto a disk, and a suspension that is attached to the connection plate, supports the head slider, and has characteristics which minimize the degree to which the magnetic head will run off-track due to vibrations induced in the HDD. The suspension includes two connecting parts having upper surfaces at which the suspension is attached to the connection plate. In the HDD, the upper surface of the connecting part positioned closest to the center of the disk center lies in a plane beneath the plane in which the upper surface of the other connecting part lies.

Abstract: The invention includes sliders provided with indented surfaces, reducing the roll center for head gimbal assemblies below the effective thickness of the slider. Head gimbal assemblies built with these sliders may reduce off-track displacements induced by disk vibration. The load beam gimbal may contact the indented surface, creating a slider roll center less than the slider thickness. Alternatively, the sliders may include a slider contact cover interfacing to the load beam forming the gimbal. The slider contact covers may couple with the slider through an indented surface located closer than the slider thickness. These may have a negative slider roll center. The invention includes actuator arms, actuator assemblies, and hard disk drives including these head gimbal assemblies. The invention includes making the invention's sliders, head gimbal assemblies, actuator arms, actuator assemblies, and hard disk drives. The invention includes the products of these processes.

Abstract: Improved head gimbal assemblies reducing TMR (Track Mis-Registration) in a hard disk drive are provided. These head gimbal assemblies are as mechanically simple as contemporary head gimbal assemblies, support parallel flying sliders over flat disk surfaces, and reduce TMR induced by disk vibration. They are easier to build, more reliable, and cost less to make, than other known approaches at comparable track densities and rotational rates. The improved head gimbal assemblies include three sets of mechanisms for moving the slider parallel the disk surface, when the disk surface is flat, and radially moving the slider toward the track, when the disk surface is bent. The first and third mechanisms as well as the second and third mechanisms can be used together in a head gimbal assembly. An improved and distinctive servo-controller scheme resulting in an overall improvement in PES performance, particularly when applied to hard disk drives employing the invention's TMR reduction mechanisms.

Abstract: Provided are a method of calculating repeatable runout (RRO) of a hard disk drive (HDD) in a frequency domain, a method of calculating a compensation value using the RRO calculating method, and recording media used therefore. The method of calculating RRO in a disk with a plurality of tracks includes: calculating first set of frequency coefficients for representing the RRO by analyzing a position error signal (PES), which is sampled in a target track, in a frequency domain while a head follows the target track; and calculating the RRO using the first set of frequency coefficients.

Abstract: Improved head gimbal assemblies reducing TMR (Track Mis-Registration) in a hard disk drive are provided. These head gimbal assemblies are as mechanically simple as contemporary head gimbal assemblies, support parallel flying sliders over flat disk surfaces, and reduce TMR induced by disk vibration. They are easier to build, more reliable, and cost less to make, than other known approaches at comparable track densities and rotational rates. The improved head gimbal assemblies include three sets of mechanisms for moving the slider parallel the disk surface, when the disk surface is flat, and radially moving the slider toward the track, when the disk surface is bent. The first and third mechanisms as well as the second and third mechanisms can be used together in a head gimbal assembly. An improved and distinctive servo-controller scheme resulting in an overall improvement in PES performance, particularly when applied to hard disk drives employing the invention's TMR reduction mechanisms.

Abstract: The invention applies to servo controllers for at least the voice coil motor of a hard disk drive. Today, many control algorithms require 80 to 90 percent of the sampling period to complete their calculation of the next control, making computation time delay no longer negligible. The invention accommodates the transport delay, such as computation time delay, into the state estimator and into the whole control system. Experimental results using a commercial hard drive, as well as simulation results, show that the invention's method effectively improves the hard disk drive control system stability by increasing the phase margin and gain margin. The invention includes the method of operating the servo-controller, as well as the apparatus implementing that method. The invention also includes hard disk drives containing servo-controllers implementing the method, and program systems residing in accessibly coupled memory to a computer within the servo controller implementing the method.

Abstract: A disk holder for an off-line servo-track writer is installed at a driving motor of the off-line servo-track writer in a state in which a plurality of disks for information storage are assembled to the disk holder. The disk holder has a flange for supporting the plurality of disks, a mounting portion to be joined to the driving motor is provided at one side of the flange, and a hub is provided at the other side of the flange. A space into which air flows is formed in the hub, and the plurality of disks and a plurality of spacers for maintaining a gap between the plurality of disks are assembled around the outer circumference of the hub. A plurality of pressing members are installed at the hub to move back and forth in a radial direction of the hub.

Abstract: A head-gimbal assembly of a hard disk drive includes a loadbeam connected to a pivot arm, a slider on which a magnetic head is mounted, an elastic support member having one end coupled to the loadbeam and the other free end portion at which the slider is supported, and a damper provided between the loadbeam and the slider to attenuate vibration transferred between the loadbeam and the slider.

Abstract: An actuator arm of an actuator assembly includes a 4-bar linkage structure defined by a trapezoidal shaped opening formed between a front end of the actuator arm and a pivot shaft. A first rounded extension portion and a second rounded extension portion are formed at two corners adjacent to the pivot shaft of the opening, respectively, and a third rounded extension portion is formed at two corners adjacent to a front end of the opening, and hinges H1, H2, H3 and H4 are formed at the actuator arm by the first, second and third extension portions. Design factors determining a shape of the opening are optimized to meet the following relations for the structure of the 4-bar linkage: W(cos ??1)+Z(cos ??1)=?x=0, W sin ?+Z sin ?=?y=0.

Abstract: A fluid dynamic bearing is constructed to support stably a rotating body to which a non-uniform force is applied, and a hard disk drive (HDD) employing the fluid dynamic bearing is provided. The fluid dynamic bearing includes a journal bearing part supporting a rotary shaft in a radial direction of the rotary shaft, a thrust part formed at one end of the rotary shaft, a thrust bearing part facing the thrust part and supporting the rotary shaft in a longitudinal direction of the rotary shaft, and a plurality of grooves formed on a surface of the thrust bearing part and/or the thrust part. The plurality of grooves include a first groove group including a plurality of grooves having the same shape and arrangement, and a second groove group adjacent to the first groove group and including at least one groove asymmetric with respect to the grooves of the first groove group.

Abstract: A latch system for a hard disk drive and a method of forming the latch system are disclosed. The latch system includes an actuator on which a read/write head is installed, and a latch locking the actuator. The actuator and the latch each has a mass center and a pivot center, and a direction of the mass center of the latch on the basis of the pivot center of the latch is the same as a direction of the mass center of the actuator on the basis of the pivot center of the actuator.

Abstract: The invention applies to servo controllers for at least the voice coil motor of a hard disk drive. Today, many control algorithms require 80 to 90 percent of the sampling period to complete their calculation of the next control, making computation time delay no longer negligible. The invention accommodates the transport delay, such as computation time delay, into the state estimator and into the whole control system. Experimental results using a commercial hard drive, as well as simulation results, show that the invention's method effectively improves the hard disk drive control system stability by increasing the phase margin and gain margin. The invention includes the method of operating the servo-controller, as well as the apparatus implementing that method. The invention also includes hard disk drives containing servo-controllers implementing the method, and program systems residing in accessibly coupled memory to a computer within the servo controller implementing the method.

Abstract: A servo writer that writes servo information onto a disk of a hard disk drive. The servo writer can write servo information onto a disk of a hard disk drive while the disk is within an inner chamber of a housing. The rotating disk creates a flow of fluid within the inner chamber. The disk is rotated during the servo writing process. The density of a fluid medium within the inner chamber is controlled by a medium control system so that the density of the medium is less than the density of air at one atmosphere. Lowering the density decreases the amplitude of vibrational forces created by the flow of fluid. Decreasing the amplitude reduces errors in the servo writing process. The density can be reduced by pulling a vacuum within the inner chamber. The density can also be reduced by filling the inner chamber with a gas such as helium that has a lower density than air.

Abstract: The invention applies to servo controllers for at least the voice coil motor of a hard disk drive. Today, many control algorithms require 80 to 90 percent of the sampling period to complete their calculation of the next control, making computation time delay no longer negligible. The invention accommodates the transport delay, such as computation time delay, into the state estimator and into the whole control system. Experimental results using a commercial hard drive, as well as simulation results, show that the invention's method effectively improves the hard disk drive control system stability by increasing the phase margin and gain margin. The invention includes the method of operating the servo-controller, as well as the apparatus implementing that method. The invention also includes hard disk drives containing servo-controllers implementing the method, and program systems residing in accessibly coupled memory to a computer within the servo controller implementing the method.