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: 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 hard disk drive that has a locking actuator which can engage and lock a disk and spindle motor of the drive. The locking actuator may have a shape memory alloy element that causes a plunger to engage and lock a disk(s) when power is terminated to the drive. In the locked position the actuator can minimize the impact of shock and vibration loads on the spindle motor, particularly when the hard disk drive is shipped and transported. The shape memory alloy element is heated when the hard disk drive receives power. The heated shape memory alloy element disengages the plunger from the disk and allows for operation of the disk drive.

Abstract: A hard disk drive that has a reaction mass and a transducer that can be used to move and/or sense the acceleration of an actuator arm of the drive. The transducer is coupled to a disk controller that can provide output signals which induce a movement of the reaction mass. Movement of the reaction mass will cause a responsive movement of a head(s) coupled to the actuator arm. The transducer can also provide input signals to the controller that correspond to an acceleration of the actuator arm. The acceleration signal can provide force feedback for a servo system of the drive.

Abstract: Aerodynamic forces contribute to disk and actuator vibration leading to track positioning errors in storage devices such as hard disk drives. The invention provides a variety of dampening mechanisms and a method of dampening to alleviate these problems in single disk storage devices. This includes disk drives of at most 13 millimeters in height.

Abstract: Aerodynamic forces contribute to disk and actuator vibration leading to track positioning errors in storage devices such as hard disk drives. The invention provides a variety of dampening mechanisms and a method of dampening to alleviate these problems.

Abstract: A hard disk drive which has a housing that can attenuate noise. The housing may include a first layer that is attached to a second layer and a third layer located between the first and second layers. The layers may be designed to create a transfer function that attenuates, or rolls off, acoustic noise within a range of frequencies.

Abstract: A disk drive housing that can attenuate noise. The housing may include a first layer that is attached to a second layer, and a gap located between the first and second layers. The layers and gap may be configured to attenuate acoustic energy within a relatively broad frequency range.

Abstract: An actuator that can vary the gram load of a suspension arm of a hard disk drive. The actuator may be a shape memory alloy, piezoelectric transducer, or other means for deflecting and changing the gram load of a suspension arm of an actuator arm assembly. When the disk drive is not operating the gram load may be set to a high value that will prevent head slapping. The gram load of the suspension arm may be varied by the actuator to reduce the gram load when the disk drive is operating.

Abstract: A hard disk drive that includes a wave stringer. The wave stringer can attenuate energy which propagates through a base plate of the disk drive. The wave stringer may be designed by initially analyzing propagation patterns of both acoustic and shock waves applied to the drive. The wave stringer is then designed, constructed and assembled to the disk drive to attenuate critical frequencies at weak points of the disk drive. The wave stringer may have a plurality of ribs designed to vary the mechanical impedance of the drive to attenuate the propagated energy.

Abstract: A method of and an apparatus for controlling noise generated in a confined space, being capable of reducing a radiating sound pressure generated from a main noise source to that of an optimal state. The method includes the steps of measuring the radiating sound pressure generated from the noise source, and generating, from an additional sound source, a radiating sound pressure having the same magnitude as the radiating sound pressure generated from the noise source while having a phase 180.degree.-shifted from that of the noise source's radiating sound pressure so that the radiating sound pressures can offset each other when they are mixed.