Abstract: An apparatus and method of predicting functional capability of a data storage device having a plurality of information tracks, comprising performing a DC erase on three adjacent information tracks, writing a predetermined bit pattern on a middle track of the three adjacent information tracks, providing a first signal from the bit pattern to a variable gain amplifier to generate a first value of the variable gain amplifier, performing DC erases on the information tracks adjacent the middle track, reading the bit pattern from the middle track to provide a second signal to the variable gain amplifier to generate a second value of the variable gain amplifier, and operating on the first and second values of the variable gain amplifier to provide a track mis-registration value for use with a predetermined threshold value to determine the functional capability of the data storage device.

Abstract: A disc drive includes a base and a disc rotatably attached to the base. The disc has an inner diameter and an outer diameter and a plurality of tracks. Information is written on the plurality of tracks. The plurality of tracks are written at a variable track pitch. The tracks positioned near the outer diameter are wider in pitch than the tracks positioned near the inner diameter. The plurality of tracks further include a first group of tracks written at a first track pitch, and a second group of tracks written at a second track pitch. The track pitch of each of the first group and the second group of tracks is selected such that the percentage of track misregistration for each group will be substantially the same. This method provides a means to increase storage capacity for a predetermined track misregistration budget.

Abstract: A disc drive includes an information storage disc and an actuator assembly. A retraction voltage and a retraction time interval are calculated based on the location of a transducer over a surface of the information storage disc. The retraction voltage is applied for the retraction time interval such that the actuator assembly reaches the park position at a predetermined velocity. A brake time interval is calculated when the disc drive is operating in seek mode while power to the disc drive is interrupted. A brake is applied for the brake time interval to halt movement of the actuator assembly before the retraction voltage is applied. The values of retraction voltage, retraction time interval and brake time interval are continually updated in data tables. The values are retrieved when power to the disc drive is unexpectedly interrupted such that the actuator assembly reaches the park position at the predetermined velocity.

Abstract: A method for writing servo patterns on at least one disc in a disc drive that has a first set of tracks and a second set of tracks on a major surface of the disc includes stepping between the tracks of the first set of tracks at a first constant angle, and stepping between the tracks of the second set of tracks at a second constant angle. Stepping between tracks in the first group or the second group includes selecting two adjacent tracks from either the first group of tracks or the second group of tracks, and determining the angle through which an actuator assembly must be rotated between the two adjacent tracks selected to produce a selected track pitch. The method produces a disc for a disc drive with a first set of tracks, and a second set of tracks in which the track pitch varies across the set of tracks.

Abstract: An improved actuator assembly with an out-of-plane voice coil and method of making thereof. The actuator assembly has two substantially planar arms for supporting both read/write devices and the out-of-plane voice coil. The arms are severally formed by stamping processes, and assembled with a pivot mechanism therebetween. The voice coil is affixed to both arms.

Abstract: Disclosed are methods and systems for more accurately measuring the performance of a data-storage device by compensating for the repeatable runout (RRO) errors that are written-in to tracks during manufacture. During the manufacturing process, the disc is divided into zones containing a number of tracks. A representative RRO, known as the coherent RRO (CRRO), in each zone is obtained by sampling the position error signal (PES) of some or all of the tracks in each zone and, in one embodiment, using the average PES for the zone as the CRRO. The CRRO, which is the majority of the PES, is removed from the PES to create a corrected error signal (CES). The CES is used to evaluate the performance of the data-storage device rather than the PES. Because the CRRO does not affect the performance of the data-storage device, removing it results in a more accurate measurement.

Abstract: An actuator having a relatively low mass for supporting flexible head suspension assemblies to read data from or write data to discs. The actuator includes an actuator body adapted to rotationally coupled to a base chassis of the disc drive and a yoke assembly including yoke arms extending from the actuator body. The actuator includes at least one rigid actuator arm rigidly supporting the flexible head suspension assemblies. The rigid actuator arm includes multiple arm plates supported in spaced relation to provide a thickness of the actuator arm for lateral stiffness.

Abstract: Method and apparatus for protecting a data storage device from fluid-borne contaminants. The device includes a housing in which a rotatable disc is supported, the disc having a data recording surface and an outermost perimeter. A filter assembly includes a first filter adjacent to the data recording surface and a second filter disposed beyond the outermost perimeter of the disc. During disc rotation, fluidic currents are generated and impinge a leading edge guide surface of the first filter. A first portion of the currents passes into a gap between the first filter and the data recording surface. A second portion of the currents passes along the leading edge guide surface to the second filter. The first filter is preferably characterized as a chemical adsorbent filter which adsorbs vapor phase (gaseous) contaminants, and the second filter is preferably characterized as a pass-through recirculation filter which captures particulate contaminants.

Abstract: Method and apparatus for protecting a data storage device from fluid-borne contaminants. The device includes a housing in which a rotatable disc is supported, the disc having a data recording surface and an outermost perimeter. A filter assembly includes a first filter adjacent to the data recording surface and a second filter disposed beyond the outermost perimeter of the disc. During disc rotation, fluidic currents are generated and impinge a leading edge guide surface of the first filter. A first portion of the currents passes into a gap between the first filter and the data recording surface. A second portion of the currents passes along the leading edge guide surface to the second filter. The first filter is preferably characterized as a chemical adsorbent filter which adsorbs vapor phase (gaseous) contaminants, and the second filter is preferably characterized as a pass-through recirculation filter which captures particulate contaminants.

Abstract: Steps for isolating and correcting total written-in repeatable run-out error written into servo sectors of a disc drive include, determining a total repeatable run-out error value for each servo sector, isolating a repeatable error value component of the total written-in repeatable run-out error value for each servo sector, removing the repeatable error value component from total written-in repeatable run-out error value to provide a non-repeatable error value component of the total written-in repeatable run-out error value for each servo sector, providing both the repeatable and non-repeatable error value components to a processor for generation of compensation signals, and applying the compensation signals into a servo control circuit of control loop of the disc drive using compensation circuits to compensate for each component of the total written-in repeatable run-out error.

Abstract: A disc drive includes a housing enclosing a spindle motor that is able to spin a disc. A filter within the housing is positioned so that a filter stream of moving gas created by a spinning motion of the disc flows through the filter. Additionally, a flow divider is secured to a portion of the housing and positioned within the filter stream upstream of the filter, splitting the filter stream into a first branch and a second branch. Both branches flow through the filter.

Abstract: The present invention relates to an air guide for use in a disc drive such that air flow can be redirected to improve the efficiency of a filter located within the disc drive. Embodiments of the present invention provide for an air guide having air guide surfaces that, in conjunction with sides of the disc drive housing, are configured to channel air flow off a spinning disc, through a filter, and back into the mainstream air flow. The air guide may be formed as an integral unit with either the inner major surface of the cover or of the baseplate, or both, such that the air guide may extend over part of the disc surface and provide an effective channel for air flow without the need for additional assembly processes during manufacture.

Abstract: The disc drive housing encloses a spindle motor carrying a disc having a data surface. An actuator assembly includes an actuator arm carrying a head. The housing includes a first surface portion adjacent to the data surface of the disc. The housing also includes a plurality of surface portions that define a recess, which allows the actuator arm to move over the data surface of the disc. The plurality of surface portions include a sloped surface portion sloping away from the data surface and preventing wind generated by the disc rotating about an axis from separating from the sloped surface portion. Alternatively, a disc drive includes a housing that defines a recess. The housing encloses a disc mounted on a spindle motor that rotates the disc about an axis and thereby generates wind within the housing. An upstream surface portion and a downstream surface portion of the housing both face toward a data surface of the disc.

Abstract: An apparatus and method of indirectly measuring half frequency whirl in a spindle motor having a rotor adapted to rotate a disc having a track which is followed by a transducer head that is actuated by a control system is provided. Vibration signals produced at the transducer head while the transducer head follows the track are detected. The half frequency whirl is determined as a function of the detected vibration signals.

Abstract: A disc clamp made from a shape memory alloy is configured for tight fit between an upper ledge of a spindle hub and the upper surface of a disc when the disc clamp is in an austenitic phase. In a martensitic phase, the disc clamp is configured for easy assembly over the spindle hub. The disc of the present invention provides for uniform distribution of clamping forces on the disc, and avoids the need for threaded holes in the spindle hub.

Abstract: A method of preventing a write operation to a disc in a disc drive during a shock event without the use of a separate shock sensor comprises steps of monitoring an actuator voice coil motor (VCM) control plant output signal, generating an actuator voice coil motor (VCM) plant model module output signal, comparing the VCM plant model module output signal to the VCM control plant module output signal to produce a difference signal, and triggering a write protect gate if the difference signal exceeds a predetermined threshold value.

Abstract: Apparatus and method for adjusting an actuator mechanical response characteristic in a data handling system, such as a disc drive. An actuator rotates about a pivot system to move a read/write head adjacent a recording surface, the pivot system comprising a stationary shaft and a bearing asesmbly comprising a stationary inner race coupled to the shaft and a rotatable outer race coupled to the actuator. A fastener is provided to engage the shaft and apply an initial amount of axially directed force on the inner race. A broad spectrum excitation is applied to the actuator and a mechanical response characteristic of the actuator is measured. The fastener is repetitively adjusted to increase the amount of axially directed force until the measured mechanical response characteristic of the actuator reaches a desired level.

Abstract: An apparatus and method of predicting functional capability of a data storage device having a plurality of information tracks, comprising performing a DC erase on three adjacent information tracks, writing a predetermined bit pattern on a middle track of the three adjacent information tracks, providing a first signal from the bit pattern to a variable gain amplifier to generate a first value of the variable gain amplifier, performing DC erases on the information tracks adjacent the middle track, reading the bit pattern from the middle track to provide a second signal to the variable gain amplifier to generate a second value of the variable gain amplifier, and operating on the first and second values of the variable gain amplifier to provide a track mis-registration value for use with a predetermined threshold value to determine the functional capability of the data storage device.

Abstract: An HDA includes a base, a disc stack coupled to a spindle rotatably attached to the base by a spindle shaft and spindle bearing. An actuator assembly is pivotally attached to the base at a pivot shaft. Attached to one end of the actuator assembly proximal the disc stack is one or more transducers for reading/writing information from/to the discs. A servo writer includes a controller for moving the actuator during the servo writing process. The controller moves the servo writer at the cage frequency of the spindle bearing to lessen the relative motion between the transducer head and the disc as the servo information is written to the disc. The controller also may be programmed to move the transducer at both the spindle rotation frequency and the cage frequency of the spindle bearing to lessen the relative motion between the transducer and the disc during the servo writing process.

Abstract: Disclosed is a method and apparatus for determining the dynamic characteristics of a desired component of an actuator assembly. Further, said method and apparatus are capable of determining the dynamic characteristics independent of any drive servo electronics. The system and method can also be used to determine other operating parameters such as rotational inertia. This information is useful for design verification, quality assurance and failure analysis.