Abstract: A disk drive slider positioner (180) includes a frame (184) having a pair of arms (216a, 216b) that cantilever from a base (188). A slider (140) is positioned within frame (184). A pair of slots (224a, 224b) extend down through the frame (184) and also extend along part of the corresponding arm (216a, 216b). Each slot (224a, 224b) includes a corresponding first slot section (228a, 228b) and a wider corresponding second slot section (232a, 232b). A material (240) that is more pliable than the frame (184) preferably occupies the entire length of each first slot section (228a, 228b). Excess first material (240) may overflow into the corresponding wider second slot section (232a, 232b), thereby reducing the potential for excess first material (240) occupying any portion of the space between a leading edge (144) of the slider (140) and the frame (188).

Abstract: An actuator/coil assembly (136) is disclosed where two different bonding operations are used. First, a bobbin (164) is overmolded to a coil (172), and a first overmolded part (176) is overmolded to both the coil (172) and a fan tail (152) of the actuator (140). The overmolding operation defines one or more adhesive receptacles (168) in the bobbin (164) on a perimeter that interfaces with the coil (172), and further defines one or more adhesive receptacles (180) in the first overmolded part (176) on a perimeter that interfaces with the coil (172) and that interfaces with the fan tail (152) of the actuator (140). Adhesive (184) is disposed within these receptacles (168, 180) to increase the stiffness of the actuator/coil assembly (136).

Abstract: Methods and structures for providing patches or updates to embedded ROM firmware simply and inexpensively while avoiding imposition of execution or memory fetch overhead. A patch memory includes locations storing addresses and optional alternate data values. Read/fetch operations addressed to a firmware ROM memory are applied in parallel to the patch memory. All locations of the patch memory may be compared in parallel to the supplied address to determine if a match is found in patch memory. If no match is found, the read/fetch memory cycle completes normally retrieving data from the ROM memory. If a match is found, the alternate data value is applied to the data bus in place of the ROM memory data retrieved. Any ROM location may therefore be patched regardless of whether the location stores instruction or data.

Abstract: A method for preventing electrical overstress from interfering with a magnetic read-write device by identifying one or more characteristic functions of the device that characterize electrical overstress, generating a wave form representative of the electrical overstress by using the one or more characteristic functions and enabling the generated wave form to be combined with a read signal to counteract the electrical overstress. The method can be implemented with a crosstalk cancellation circuit that includes a coupler filter configured to receive signals from the write driver, a differentiator to differentiate the signal, a gain adjust coupled to the coupler filter configured to adjust gain on the received signal, a phase adjust configured to adjust the phase to match the crosstalk, and an inverter coupled to invert the matched signal to enable cancellation of the crosstalk.

Abstract: A decoding system includes a timing loop for use in error recovery mode operations, in which “fast decode” bit values that are used for timing recovery purposes in the normal modes of operation are replaced, at an appropriate iteration in the error recovery mode, with detected bit values from an iterative detector. The replacement occurs after a reread operation in which the timing loop maintains lock.

Abstract: A disk drive has multiple disk surfaces and corresponding heads, each disk surface includes multiple regions, and each head is for recording on and playback of information from a corresponding disk surface. The data track density in a first region on a first disk surface is different than the data track density in a second region on a second disk surface, and the first and second regions are radially similarly situated regions. A method of sequentially accessing data in the first and second regions includes sequentially accessing data tracks in the first region and then sequentially accessing data tracks in the second region.

Abstract: A magnetic recording medium and a magnetic recording apparatus for perpendicular magnetic recording. The recording medium includes a magnetically soft underlayer and a hard magnetic pinning layer having perpendicular anisotropy. The magnetically soft underlayer is substantially free of domain walls.

Abstract: A write head for a media drive suited for perpendicularly recording data in adjacent magnetic recording media, the media having a magnetic recording layer and a soft underlayer (SUL). The write head has a pole tip, a write yoke connected to the pole tip, a write return yoke, a write shield, one or more conductive coils surrounding the write yoke, and one or more side shields disposed in close proximity to the pole tip. The write return yoke connects to the write yoke on one end and the write shield on a different end. The one or more side shields are separated from the pole tip and write shields by a non-magnetic material and therefore are “floating” and not directly coupled to the write shield or pole tip.

Abstract: A disk drive includes a drive housing and a storage disk rotatably coupled to the drive housing. In one embodiment, the storage disk includes a first substrate, a spaced-apart second substrate, a damping layer and a rigid substrate spacer. The first substrate is formed from a first material having a first composition and the second substrate is formed from a second material having a second composition. The damping layer is positioned at least partially between the first substrate and the second substrate. The rigid substrate spacer is positioned at least partially between the first substrate and the second substrate, and is formed from a third material having a third composition that is different from the first composition and the second composition. In one embodiment, the first composition is different than the second composition. The first substrate has a first thickness and the second substrate has a second thickness that can be different than the second thickness.

Abstract: A method and apparatus for sealing a hard disk drive with a low-density gas is provided. A valve body is positioned over an opening in the hard disk drive housing. The valve body is in communication with a source of low-density gas, a vacuum source and the interior of the disk drive. The vacuum source evacuates the internal cavity of the disk drive through the opening. The cavity is then filled with the low-density gas. A reciprocating member then positions a sealing member in the opening to seal the opening and capture the low-density gas within the disk drive.

Abstract: The present invention is directed to a method and apparatus for providing an absolute reference point on a disk surface of a disk drive. A write head associated with the disk surface is used to write spirals of servo information thereon, for example, under control of a servo track writer. The spirals of servo information include standard spirals and special spirals. In one embodiment, the special spirals are shorter than the standard spirals and the special spirals are rotationally non-symmetric. For example, an unequal number of standard spirals are interposed between one pair of adjacent special spirals relative to the number of standard spirals interposed between other pairs of adjacent special spirals. The special spirals may take a variety of other forms to distinguish themselves from standard spirals.

Abstract: An LDPC encoding system produces an encoded block by encoding the data as i data sub-blocks using an LDPC code H1, XOR'ing the H1 sub-block code words to generate a block code word and further encoding the block code word using an LDPC code H2 to produce p parity bits. The encoded block consists of a concatenation of the H1 code words and the p parity bits. To decode the encoded block, the system decodes each H1 sub-block code word and, if all of the H1 sub-block code words converge, the block has been successfully decoded. Otherwise, if one of the H1 code words fails to converge, the system performs an “extended” decoding operation in which the system produces a vector C by XOR'ing the i?1 properly decoded H1 sub-block code words. The system then combines the vector C with the sign values of the failed H1 sub-block code word, appends the parity bits and decodes the result as an H2 code word over the H2 LDPC code.

Abstract: In one example, a method is provided and includes comparing a measured change in spacing between a transducer element and a storage element in response to a fly height control signal with an expected change in spacing for the applied fly height control signal. The method also includes detecting an event condition based on the comparison between the measured change in spacing and the expected change in spacing.

Abstract: A soft decision value output detector includes a plurality of maximum a posteriori (MAP) detectors. The MAP detectors are connected in parallel, and configured to simultaneously generate state metrics for portions of a sampled data sequence, and to generate soft decision values based on the generated state metrics. The MAP detectors may generate soft decision values in a fixed latency manner and without buffering the sampled data sequence for a whole sector of a disk in a disk drive. The MAP detectors may generate soft decision values for portions of the sampled data sequence at least at a rate at which the portions of the sampled data sequence are input to the MAP detectors.

Abstract: A glide head having a portion thereof that is selectively extendable toward the rotating disk by the application of an electrical signal thereto. The extendable portion may be located on a side wing extending from a slider main body. The side wing may include a piezoelectric transducer with a relatively durable contact layer provided on the bottom portion thereof. The slider can be flown relatively close to the rotating media and the transducer can be activated to actuate the contact layer into a closer position relative to the rotating disk. The distance at which physical contact occurs may be measured.

Abstract: In accordance with various embodiments, a rotatable member is mounted to a spindle hub so that initial servo data previously provided to the rotatable member are eccentrically offset with respect to a rotational center of the spindle hub. Compensation vales are determined to characterize said offset, after which final servo data are provided to the rotatable member in relation to the initial servo data and the determined compensation values. The final servo data are nominally concentric with the rotational center of the spindle hub.

Abstract: A magnetic storage system includes a disk, a head, an actuator, and a servo controller. The servo controller monitors a value, such as a position error signal (PES) sample value, a predicted PES sample value, and the like, that is based on servo information provided by the head. The servo controller provides a signal to inhibit writing by the head based on a comparison of the monitored value with a threshold, such as a write fault window (WFW), a PES plus Velocity (PPV) threshold, and the like. The servo controller sets the threshold to a first value based on at least one of an on-track track misregistration (TMR) value and a seek settle TMR value. When the servo controller determines that the head is subject to a vibration condition, the servo controller sets the threshold to a second value that is different from the first value.

Abstract: A disk drive self-servo writes on a storage disk. Servo bursts are self-written along a track using a transducer, a position error signal (PES) indicating repeatable runout due (RRO) for the servo bursts is determined using a reference pattern, an embedded runout correction (ERC) value is calculated based on the PES and stored in a corresponding servo sector, and then the disk drive self-writes other servo bursts.

Abstract: Embodiments of the present invention allow for controlling a microactuator based at least in part on an output of a temperature sensor. Also, embodiments of the present invention allow for adjusting a control of a microactuator so as to compensate for changes in a gain of the microactuator due to changes in temperature.

Abstract: An apparatus is provided for writing reference patterns on a data storage disk of a disk drive. The disk is rotated by a spindle motor. A back EMF sense circuit generates a sequence of zero crossing signals from back EMF sensed on windings of the spindle motor over each revolution of the spindle motor. The sequence of zero crossing signals define a corresponding sequence of zero crossing periods of time between successive zero crossing signals. A Phase Locked Loop (PLL) circuit generates a timing signal in response to comparison of a feedback signal to the zero crossing signals. The PLL circuit also compensates for repeatable variation among the sequence of zero crossing periods over each revolution of the spindle motor so that the timing signal is substantially independent of the repeatable variation among the sequence of zero crossing periods. A recording pattern generator writes reference patterns on the disk in response to the timing signal as the disk is rotated by the spindle motor.