Abstract: A shield for a read element of a magnetic recording head is disclosed. The shield includes a first and a second triangular shaped closure magnetic domains positioned approximate a top surface of the shield such that a first surface of each of the first and second magnetic domains are formed by a portion of a first side of the shield and a second side of the shield, respectively. The shield also includes a third and a fourth triangular shaped closure magnetic domains positioned approximate the bottom surface of the shield. A first surface of the third and fourth magnetic domains are formed by a portion of the first side and the second side of the shield, respectively. A first magnetic domain wall is positioned between the first and second triangular shaped closure magnetic domains, while a second magnetic domain wall is positioned between the third and fourth triangular shaped closure magnetic domains.

Abstract: A detector is used in detecting data encoded in a read signal received from a storage channel. The detector includes a Viterbi detector having a time-invariant structure configured to detect the data encoded according to a code having time varying constraints.

Abstract: Curvilinear servo sector patterns are produced on a master media by determining a series of offsets between a radially aligned reference and the desired curvilinear servo sector and expressing each offset as a delay that can be expressed in settings for controlling a master writer. Incorporation of the delay into the master writer allows a curvilinear servo sector pattern to be produced using data mapping that is ordinarily used for the radially aligned servo sector pattern. Thus, curvilinear servo sector patterns with a desired resolution are produced without increasing computational overhead or memory requirements, or decreasing throughput. The delay can be converted into control settings such as sector delay, clock cycle delay and residual fractional delay settings that each represent a portion of the delay.

Abstract: The present invention provides a method and apparatus for detecting data received from a magnetic storage channel having a channel pulse response represented by a polynomial including intersymbol interference (ISI) terms. The detector includes a Viterbi detector corresponding to a trellis structure having states connected by branches having associated branch metrics. In one embodiment, the Viterbi detector includes a branch metric calculator component configured to calculate a branch metric associated with each of the plurality of branches by removing a contribution to the branch metric associated with a predetermined ISI term.

Abstract: A method for processing a plurality of mirror assemblies formed together from a silicon wafer. The method includes the steps of exposing the mirror assemblies to an acid release etch to produce released mirror assemblies and rinsing the released mirror assemblies to produce washed mirror assemblies. The washed mirror assemblies are dried to produce dried mirror assemblies and the dried mirror assemblies are mounted onto a mounting tape to produce mounted mirror assemblies. The mounted mirror assemblies are diced or scribed to produce a plurality of separated mirror assemblies, which are separated from the mounting tape so as to produce a plurality of discrete mirror assemblies.

Abstract: A disc drive, includes a base, a disc stack rotatably attached to the base, and an actuator assembly movably attached to the base. The actuator assembly also includes a bearing housing, head mounting arms, head suspensions attached to the head mounting arms and a head assembly attached to the head suspension. The disc drive also includes a hub having a cylindrical body. The hub includes a disc mounting flange on one end of the hub. A disc has an opening therein sufficient to allow the hub to fit within the opening of the disc. The disc has two substantially flat data surfaces. The disc also includes a disc clamping portion located near the opening in the disc. A clamp is used to attach the disc to the hub. At least one disc is placed onto the hub and onto the mounting flange of the hub. The clamp is then used to clamp the disc to the hub. The disc clamping portion includes features for accommodating differences in flatness between the disc surfaces, the mounting flange of the hub and the clamp.

Abstract: A method formats disc surfaces in a disc drive for storage of data in a group of tracks on the disc surfaces. The disc drive performs seek operations to seek among cylinders on the disc surfaces as a function of time according to an actual seek profile. An approximation of the actual seek profile is determined such that the actual seek profile falls within the approximation. The disc surfaces are formatted according to the approximation of the actual seek profile.

Abstract: An optical head is provided for transmission of light between a source of light and a storage location along an optical path that includes at least one offset optical element.

Abstract: A damper for dampening resonance created by a voice coil motor of a disc drive and transmitted to a supporting enclosure, the resonance capable of creating noise signals to the disc drive servo control system. The damper has a dampening member and a liner, the liner being a magnetically permeable member that is magnetically attracted to the voice coil motor and thereby pressingly engaging a magnet housing of the voice coil motor. In a preferred embodiment the dampening member is an acrylic polymer. In an alternative embodiment the dampening member is a fluoroelastomer. The magnet housing has characteristic features that increase the magnetic flux to the liner.

Abstract: A layer of iron—silicon—aluminum alloy is deposited over a seedlayer of an amorphous alloy to form a shield for a read element in a recording head. Percentage weights of iron, silicon, and aluminum in the iron—silicon—aluminum alloy are each selected such that the alloy has both near-zero magnetostriction and distinct magnetocrystalline anisotropy. Use of the amorphous alloy seedlayer results in greater magnetocrystalline anisotropy in the shield.

Abstract: An apparatus and method are disclosed for minimizing settling time in a disc drive servo system. The disc drive includes a head adjacent a rotatable disc on which a plurality of tracks are defined and a motor which controllably positions the head in response to current applied to the motor. A servo circuit is provided to settle the head onto a destination track at the conclusion of a seek operation by determining velocity of the head at a selected distance from the destination track, comparing the velocity to a desired velocity of the head at the selected distance from the destination track, adding a settling gain to a current command signal to generate a modified current command signal in relation to a difference between the velocity and the desired velocity, and using the modified current command signal to settle the head onto the destination track.

Abstract: Nonmagnetic substrate disks used to fabricate magnetic data storage media are surface treated prior to laser texturing, to enhance characteristics of the resulting texturing features and the surface topography provided by the features. In one approach, nickel-phosphorous plated aluminum substrates are maintained in an aqueous silicate solution, preferably sodium metasilicate at about a 5 percent concentration, by weight. An alternative approach involves maintaining the substrates in an aqueous borate solution, for example, sodium tetraborate decahydrate at about 5 grams per liter. In both cases a silicate or borate is deposited onto the substrate, forming an oxidation layer that changes the surface characteristics at and near the substrate surface, more particularly to a depth of 50-60 angstroms beneath the surface. The changes in surface composition include a reduction in the nickel concentration, and an increase in either silicon or boron. As a result, subsequent laser texturing produces features, e.g.

Abstract: An apparatus in accordance with the present invention provides a single or multi-layer coating to the surface of a plurality of substrates. The apparatus may include a plurality of buffer and sputtering chambers, and an input end and an output end, wherein said substrates are transported through said chambers of said apparatus at varying rates of speed such that the rate of speed of a pallet from said input end to said output end is a constant for each of said plurality of pallets.

Abstract: A magnetic recording medium exhibiting high in-plane anisotropy at low Mrt is formed employing a NiAl seedlayer and a CrMn underlayer thereon. Embodiments include magnetic recording media with a CoCrPtTa magnetic alloy layer exhibiting a Hr greater than 2800 Oe with a Mrt no greater than 0.5 memu/cm.sup.2. The resulting media also exhibit high S* and low media noise.

Abstract: Embodiments of the invention are directed to an etching apparatus for removing impurities from the surface of a substrate, such as a pallet and disc. Embodiments of the etching apparatus comprise a magnetic source, a cleaning chamber, a substrate transportation mechanism and a power source. The magnetic source is placed within the cleaning chamber, or vacuum chamber, which is configured to bombard the magnetic source with plasma. The substrate transportation mechanism resides within the cleaning chamber and is used to pull the pallet through the chamber between the spacing between the magnet towers. The power source, which is a DC source, is coupled to the pallet and produces an electric field which ionizes the plasma.

Abstract: A storage media is provided. The surface of the media is made to vary by an insubstantial amount relative to a datum to provide for improved flyability of a head over the surface.

Abstract: The method disclosed is generally directed to a process for controlling the velocity of an actuator arm assembly during a load from a ramp. A process in accordance with the invention includes applying an alternating current to the VCM to eliminate frictional effects. An increasing current is applied to the VCM. The increasing current is an increasing function of time in one embodiment of the invention and is determined such that the heads are loaded at a predetermined velocity. In one embodiment, the predetermined velocity is 1 in/sec.

Abstract: An apparatus that compensates for the asymmetry and the baseline shift in the signal generated by a magnetoresistive head. The apparatus stores a first correction factor for the baseline shift, a second correction factor for correcting the amplitude of the positive portion of the signal and a third correction factor for correcting the amplitude of the negative portion of the signal. The first correction factor for correcting for baseline shift is added to the signal generated by the magnetoresistive head to generate a baseline corrected signal. The baseline corrected signal is then monitored for positive and negative excursions from the baseline and the positive excursions are multiplied by the second correction factor and the negative excursions are multiplied by the third correction factor for generating a compensated signal.

Abstract: The present disclosure concerns a method and apparatus for accessing a memory device, such as a dynamic random access memory (DRAM). The DRAM has a plurality of rows, wherein each row has a plurality of DRAM paragraphs comprised of a plurality of contiguous columns. A linear shift register (LSR) translates a plurality of logical addresses to corresponding physical address locations in the DRAM. Each translated physical address is comprised of a row address and a column address. A physical address, including the row and column addresses, is accessed from the LSR. To access the DRAM paragraph at the accessed physical address, the row in the DRAM at the accessed row address location is strobed to setup and precharge the row. Following, all columns in the DRAM paragraph at the accessed physical address are strobed. After strobing the columns in a DRAM paragraph, the next physical address in the LSR, including the next row and column addresses, is accessed.

Abstract: A multiple disk drive storage system includes a latch assembly for positively latching a head positioning actuator arm when the head is positioned on a load/unload mechanism at the outer perimeter of the disks. Latching and unlatching cycles of the latch assembly are effected by interaction of the actuator arm motion and a latch arm retention magnet structure. In the latch position, the actuator arm is mechanically captured by a hook shaped latch head at one end of the movable latch arm, so that, even in a power off condition the actuator arm is positively latched by the combination of the actuator arm motion limitations, the latch head shape, the latch arm motion limitations and a bias spring urging the hooked latch head into a permanent, static latch with the actuator arm. The opposite end of the latch arm is provided with a magnetic mass which is attracted and held by the retention magnet.