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.

Abstract: Adhesion between a deposited seed layer, e.g., a sputter-deposited NiP seed layer, on an alternate substrate, such as a glass, ceramic or glass-ceramic substrate, is significantly enhanced by depositing a chromium or chromium-alloy adhesion enhancement film between the substrate and seed layer. Magnetic recording media comprising a surface-oxidized NiP seed layer and chromium adhesion enhancement film exhibit low media noise and are suitable for high density longitudinal magnetic recording.

Abstract: An apparatus and method are disclosed for minimizing damage to a disc drive during head switching operations. The disc drive comprises a plurality of magnetic recording surfaces to and from which data are transferred using read/write heads, each head utilizing the application of a bias current during operation. To switch from a presently selected head to a target head, the disc drive determines a first value indicative of the magnitude of a bias current for the presently selected head and a target bias current to be applied to the target head. When the second value is greater than the first value, the disc drive switches from the presently selected head to the target head and then applies the target bias current; conversely, when the first value is greater than the second value, the target bias current is applied to the presently selected head and then the disc drive switches from the presently selected head to the target head.

Abstract: A glide testing apparatus includes a motor assembly, a sensor element, a positioning assembly, and detection circuitry. The motor assembly rotates a magnetic disk about an axis. The sensor element produces a detection signal in response to disk surface characteristics. The positioning assembly positions the sensor element at selected radii from the axis of disk rotation, and the detection circuitry receives a signal from the sensor element to detect movement of the sensor element between a first zone on the disk and a second zone on the disk. Methods of distinguishing between two adjacent zones on a magnetic disk include rotating a magnetic disk about an axis and positioning a sensor element at selected radii from the axis of rotation.

Abstract: A low inductance electrical compression connector for a disc drive interconnecting conductors of a flex circuit to conductive traces on a PCB, the electrical compression connector having a dielectric housing with a plurality of spaced apart insulator portions and conductive compression contacts disposed between the insulator portions. The insulator portions, the dielectric housing and the conductive compression contacts form open ended deflection cavities disposable above the PCB. First ends of the conductive compression contacts and solderable to conductive traces on the PCB, while second ends of the conductive compression contacts are pre-load spring contacts disposable above respective deflection cavities. Inserting the conductors of the flex circuit beneath the pre-load spring contacts into the deflection cavities causes the pre-load spring contacts to engage the conductors of the flex circuit to secure the flex circuit against the printed circuit while providing electrical contact.

Abstract: A latch for a disc drive, wherein the disc drive has an actuator that is pivotally supported for moving an array of read/write heads radially across a data storage disc between a parked location and a data storage location, the parked location providing a landing surface for the read/write heads when the disc drive is non-operational, the latch limiting the actuator from pivoting so that the read/write heads remain in the parked location while the disc drive is non-operational. The latch has a base member enabling attachment to the disc drive, the base supporting an inner stop and an outer stop which limit the actuator rotation, the base further supporting a cantilevered latch arm which biases a latch finger to a position whereat the latch finger and the inner stop form a latching groove and the latch finger and the outer stop form an unlatching groove, the actuator being confined by the latching groove in the latched mode and being confined by the unlatching groove in the unlatched mode.

Abstract: A disk drive system includes a base, a disk stack rotatably attached to the base, and an actuator assembly movably attached to the base. A ramp assembly includes a set of ramps for loading and unloading the transducing elements to and from the disks in the disk stack. The ramp assembly is attached to the base. The ramp assembly has a series of fixed ramps which are attached to a rigid structure. The ramps have four degrees of freedom which allow for adjustability in the formation of the ramp so that the E-block or actuator formed from separate parts can move with respect to the disks and with respect to the ramps without excessive interference to load or unload the sliders which carry the transducers with respect to the disk. Each individual ramp unit is an integral part. The individual ramp units are positioned with respect to a rigid structure and then fixed into the proper position by either laser ablation, rod melt approaches, adhesives or attachment with mechanical fasteners.

Abstract: A mounting system for attaching head suspension assemblies to actuator mounting arms of a disc drive actuator. The mounting system of the invention comprises mounting plates for the head suspension assemblies that include bosses inserted in cooperative holes in the actuator head mounting arms. Mounting discs of shape memory allow, in martensitic phase, having outer diameters selected for cooperation with the inner diameter of the bosses, are press-fitted into the bosses. The mounting discs are then heated to transform the material of the mounting discs to the austenitic phase. This transformation causes the outer diameter of the mounting discs to increase with sufficient force to deform the bosses of the mounting plates into interference fit with the holes in the actuator head mounting arms.

Abstract: An optical microswitch for use with a laser beam that extends along a path comprising a body having an inlet port adapted to receive the laser beam and a plurality of outlet ports. A plurality of mirrors coupled to a plurality of micromotors carried by the body. The micromotors selectively move the mirrors from a first position out of the path of the laser beam to a second position into the path of the laser beam to direct the laser beam to one of the outlet ports. Each of the micromotors has at least one electrostatically-driven comb drive assembly therein for moving the respective mirror to one of the first and second positions. A controller is electrically coupled to the micromotors for providing control signals to the micromotors.

Abstract: A method of creating an improved hydrodynamic fluid bearing is provided which is relatively insensitive to shock vibration changes in load and rotational speed. The hydrodynamic bearing motor in which the bearing is open at both the upper and lower ends, and in which the balance of fluid flow within the bearings is maintained. The assembly of the hydrodynamic bearing is more easily assembled, and the gaps are easily adjusted. In the design of the hydrodynamic bearing, the tolerances for assembly of the various components is minimized that is, the critical nature of many of the gaps is diminished.

Abstract: A method and apparatus for manipulating a magnetic disk to provide adaptive track pitch. A manufacturing station measures the actual radial width of an annular surface of the disk, which may include extra space. Wider-than-nominal track widths are then computed and utilized for writing data onto the disk.

Abstract: To control operations of an arcuate scanning head assembly, servo signals are written in one or more designated servo regions along a recording tape, for example along one or both edges of the recording area on the tape. To minimize the space occupied by the servo signals, the servo signals are always written with an azimuth that is substantially parallel to the longitudinal axis of the tape. In the preferred embodiment, servo signals aligned with adjacent tracks are written at two different positions within a servo region. As a read head passes over a track and the servo region, the head should overlap the servo signal aligned with that track and a portion of the servo signal aligned with the adjacent track. A control system samples the signal from the read head in a first time window corresponding to passage of the head across a burst aligned with the track and in a second time window corresponding to passage of the head across a burst aligned with the adjacent track.

Abstract: Method for removing random scratches formed during the polishing of magnetic recording media, and for disposing on the surface of the media a near-circumferential texture which increases the recording reliability of the media while simultaneously reducing its failure rate. The present invention teaches the application of a low unit load force to a large surface pad and polishing tape combination while in contact with a rotating disk surface that is also moving in a circumferential direction to completely remove the random scratches previously formed by a polishing step. The scratches are removed with the aid of a specially designed, extremely fine alumina slurry composition which prevent producing similar size circumferential scratches at the high surface speeds. The methodology provides for a smoother disk surface than prior known super-polish/texture methodologies.

Abstract: A disc mounting system for mounting the discs of a disc drive in a fixed radial relationship to the hub of a spindle motor, the disc mounting system including a composite disc spacer that maintains the discs in a fixed radial relationship to the spindle motor hub. The composite disc spacer includes a wedge member which supports a plurality of axially extending fingers which include inwardly and outwardly facing surfaces that bear against the spindle motor hub and against the bores of the discs to maintain the discs in a fixed concentric relationship to the spindle motor hub. The composite also has a spacer that extends about the wedge member to provide fixed relative axial spacing of the discs. The wedge member and the spacer interlock to facilitate handling of the composite disc spacer during assembly.

Abstract: An improved attachment of an actuator E-block of an actuator apparatus to a cartridge bearing assembly for a hard disc drive, the actuator apparatus having an E-block with a central bore having a pair of cartridge bearing alignment edges and a relief area, the cartridge bearing alignment edges disposed within the central bore to engage the cartridge bearing assembly. Mounting members extend through the wall of the E-block into the central bore to apply a frictional load there against and a compressive load against the cartridge bearing assembly sufficient to maintain contact between the cartridge bearing alignment edges of the E-block and the cartridge bearing assembly.

Abstract: A mirror assembly of micron dimensions for use in deflecting beam of light. The mirror assembly includes a planar base and a planar mirror spaced apart from the planar base and disposed generally parallel to the planar base. The planar mirror has first and second end portions and a longitudinal axis extending between the first and second end portions. First and second torsional members extend along the longitudinal axis and are connected to the respective first and second end portions for permitting the mirror to rock between first and second positions about the longitudinal axis relative to the planar base. The first and second torsional members are secured to the planar base. At least a portion of the mirror is made from a conductive material. First and second spaced-apart electrodes are carried by the planar base for driving the mirror between the first and second positions. A tether member extends transversely of the longitudinal axis and is secured to the first torsional member and to the planar base.

Abstract: A disk drive having a novel head-gimbal assembly (HGA) which is attached to an actuator arm of an actuator assembly. The HGA includes a read/write head, a flexure, and a suspension arm. The suspension arm has a first end including the flexure supporting the read/write head, and a second end including a hole having an attached swaging member extending through it. The swaging member includes a baseplate and a swaging boss which interface at an annulus region. A circular hole is formed through a top surface of the baseplate and extends downward partially through the swaging member. A non-circular hole, concentric with the circular hole, is formed through a bottom surface of the swaging boss, and extends upward partially through the swaging member. The non-circular hole has a smaller diameter than the circular hole. The shape of the non-circular hole may be any geometric shape such as a two-lobbed swaging hole, a three-lobbed swaging hole, an elliptical hole or a hexagonal hole.

Abstract: A memory system and a manner of operating the memory system are provided. The memory system includes several arrays arranged in groups of columns having a column address, and rows having a row address. Operating the system involves storing blocks of data in the arrays in a way that provides contiguous logical addresses for the blocks of data. A block of data is stored in a row of a group of columns in an array. The row address is incremented and the process repeated until a row limit is reached. Next, the process is repeated with another array until blocks of data have been stored in all rows of a corresponding group of columns in the array. The column address is incremented and the row address reset, and the process repeated until a column limit is reached.

Abstract: A magnetic disc storage system includes a base and a rotating magnetic disc having an axis of rotation. A transducing head which reads and writes information is positioned proximate the disc. The disc rotates on a rotating member relative to a fixed member which is attached to the base. In one embodiment, the hydrodynamic bearing has a shape which forms a portion of a sphere.