Abstract: A method provides for waiting for a cache hit in the operation of a disk drive. The drive has an intelligent interface for communicating with a host, a magnetic disk, and a cache. The cache is divisible into a number of segments, and the cache employs a cache control structure. The drive receives a first command and a second command wherein the second command has a requested data range. The method comprises the steps of: (a) initializing a read in response to the first command to provide prefetch data to the cache in a prefetch data range wherein the prefetch data range has a first logical block address; and (b) waiting for a cache hit in response to the second command wherein the beginning of the requested data is within the prefetch data range and does not request the first logical block address.

Abstract: A disk drive has a base, a cover, a spindle motor mounted to the base, and a disk coupled to the spindle motor. A rotary actuator comprising a head stack assembly is coupled to the base by a pivot bearing assembly. The pivot bearing assembly provides a stationary member, a bearing, and a sleeve member for rotatably supporting the actuator. The pivot bearing assembly further provides an elastomeric interface between the stationary member and the actuator such that vibratory motion imparted to the head stack assembly is dampened by the elastomeric interface.

Abstract: A method is practiced in a disk drive in which a cache is divided into segments each having a segment priority. The method provides for managing the segment priority. The drive has an intelligent interface for communicating with a host, and a magnetic disk. The cache employs a cache control structure including a cache array with a cache array entry. There is a cache array entry for each one of the number of segments. The method comprises the steps of: maintaining the cache array entry wherein each cache array entry classifies a segment by a cache access type, wherein the cache access type is selected from a plurality of access types including sequential and random; and determining whether to change the scan priority of each segment based on the cache access type.

Abstract: A stationary vacuum deposition machine is used in a method for controlling the height of bumps formed in annular regions of substrates; the substrates are transported to the machine in a first condition in which each substrate is subject to a chemicapillary effect when subjected to localized thermal heating and melting. The machine includes a series of stations including an entrance station for receiving substrates into the machine, first and second predetermined stations, and a transport for operating in a cycle with each cycle including a transport phase and a stationary phase such that the transport causes all the substrates that are in the machine to be moved during the transport phase, and be temporarily held stationary during the stationary phase, such that during each stationary phase a predetermined one of the stations is occupied by one of the substrates while each of a plurality of others of the stations is occupied by a respective one of a plurality of others of the substrates.

Abstract: A magnetic disk drive includes a base which supports a head stack assembly having a coil portion, a flex circuit cable having a grounding portion, and a flex clamp. The disk drive further includes a voice coil motor (VCM) formed from the coil portion's interaction with upper and lower VCM plates that carry at least one permanent magnet. The disk drive includes a Z-shaped grounding portion which wraps around one end of the flex clamp and permits a single screw to secure that end of the flex clamp to the base and simultaneously make grounding contact with the grounding portion and an elongated protrusion extending from one of the VCM plates that is adjacent to the flex clamp to hold that end of the flex clamp against the base when the VCM plates are fastened to the base.

Abstract: A method and apparatus for verifying that data written on magnetic disk media can be successfully recovered in subsequent read operations and ensuring that the data to be written is held by a buffer until a read-verify operation indicates that the buffer space storing the data may be relinquished for new operations.

Abstract: A magnetic disk drive includes a base which supports a head stack assembly having a coil portion, a flex circuit cable having a grounding portion, and a flex clamp and in which a voice coil motor (VCM) is formed from the coil portion's interaction with upper and lower VCM plates that carry at least one permanent magnet. The disk drive includes a Z-shaped grounding portion which wraps around one end of the flex clamp and permits a single screw to secure that end of the flex clamp to the base and simultaneously make grounding contact with the grounding portion and an elongated protrusion extending from one of the VCM plates that is adjacent to the flex clamp to hold that end of the flex clamp against the base when the VCM plates are fastened to the base.

Abstract: A spindle motor of a disk drive is controlled in a switched voltage mode. A power bus supplies a voltage to the spindle motor. The power bus voltage is subject to variations while the spindle motor is being driven. An uncompensated motor voltage signal is modified to provide a compensated signal having a modified duty cycle. The modified duty cycle is inversely proportional to the variations in the power bus voltage. Commutation logic uses the compensated signal to generate commutation commands, which cause a power driver stage to energize the windings of the spindle motor.

Abstract: A magnetic disk drive with a head stack assembly includes a body portion, a coil portion cantilevered from one side of the body portion, and an actuator arm cantilevered to the opposite side of the body portion, wherein the body portion includes a plastic inner sleeve to provide a quick, press-fit connection with a pivot bearing cartridge. The body portion further includes a non-plastic outer portion which is preferably part of an aluminum E-block having integrally formed actuator arms. The plastic inner sleeve and non-plastic outer portion preferably include a spline and a recess, respectively, that are firmly compressed together by the press-fit connection to prevent relative angular motion. The plastic inner sleeve preferably includes a flat that is aligned with the spline and recess in order to contact the pivot cartridge along the flat and thereby ensure that the press-fit forces are focused onto the spline and recess.

Abstract: A method of managing commands is provided for a disk drive having an intelligent interface for communicating with a host. The drive also has a magnetic disk, host side programs, disk side programs, and a cache wherein the cache is divisible into a number of segments. The cache employs a cache control structure including a cache entry table, a buffer counter, a block count, a host pointer and a disk pointer. The drive receives a first command and a second command with a cache access type. The method of managing commands comprises the steps of: processing the first command to assign the first command to a cache segment having a prefetch area; determining the cache access type of the second command; and if the cache access type of the second command is a skip ahead sequential access then decrementing the buffer counter and incrementing the host pointer to skip leading nonrequested data in the prefetch area for the first command.

Abstract: A system for powering a disk drive microprocessor using the back electromotive force (BEMF) generated by the still-spinning spindle motor after host DC power fails, and for parking the heads under microprocessor control in a manner similar to that of a conventional seek. The system detects failing host computer DC power, converts the BEMF to DC, applies the DC power to the microprocessor, and moves the heads toward the parking zone under microprocessor control in accordance with a seek profile or other suitable control method of a type conventionally used for seeking. Thus, the heads travel to the parking zone at controlled velocities that minimize the travel or seek time.

Abstract: A method provides for adaptively aging cache segments in a segmented cache in a disk drive. The disk drive receives commands via an intelligent interface from a host. The drive has a magnetic disk. The cache employs a cache control structure including cache parameters, wherein each segment has a scan count of the number of scans of a segment and an access type, and wherein the cache parameters include a maximum number of misses to indicate the maximum number of times a segment will be scanned without a cache hit. A scan count is maintained for each segment while processing commands from the host. The maximum number of misses is adaptively adjusted based on the access type of the cache segments. The scan count for a segment is compared to the maximum number of misses to determine if the segment should be aged out.

Abstract: A method of operating a disk drive having a cache provides for adapting the amount of prefetch. The drive also has an intelligent interface for communicating with a host, and a magnetic disk. The cache is divisible into a number of segments, and employs a cache control structure including a cache array with a cache array entry. When the drive receives a first command, the method provides a step of performing a scan of the cache to assign the first command to a segment. The method further includes the step of maintaining the cache array with a cache array entry for each one of the number of segments, where each cache array entry classifies a segment by a cache access type, wherein the cache access type is selected from a plurality of access types including sequential and random. The method further includes the step of determining a limit on the amount of prefetch based on the cache access type for the first command and a cache environment variable. The limit may be a minimum prefetch or a maximum prefetch.

Abstract: Apparatus and means for attaching the head-suspension assembly to the actuator arm in a disk drive. A head-suspension assembly in a first fabrication step is permanently fastened to a nut plate, for example, by laser welding. The nut plate is fastened to the suspension assembly on the suspension surface that faces away from the nearby recording disk when the disk drive is fully assembled. Another aspect of this invention is the use of heat-activated thermosetting adhesive. The head-suspension assembly with the affixed nut plate is fastened to an actuator arm with a heat-activated adhesive film. In one embodiment, the adhesive is applied to both sides of a thin plastic film for ease of handling and application. In another embodiment, the adhesive is made electrically conductive to provide an electrically-conductive path between the actuator arm and the head-suspension assembly.

Abstract: A head disk assembly includes a base, a cover attached to the base and a spindle motor mounted to the base. The spindle motor includes a shaft, an inner cylindrical portion surrounding the shaft, and an outer cylindrical portion surrounding the inner cylindrical portion. The outer cylindrical portion has an annular surface and the inner cylindrical portion has a cylindrical surface which extends above the annular surface. The head disk assembly also includes a disk mounted on the spindle motor such that the disk surrounds the outer cylindrical portion; the disk includes a recording surface which is substantially co-planar with the annular surface. The head disk assembly also includes a disk clamp for clamping the disk to the spindle motor and a washer positioned between the disk clamp and the recording surface for transferring radial loads to the inner cylindrical portion of the spindle motor.

Abstract: A disk drive actuator assembly adapted for assembly in one of several configurations from a single line of modular components without a manually-supervised aligning step. The actuator improves manufacturability and inertia by introducing a common set of self-aligning modular piece parts. Each of several self-aligning modular components can be used to assemble any of several different actuator assembly designs. That is, a head-stack assembly (HSA) providing from one to six heads can be assembled using elements selected from single set of standardized modular components. The assembly process relies entirely on the self-aligning features of the standardized modular components, thereby eliminating the elaborate and error-prone manual assembly and alignment procedures known in the art.

Abstract: A frequency synthesizer has multiple modes of operation including a relatively short-duration frequency seek mode and a relatively long-duration normal mode. The synthesizer responds to a reference frequency signal and produces a periodic signal at a frequency that is a rational number times the frequency of the reference frequency signal. The synthesizer comprises a VCO, a feedforward state machine, a feedback state machine, a phase comparator, controllable gain circuitry between the phase comparator and the VCO, and logic circuitry that coordinates the operation of the feedforward and feedback state machines during the seek mode.

Abstract: A method for processing interface messages, such as SCSI messages, using an indexed jump table. Two single-dimensional tables are implemented by the method described. The first table stores index values for all valid sequence instruction locations for which an ATN signal can be detected. The second table stores index values for all valid interface messages. The index values of these two tables are used as entry points to the indexed jump table whose elements contain addresses to message handling functions.

Abstract: A method for manufacturing a recording medium on a hard disk includes forming a data recording layer on the disk, forming a nitrogenated carbon overcoat layer over the data recording layer, (with or without intervening layers), and the processing data recording layer to protect it from the nitrogen used in the process of forming the nitrogenated carbon. In one approach, the step of processing the data recording layer is accomplished by forming a buffer layer between the data recording layer and the overcoat layer by depositing carbon on the data recording layer using a carbon deposition process excluding nitrogen, then forming the overcoat layer by depositing carbon on the buffer layer using a carbon deposition process that includes a nitrogen source.

Abstract: A debris barrier surrounds a transducer for preventing microscopic debris from migrating near the magnetic poles of the transducer in a disk drive. In one embodiment, the debris barrier is composed of a barrier wall and a barrier cavity and used with a thin film transducer. The barrier elements are disposed within a region of an air bearing surface surrounding the poles of the transducer such that, during operation, debris is collected within and around the barrier thereby preventing the debris from migrating to the pole region. By eliminating debris around the transducer poles, this invention eliminates errors caused by the debris and thereby provides a more reliable disk drive. In another embodiment, the debris barrier is used with multiple transducers. In yet another embodiment, the debris barrier is used with a planar structure transducer having planar poles.