Abstract: The disk drive provides a method of adaptively managing a cache segment divided into chunks by defining an unavailable data type to be stored in an element of a chunk array which indicates that the chunk is not available, and defining an available data type to be stored in an element of the chunk array that indicates the chunk is available and that indicates the number of consecutive chunks that are available. The disk drive also computes a number of chunks needed to fit the request length and scans the chunk array to find a first available element whose available data type meets a predetermined criteria for the number of chunks needed to fit the request length.

Abstract: A magnetic storage disk drive having a servo burst pattern which asymmetrically increases the linear region in which a read head may be micro-jogged from a burst pair center line to align the read head with a data track. The innovative servo pattern comprises a first pair of servo bursts that define a first burst pair centerline for writing a particular data track to a data track side of the first centerline, and a second pair of servo bursts collectively define a second burst pair centerline that is positioned to the data track side of the first burst pair centerline and is sufficiently close to the first burst pair center line so that the read head "sees" the second pair of servo bursts before "losing" the first pair of servo bursts when micro-jogged to the data track side for reading. The second burst pair centerline should be no farther from the first burst pair centerline than the linear read width of the read head.

Abstract: An initialization for runout cancellation for a hard disk drive such as a Small Computer System Interface (SCSI) hard disk drive. The hard disk drive at a servo sample rate updates a set of state variables. At an index wedge the state variables are stored to a memory. Upon a command to perform a head switch the hard disk reads the previously stored state variables from the memory. The previously stored state variables are used to adjust the repeatable runout based on the location of a head relative to an index wedge.

Abstract: A magnetic disk drive with a head stack assembly includes a body portion, a main flex circuit, an actuator arm cantilevered from the body portion and a head gimbal assembly supported at the actuator arm. The actuator arm includes a proximal end and a distal end, a first side surface and a second side surface A first array of conductive traces is supported at the first side surface and a second array of conductive traces supported at the second side surface. Each conductive trace includes a proximal conductive pad proximate to the proximal end of the actuator arm, a distal conductive pad proximate to the distal end of the actuator arm and a conductive path between the proximal and distal conductive pads. The head gimbal assembly includes a load beam having a base region abutting the actuator arm, a head coupled to the load beam, first and a second array of base region conductive pads, each array of base region conductive pads positioned on the base region and for electrically connecting to the head.

Abstract: A magnetic disk which includes a thin film magnetic layer resistant to thermal erasures caused by a rise in localized temperature in the disk due to head disk interference includes a substrate having a thermal diffusivity of less than about 2.times.10.sup.-6 m.sup.2 /sec and a magnetic layer for storing information which is subject to erasure upon such use in localized temperature generated by the head disk interference. An underlayer below the magnetic layer is provided for orienting crystalline structure of the magnetic layer, and the heat sink layer directly above the substrate and directly below the underlayer has a single material such as chromium. The heat sink layer has sufficient thermal diffusivity and sufficient thickness for dissipating heat generated by the rise in localized temperature caused by head disk interference to prevent the erasure of stored information in the magnetic layer.

Abstract: A head disk assembly for a hard disk drive having a mechanical actuator latch subassembly. The head disk assembly includes an enclosure, a disk, a pivot bearing cartridge, and a head stack assembly. The enclosure includes a base that preferably includes integral side walls. The disk has a recording surface that has an annular landing zone. The head stack assembly includes a head supported to be moved radially relative to the recording surface and to be brought to rest at a position in the landing zone. Significantly, the head disk assembly also includes a unitary latch base member and a unitary pivot latch member. The unitary latch base member has a mounting portion for mounting the latch base member to the base, an arm extending parallel to the major interior-facing surface, an inner crash stop post including an engaging end, and a pivot post. The arm also includes a spring holding post. The unitary pivot latch member has a bore surrounding the pivot post to allow pivot motion of the pivot latch member.

Abstract: A method is provided for managing a cache in a disk drive having an intelligent interface for communicating with a host. The drive includes a magnetic disk, and the cache is divisible into a number of segments, and employs a cache control structure including cache parameters. The drive receives a first command and a second command. The method comprises the steps of: performing a scan of the cache to assign the first command to a segment; compensating the cache parameters in response to the scan; and performing a scan to assign the second command to a cache segment prior to caching of data requested in the first command.

Abstract: A disk 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, with each segment having a cache access type. The number of segments may be varied in practice of a method for adaptively segmenting the cache. The method comprises the steps of: (a) calculating a plurality of caching factors while processing commands from the host; and (b) regularly determining whether to change the number of segments wherein an increase of the number of segments is effected based on a weighed weighing of the plurality of caching factors.

Abstract: A method provides for managing commands received by a disk drive via an intelligent interface from a host. The drive has a magnetic disk, and a cache with the cache being divisible into a number of segments. The cache employs a cache control structure including a cache environment variable. The drive receives a first command that requests data and a second command. The method comprises the steps of: processing the first command and caching only the requested data from the disk drive; and processing the second command and caching prefetched data for the second command if the second command is determined to be sequential with the first command.

Abstract: A magnetic disk drive with a head stack assembly having a pass-through flex circuit cable is disclosed. The pass-through flex circuit cable is mounted to a side of the head stack assembly to extend straight forward in an initial unfolded position during handling and assembly and to then be folded over into a final position in a substantially opposite direction and with a desired flex cable trajectory. The head stack assembly includes a post, preferably of rectangular profile, that is integrally formed and spaced away from the actuator body. An outer surface of the post defines the flex cable trajectory. The flex circuit cable, located in the space between the actuator body and the post, extends past the post in the initial position and wraps around the post in the final folded over position. The flex circuit cable is secured to the post in the final folded over position, preferably with a flex clip that removably mounts to the post.

Abstract: The invention is a method of calibrating a position error signal (PES) to overcome the problem of a measured displacement or PES that varies as a non-linear function of real displacement when the read transducer is positioned to either side of a null position where the PES equals zero. The PES is notably nonlinear while reading servo burst information with a Magneto-Resistive (MR) head which has nonlinear magnetic characteristics. The method uniquely calibrates the measured PES to provide a corrected PES without requiring any knowledge of the actual displacement from the position where the measured PES equals 0. The calibration according to this method, therefore, may be performed at anytime without need for real displacement information from a servowriter or any sort of special calibration track.

Abstract: A method and apparatus for texturing a landing zone on a substrate of a magnetic disk to reduce stiction between a magnetic transducer head and the disk is provided. The method includes projecting discrete pressurized fluid droplets to impact a substrate surface of the substrate with sufficient momentum to form cavities in a selected annular area of the substrate surface, the selected annular area with cavities therein being of sufficient width to provide a textured landing zone for the magnetic transducer head. A magnetic disk for storing data readable by a transducer head is also provided. The disk includes a rigid substrate. A textured landing zone is provided on the disk for engaging the transducer head. The textured landing zone is formed by the steps of directing a stream of discrete pressurized fluid droplets against the substrate to create roughness therein and moving the substrate and stream of droplets relative to one another in order to create an annular area of roughness.

Abstract: The invention resides in a magnetic disk drive having a load beam assembly that forms a part of a head gimbal assembly and head stack assembly in a magnetic disk drive.The load beam assembly is uniquely mass balanced to prevent head slap by preventing an acceleration in the Z-direction from causing the transducer head to separate from the disk. The load beam assembly is preferably mass balanced by providing a load beam balancing member that is rigidly connected to the elongated load beam about a transverse axis of the hinge member. The balancing member can form the balancing mass or the balancing member can carry a discrete balancing mass. The balancing member may be divided into two halves that move on either side of the base portion, but is preferably comprised of a narrow, centrally located member that moves within an aperture formed in the base portion. The mass balanced load beam assembly can beneficially be manufactured from the same stainless steel sheets used to form conventional load beam assemblies.

Abstract: A hard disk drive has an intelligent interface for communicating with a host, a magnetic disk, disk side programs and host side programs, and a cache. The cache is divisible into a number of segments, and the number of segments may be varied. The cache employs a cache control structure including a cache entry table, and the hard disk drive receives commands from the host in a queue. The method comprises the steps of. (a) receiving a first command and a second command from the host; (b) determining a scan first state; (c) determining if there are any commands in the queue; (d) waiting for a first command to complete and performing a seek if there are no commands in the queue and the scan first state is false; (e) performing a scan of the cache entry table to assign the second command to a segment; and () checking if a seek is needed for the second command and if a seek is needed for the second command performing a seek for the second command after the first command has completed.

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 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.