Abstract: A horizontal combined head is provided which has both a thin film write and an MR read element located at an air bearing surface (ABS). The read element can be formed with a track width that is independent of the track width of the write element. The MR sensor or the read element is separated from one of the first and second pole pieces of the write element by an insulation layer. Accordingly, the shields for the read element remain more stable after a write operation. In one embodiment of the present invention a single stripe MR sensor is employed while in a second embodiment a dual stripe MR sensor is employed. A method of the invention includes forming the dual MR stripe in a single process step so that the dual MR stripes of the dual MR sensor are near identical for implementing near absolute common mode rejection of noise.

Abstract: A radially and axially preloaded bearing that has a very low mass and axial profile and which can be used in a actuator pivot of a direct access storage device without the need for a second bearing to counter the preload. An outer race of the bearing is split in order to form an open ring. Three balls are placed between the outer race and an inner race. Both the inner surface of the outer race and the outer surface of the inner race are formed such that two contact points exist between each ball and each race. Alternatively, the outer race is a closed toroid. The inner race is radially split to form a lower and an upper race, each being a closed toroid. In yet another alternative, the outer race is radially split into an upper outer race and a lower outer race. The inner race is a single closed toroid. A limiter is used to limit the movement of each of the balls. Alternatively, a conventional ball cage is used.

Abstract: A sprinkler system for distributing water from a source substantially evenly over an area of terrain comprises a body defining a passage having an inlet connected to an outlet extending at an angle to the inlet, and a generally circular nozzle plate having a plurality of nozzles therein rotatably mounted at the outlet for selectively positioning a selected one of the plurality of nozzles in alignment with the outlet for distributing a stream of water outward from the housing, and the nozzle plate being selectively rotatable for selectively moving the nozzle plate to a selected nozzle position.

Abstract: A multilayered spin valve read head including an antiferromagnetic pinning layer and a ferromagnetic pinned layer which can maintain a high pinning field between the layers while minimizing the coercivity of the pinning layer. The apparatus and method of the invention comprise placing a thin discontinuous nonmagnetic interlayer such as Cu between the antiferromagnetic and the ferromagnetic layers.

Abstract: A program-controlled machine tool with automated tool changing, where the machine tool consists of a motor-driven machining unit with a working spindle that can be moved in at least one coordinate. The machine tool also includes a work table that can be driven by a motor in at least one coordinate, at least one tool magazine, and a programmable control unit. In order to be able to carry out tool changing operations without any auxiliary equipment, especially without a tool changer, within a short period of time, the tool magazine is mounted in a certain spatial arrangement with the working area of the machining unit so that its changing position can be approached directly by the working spindle in order to carry out the tool changing operation.

Abstract: A magnetic head structure including a magnetoresistive (MR) head and an inductive head for data storage devices such as tape drives. A method of fabricating a magnetic head utilizing semiconductor-type processing techniques is described that produces an inductive head gap having a substantially flat planar structure throughout in length which, in one embodiment, has a length of 150 microns and a height of one micron. The structure includes a first and second shield, and an MR layer formed therebetween that includes an MR sensor adjacent to the air bearing surface (ABS), leads connected on opposite sides of the MR sensor, and isolated segments situated between the leads and extending all the way to the ABS. A trench (i.e. gap) is formed between the leads and the segments. Preferably, the leads and the segments are deposited simultaneously, and the insulating gap is formed subsequently by photoresist and masking techniques.

Abstract: A sprinkler unit comprises a housing having an inlet for connecting to a source of water, an outlet, passage means connecting the inlet to the outlet, a nozzle detachably mounted in the outlet for distributing a stream of water outward from the housing, and a valve in the passage selectively operable for selectively stopping flow of water through the passage means to the nozzle and an actuator operable from the exterior of the housing for selectively operating the valve.

Abstract: A system manages data transfer between a computer, a data storage disk, and a data buffer which is associated with the disk. Upon receipt of a write request during data read-ahead from the disk to the buffer, the system preempts the read-ahead to write the data to the disk only when the target write track on the disk is different from the track being read ahead into the buffer. Otherwise, the system permits read-ahead to continue until the target write sector is positioned beneath the disk drive head. Also, upon receipt of a read request during cache writing from the buffer to the disk, the system immediately satisfies the read request prior to completing the cache writing when the requested read data is contained in the buffer. Moreover, the system provides for dynamic switching between a data read-ahead preempt policy and a data read-ahead no-preempt policy based upon parallel monitoring and comparison of data request service times under both policies.

Abstract: A composite thin film slider with a protruding R/W device formed by chemical-mechanical polishing to protrude above its substrate and thereby reduce the distance between the R/W device and the recording media. The slider includes a ceramic or non-ceramic substrate with a substantially planar bearing surface, and a R/W device. The R/W device includes an insulator and certain conductive R/W components, deposited onto the substrate's deposit end. The R/W components may include, for example, a magnetic shield layer, a MR stripe layer, and a magnetic pole tip layer, all layered over the deposit end of the substrate. The R/W components protrude from the insulator sufficiently to extend past the substrate's bearing surface. To manufacture this slider, a substrate with the R/W device deposited thereon is polished with a lapping slurry to disproportionately erode the substrate and insulator with respect to the R/W components.

Abstract: In a hard disk drive, power and signals are transferred through a flexible cable 42 between a carriage having a magnetic head reading magnetic information while the positioning of the magnetic head is controlled on a magnetic disk and a card provided on the lower surface of a base. The movable section 44 of the flexible cable 42 is supported by the carriage to follow the carriage. A nonmovable section 46 is bent so as to enclose a reinforcement plate 50 and installed on the base through the reinforcement plate 50. The reinforcement plate 50 is used as a reinforcement for installing an AE module 54 on the upper surface 52 thereof. The reinforcement plate is also used as a reinforcement for connecting a carriage connector 84 to the card 40 through the lower surface 60 thereof. The reinforcement plate is used for maintaining an attitude to maintain the attitude of the movable section 44 in the lateral direction on a surface 64 of thickness of the plate.

Abstract: A key establishment protocol between a pair of correspondents includes the generation by each correspondent of respective signatures. The signatures are derived from information that is private to the correspondent and information that is public. After exchange of signatures, the integrity of exchange messages can be verified by extracting the public information contained in the signature and comparing it with information used to generate the signature. A common session key may then be generated from the public and private information of respective ones of the correspondents.

Abstract: A computer-implemented method for minimizing the amount of time to access current data in a database which may be stored wholly in a DASD-oriented external storage subsystem or partly in DASD and partly in a stored high-speed electronic store while maintaining coherency of the data with respect to multiple user systems.

Abstract: A ceramic slurry is deposited onto a plastic carrier tape and allowed to dry before the tape is inverted for further processing. The plastic carrier tape remains with the ceramic during subsequent via hole punching and printing steps. The carrier tape also remains with the dried ceramic to support the same when the via holes are filled with conductive material which helps retain the material within the via holes. The carrier tape is peeled off as each layer of ceramic is built up to form a laminated multi-layer ceramic component. This provides a smooth, uniform surface at the top of each conductive-filled via hole. In order to ensure that the conductive properties of each conductive-filled via are not compromised a preparatory step of creating a hole in the plastic carrier tape that is very small in comparison to the via hole placed in the ceramic tape is included. The small hole in the plastic carrier serves as a bleed hole for air trapped in the conductive paste.

Abstract: A magneto-resistive read head having a "parasitic shield" provides an alternative path for currents associated with sparkovers, thus preventing such currents from damaging the read head. The parasitic shield is provided in close proximity to a conventional magnetic shield. The electrical potential of parasitic shield is held essentially equal to the electrical potential of the sensor element. If charges accumulate on the conventional shield, current will flow to the parasitic shield at a lower potential than would be required for current to flow between the conventional shield and the sensor element. Alternatively, conductive spark gap devices are electrically coupled to sensor element leads and to each magnetic shield. Each spark gap device is brought within very close proximity of the substrate to provide an alternative path for charge that builds up between the sensor element and the substrate to be discharged.

Abstract: A thin film conductive line is formed between MR pads on an MR head for protecting an MR sensor from electrostatic discharge (ESD) during assembly steps between row level fabrication of the head and prior to merge of a head stack assembly with a disk stack assembly. The conductive line may have a reduced thickness delete pad. A laser beam having a fluence sufficient to sever the conductive line at the delete pad but insufficient to damage or cause debris from structure underlying or surrounding the conductive line is used to sever the conductive line.

Abstract: A system for identifying and bounding the regions of a digital electronic logic design model that are affected by design revisions. The system is useful for improving the efficiency of incremental logic synthesis systems and includes procedures for recording the signals directly affected by user revision operations and for marking signals in the logic to identify those indirectly affected. A smart editor capable of parsing the formal register transfer language (RTL) in which the logic design is described is included in the system.

Abstract: A head gimbal assembly for disk drives is attached to an actuator arm using an adhesive. An etch pattern is formed in the mount plate of the head gimbal assembly, defining a mating surface area. An actuator arm is received by the mating surface area, the two members are suitably aligned, and an adhesive is introduced into the various channels that comprise the etch pattern through an access opening that is located outside of the mating surface area. By locating the access opening outside of the mating surface area, the adhesive may be introduced after a final alignment is achieved between the head gimbal assemblies and the actuator arms. Such manner of attachment may be used with individual actuator arms as well as when connecting head gimbal assemblies to an actuator comb assembly.

Abstract: A baseline correction circuit (BCC) compensates for the offset present on a pulse width modulated (PWM) signal in an optical readback system when associated transients first appear in the PWM signal, then compensates for the decay in the PWM signal so that significant baseline variations are minimized. The BCC includes a BCC switch coupled to switch the PWM signal responsive to a control unit and a low pass filter coupled through the BCC switch to receive the PWM signal. The low pass filter includes a capacitor coupled between the PWM signal and a ground reference, which stores the voltage of the baseline variation. A difference amplifier is connected to receive the low pass filtered output and also the PWM signal, and to provide a difference signal responsive to the difference between these two signals. The resultant signal is a high-pass filtered version of the PWM signal originally supplied to the BCC.

Abstract: An efficient method for adding one or more new direct access storage devices (DASDs) to a redundant array of independent disks (RAID) array without disrupting ongoing operation of the array. In one embodiment, after contents of new DASDs are initialized off-line, the "parity" or "data" status of specific storage locations in the array is re-mapped, without any changes to the storage locations' contents. In a second embodiment, RAID arrays are efficiently expanded and parallelism is facilitated for original as well as new data by re-mapping parity and data tracks, changing the contents of a minimum number of tracks and maintaining the contents of others.

Abstract: A magnetoresistive read/inductive write magnetic head assembly formed on a hard electrically insulating substrate and having electrostatic discharge protection comprises: a hard electrically insulating substrate, preferably formed of sapphire or alumina-TiC; multiple alumina layers formed over the substrate; a magnetoresistive read/inductive write head positioned between the alumina layers; a silicon layer supported by the substrate; and a semiconducting circuit integrated into the silicon layer and interconnected with said magnetoresistive read/write inductive write head to provide electrostatic discharge protection to the head. The silicon layer may be epitaxially grown on the substrate when implemented as sapphire, or bonded to the substrate when implemented as alumina-TiC. The hard electrically insulating substrate and alumina layers provide the assembly with a hard air bearing surface having generally uniform lapping and etching characteristics, and excellent durability.