Abstract: A method, apparatus and computer program product for identifying electrostatic discharge (ESD) damage to a thin film device. The method includes (1) determining a cold resistance of the thin film device, (2) determining a hot resistance of the thin film device, (3) calculating a heating delta resistance (HDR) from the hot and cold resistances and (4) comparing the HDR to a threshold value to ascertain if the thin film device has suffered ESD damage. The HDR of the thin film device is characterized by the following relationship: HDR=(hot resistance-cold resistance)/(cold resistance).

Abstract: An active bypass circuit for use with a battery pack having a plurality of cells and method of operation thereof. The active bypass circuit includes a first switching device that is series-coupled with a cell in the battery pack (a separate active bypass circuit is utilized for each cell in the battery pack). A second switching device is parallel-coupled across the first switching device and the cell. The first and second switching devices are switched, i.e., turned ON and OFF, in a complementary fashion. The active bypass circuit also includes a monitoring circuit for monitoring an electrical characteristic of the cell and generating a switching control signal, in response to the monitored electrical characteristic, to selectively control the operation of the first and second switching devices. In an advantageous embodiment, the electrical characteristic is a voltage across the cell.

Abstract: A method and apparatus for monitoring the quality of the readback signal of data written on a magnetic recording disk in a disk drive and for limiting data loss due to physical damage at a slider/disk interface. The amplitude of a read signal is continuously monitored in the read channel, either by directly measuring the read signal amplitude or by monitoring the amplification level of the automatic gain control (AGC) circuit in the read channel which is inversely proportional to the read signal amplitude. If the amplitude of the monitored read signal decreases below a chosen level, the location of the data on the disk track is flagged as possibly damaged. The data is rewritten at the same location and then reread to see if full recovery of the degraded data is possible. If the amplitude read signal of the rewritten data is greater than a chosen level, the disk track is judged to be usable and normal operation continues.

Abstract: The present invention relates to a testing method and tester which reliably flags errors in disk drives, thereby reducing disk failures. In the testing method and tester, a random error due to noise occurs anywhere in a sector (read)/cylinder (write), whereas a repeatable error occurs in a specific area on a disk. If a plurality of random errors occur in the same sector or cylinder, no flagging is performed if the occurrence positions are distant from each other.

Abstract: The present invention relates to a process for the formation of components for use in a disk drive having graded properties. Particularly, the invention provides a method for forming a metal matrix composite components having graded properties. The graded properties are achieved by, for example, locating differing amounts of reinforcement material in different portions of a component and/or locating different compositions of reinforcement material in different portions of a component. Silicon carbide particles, for example, provide a low density reinforcement to an aluminum metal matrix creating a metal matrix composite having greater strength stiffness and damping.

Abstract: An antireflective composition includes a polyphenolic polymer which has a first repeating unit and a second repeating unit of the formula: wherein each of R1, R2, R3, R4, and R5 is individually a hydroxy group, hydrogen or an azo dye and only one of R1, R2, R3, R4, and R5 is a hydroxy group.

Abstract: A hard disk drive contains magnetic disks which are accessed by a series of pivotable arms. Each arm has a pair of flexible, cantilevered suspensions and a head gimbal assembly with a magnetic read/write head secured to each suspension. A tab extends from and forms part of the end of each head gimbal assembly. The hard disk drive also has a stationary cam member located near the outer edges of the disks. The cam member has a series of rigid cantilevered fingers with contoured surfaces. Each surface has three spaced-apart detents with a recess located between each adjacent pair of detents. The second recess on each surface has a lubricant-filled reservoir. For the majority of its operation, the drive pivots the arms between an operational range adjacent to the disks, and a park position in the first recess when the drive is not in use. The tabs slide along the support surfaces of the fingers when the arms move to the retracted position.

Abstract: A method of forming an computer component having improved damping capability is described. The method comprises providing a die for forming an computer component, inserting a water soluble salt block having a desired hollowing form into the die, and injecting formable material such as die-castable or thixoformable material in fluid form into the die such that the fluid forms around the salt block and substantially covers the salt block. Once the formable material solidifies to form the computer component, the solid computer component is subjected to pressurized steam to dissolve the salt within the solid component, thus leaving a hollow core of the desired hollowing form. The salt block can have at least one which forms an outlet opening in the solid computer component. The computer component can be, for example, an computer arm or an E-block for a computer hard drive.

Abstract: A magnetic media tape cartridge has a housing with a spool of magnetic tape wound on the spool. The tape is two-sided so that information can be recorded on both sides. The sides of the tape maintain an orthogonal planar orientation relative to the axis of the spool at all times. The housing has separate openings for accessing each side of the tape. A leading end of the tape protrudes through a third opening in the housing for offloading the tape onto a take-up reel. A door is pivotally mounted to the housing at each of the first two openings for covering and uncovering each side of the tape. The tape cartridge also has an indicator for indicating which side of the tape is being recorded or accessed.

Abstract: A mounting for a computer accessory such as a hard disc drive comprises a tray (2) for accommodating the accessory (1) which can be inserted into a mounting bay in the computer against the bias of a pair of springs (4). The tray (2) carries a bezel member (7) movable along the insertion path independently of the tray to latch or unlatch the tray in place, using latching members (6) in association with latching tracks formed in the bezel, by way of a push-push action.

Abstract: The present invention provides a disk drive, a loading/unloading apparatus, and a method for controlling the apparatus, capable of improving the reliability of data by performing stable speed control.

Abstract: A glide head for burnishing or smoothing the surface of a magnetic disk has an air bearing on one side and a piezoelectric element on an opposite side. The air bearing comprises a patterned set of four or five air bearing surfaces (ABS) and etched pockets having multiple depths in the air bearing. The air bearing preferably has two front ABS, two middle ABS, and one rear ABS. This configuration gives the air bearing superior performance characteristics over prior art designs. When the glide head contacts a defect or asperity on the surface of the disk, the glide head vibrates and causes the piezoelectric element to become excited and emit a signal in response.

Abstract: A ferrofluid seal for a hard disk drive actuator bearing has two circular plates which are axially spaced apart about a nonmagnetic pivot shaft of the actuator. The plates are parallel and in close proximity to one another. The upper plate is made of magnetically-conductive steel and is mounted to a stationary sleeve which surrounds the shaft. The lower plate is mounted to the shaft and has an annular magnet with pole pieces on an upper surface. A magnetic ferrofluid is located between the magnet and the upper plate to complete the magnetic circuit and form a seal. The ferrofluid seal prevents bearing emissions such as grease oil vapor and aerosol droplets from contaminating the disk drive.

Abstract: A spindle motor start up method wherein a torque balance between the stator and rotor is broken so as to avoid startup malfunctions, and thereby improve motor startup time in spindle motors prone to startup malfunctions, such as hard disk drive motors having a 4:3 ratio of the number of rotor magnetic poles to the number of stator slots.

Abstract: A tape cartridge assembly contains a spool of magnetic tape with a leader block on one end. The leader block inserts into take-up reel and the tape is initially wound at a higher than normal tension to create a small band of tightly wound tape on the reel. The band eliminates the effect of any mechanical distortion created by the leader block. The remainder of the tape is wound on top of the tight band at normal tension to form an outer band of distortion-free magnetic tape.

Abstract: A device for testing the take off speed of a thrust bearing in a disk drive spindle motor is disclosed. The device has a stationary torsion transducer that is used to support a drive shaft of the spindle motor. A load motor located adjacent to the transducer rotates the motor about the shaft while applying a radial load to the spindle motor through a belt. The load motor is attached to a linear stage which generates selected radial loads. In one version, the device also uses a ring magnet to attract the housing of spindle motor. The magnetic attraction imposes an axial force on the spindle motor and an equal reactive load on the thrust bearing. The axial load is such that the take off speed for the thrust bearing is much greater than that for the journal bearings. Under these conditions, the friction torque is dominated by the thrust bearing so that an accurate assessment of its quality may be assessed. As an alternative to the magnet, air jets may be used to apply a similar axial load to the thrust bearing.

Abstract: The invention relates to a magnetic recording data storage device which can operate effectively at high rotational speeds. The magnetic recording device of the present invention comprises (a) a magnetic recording disk, (b) a spindle motor, (c) a head supported on an air bearing carrier, and (d) an actuator connected to the head carrier for moving the head across the rotating disk. The spindle motor comprises ball bearings lubricated by a grease comprising a polymeric amine and bis or tris (alkyl phenyl)phosphate. The grease improves rotational operation of the disk drive.

Abstract: The present invention is a magnetic disk drive for reading or writing magnetically, comprising: (i) a base plate; (ii) a plurality of magnetic disks; (iii) a hub fixedly attached to the disks for supporting the disks; (iv) a motor operable to rotate the hub; (v) a plurality of magnetic read/write heads, each associated with the surface of a disk; (vi) an actuator for supporting the heads and moving the heads across the disks; (vii) a support shaft attached to the base plate; and (viii) a load/unload structure for displacing the heads from the disk comprising an elongated body, a base portion fixedly attached to the base plate and a plurality of ramps extending outwardly from the body. The body of the structure is mounted through one or more holes in the body onto the support shaft so that the support shaft extends along the length of the body to support the structure.

Abstract: A test connector for making electrical tests on a disk drive on a high volume manufacturing line. The test connector comprises a high density connector header for electrical connection to a disk drive electrical connector fixed to a printed circuit board (PCB) card having well-separated, large area contact pads electrically connected to the contacts on the connector header. The well-separated, large area contact pads on the test connector provide contact points for test probes from automated testers on the manufacturing line. Use of the test connector with its well-separated, large area contacts increases the reliability of electrical testing procedures with automated testers by reducing accidental shorting between test probes and by increasing contact alignment tolerances.

Abstract: A method for writing circular track position information on a magnetic recording disk comprising the steps of (i) rotating the magnetic recording disk, and (ii) aerodynamically floating in a helium atmosphere a magnetic recording head adjacent to the disk and writing with the head circular track position information on the disk.