Abstract: Apparatus and method for mounting a disc drive with vertical and horizontal compressible elements and for stabilizing the disc drive during use. Shock mounts are affixed to a horizontal surface (i.e. parallel to a data surface) of the disc drive, slowing vertical shock pulses transmitted from the frame to the disc drive. Recessed vertical surfaces are formed on sides of the housing to accommodate additional dampeners, which slow horizontal shock pulses while reducing operating vibration.

Abstract: Noise effects in a disc drive having a disc on a rotating spindle in a housing are reduced by inducing vibrations in the housing of the disc drive that at least partially cancel a characteristic acoustic noise signal of the drive.

Abstract: A Viterbi PRML system and method providing a new code with distance properties such that some tribits are allowed but no longer sequences are allowed. A code rate 8/ 9 is constructed for EPR4 and E.sup.2 PR4 channels and the system independently maps 8-bit blocks of user data to 9-bit channel sequences. The precoder has transfer function, f(D)=1/(1.sym.D), and produces a binary channel input x(D), which is fed to a coder, to provide an output signal y(D), which is transmitted and corrupted by noise. The corrupted signal is received and fed to a Viterbi detector. The signal is decoded to produce an estimate of the 8-bit data bytes, as reconstructed to be freed from noise corruption. The encoding protocol of the invention is implemented in the encoder.

Abstract: The method disclosed is generally directed to a process for controlling the velocity of an actuator arm assembly during a load from a ramp. A process in accordance with the invention includes applying an alternating current to the VCM to eliminate frictional effects. An increasing current is applied to the VCM. The increasing current is an increasing function of time in one embodiment of the invention and is determined such that the heads are loaded at a predetermined velocity. In one embodiment, the predetermined velocity is 1 in/sec.

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: 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 disk drive including voice coil magnet plates formed integrally with the base and/or cover of the disk drive. During the fabrication process, the steel magnet plates are placed in proper position in the base and cover die casting, and then the molten aluminum is injected to form the base and cover. As result, the magnet plates are integral with the base and cover and no fluid leakage can occur around the boundary between the top magnet and cover, or around the boundary between the bottom magnet and base. Thus, the disk drive is sealed against the external environment.

Abstract: An improved pivot mechanism for an actuator assembly of a disc drive having an E-block that supports plurality of read/write heads in data reading and writing relationship to an array of spinning data discs. The pivot mechanism has a bearing cartridge that supports the E-block and which pivots about a pivot shaft which supports a pair of ball bearings of the bearing cartridge. Each of the ball bearings contains only three balls that are evenly distributed circumferentially about the pivot shaft. Contact surfaces of the bearing outer race and inner race provide single-point contact between the races and the balls.

Abstract: A digital communication apparatus (20) transmits sectors of digital values that include error correction values used to detect and correct errors within the sector. Each sector consists of a number of blocks (70, 72, 74) and the error correction values of each block (70) are useful in correcting up to a maximum number of erroneous digital units (78, 84) in that block (70). The digital communication apparatus (20) encodes the blocks of digital units to transmit them through a channel (32) and then decodes the channel's representation of those encoded blocks, where the channel's representation occasionally contains burst errors.

Abstract: A digital peak detection system digitizes analog signals and provides absolute values to a series of one cycle delays, and to a sequence of comparator stages. Each digital sample is parallel compared to a number of preceding samples equal to the number of active comparator stages. Control signals activate comparator stages to determine sample comparison window length, including lengths exceeding the number of samples between recorded peaks. Peak detection is optimized using a variable gain amplifier whose gain is updated based upon amplitude difference between actual and desired peak samples. When sample amplitudes are smaller than a qualifier threshold, a countdown timer increases amplifier gain after lapse of a programmed time without detecting a qualified pulse. Gain is also updated when the analog to digital converter saturates. Initial gain values can be programmed, and gain stored at the end of a servo mode for future use in reducing gain control loop convergence time.

Abstract: A disk drive in which a movable latch locks the data transducer assembly to prevent movement due to shock. The movable latch cooperates with an actuator by engaging an actuator extension arm. The movable latch also engages a stationary magnet with one of two latching magnets. The movable latch arm is mounted to a shaft which extends into a sealed casing which incorporates a plunger. The plunger is located in a chamber filled with viscous fluid which is not subject to migration or outgassing from the chamber. The viscous fluid provides resistance to sudden movements of the plunger. Latch release is achieved by application of low continuous force to the actuator arm by a voice coil motor.

Abstract: The invention uses piezoelectric sensors to test disk drives. Both contact start-stop and load-unload type disk drives may be tested. A piezoelectric sensor is affixed to a disk drive to test for disk drive mechanical integrity. One method of affixing the sensor to the disk drive is using a mechanical clamp. The clamp is intended for repeated use on many disk drives, and therefore its easy removal is important. An alternative clamping apparatus is a magnetic clamp. In use, the clamp affixes the piezoelectric sensor to a disk drive in an optimal location with optimal force. Affixed piezoelectric sensors are used to detect aberrant behavior generated by non-optimal disk drive performance. The clamp/sensor combination detects acoustic signal in a disk drive which is used to determine whether or not a disk drive has adequate head-disk clearance. The apparatus is flexible, allowing testing after assembly of head-disk assembly and before or after servowriting and final disk drive assembly.

Abstract: A cold trap assembly having Peltier Junction assembly is provided to reduce the head stiction between a disc drive head and a disc. The Peltier Junction assembly includes a cold region which has a temperature lower than the ambient temperature of the disc drive. Vapors from outgassing components in the disc drive condense on the cold region, thereby reducing the amount of vapors which may condense on the disc surface.

Abstract: In a disc drive, a position error signal (PES) can be generated that is insensitive to the read element's magnetic and physical geometry and micro-track profile, and that has a spatial domain periodic frequency that corresponds to a frequency region of the micro-track profile that facilitates a high magnitude response. The servo pattern for generating this PES includes a first servo burst pair (A,B) and a second servo burst pair (C,D) of servo burst members, each pair written as normal and quadrature channels.

Abstract: A method for adaptively controlling the write inhibit signal in a disk drive apparatus. The disk drive apparatus include magnetic disks manipulated such that the total space that is to be allocated for storing data has been measured and recorded such that the tracks for storing data have been servo written at a wider spacing than a nominal track spacing. The drive's operational circuitry includes access to modified write inhibit threshold data that is based on the drive's nominal design track misregistration allowance, plus any track width increase gained by adaptively controlling the track pitch. The modified write inhibit threshold essentially facilitates an acceptable delay in activating a write inhibit signal. The data tracks on each of the magnetic disks have been servo written utilizing the wider track spacing while maintaining the track misregistration allowance that corresponds to the nominal track spacing.

Abstract: An improved attachment of an actuator E-block of an actuator assembly to a pivot bearing assembly for a disc drive, the E-block having a central bore having a pair of alignment edges to pressingly engage a cartridge bearing of the pivot shaft bearing assembly, and the cartridge bearing supporting a canted coil spring within a peripheral groove so that the spring is interposed between the cartridge bearing and the E-block within the E-block bore. One or more fasteners extend through the wall of the E-block adjacent the alignment edges to pressingly engage the cartridge bearing against the alignment edges, the canted coil spring filling the clearance gap between the cartridge bearing and the E-block bore to provide a resilient support to the E-block.