Abstract: A disk drive rotary actuator has a head arm rotatable about a pillar. The pillar has abutments engaging a rolling member located in a recess in the head arm. The rolling member and pillar provide a space between abutment surfaces through which a flexure plate passes. A spring holds the pillar and arm together with the rolling member between them.

Abstract: A low-profile spindle motor for a disc drive data storage device includes a cylindrical sleeve which is used to mount the motor to a housing base using press-fitting or adhesive bonding, thus eliminating the vertical height required by screws, bolts or other prior art mounting mechanisms. The same cylindrical sleeve is used to mount the stator stack of the motor, and, on the inner surface of the cylindrical sleeve, to mount the ball bearing assemblies used to allow rotation of a central shaft and attached disc-mounting hub. In another aspect of the invention, ball bearing assemblies having a sealing element on only one side are used to allow greater separation between the ball bearing assemblies, while maintaining a low-profile motor. In yet another aspect of the invention, signals to drive the motor are directed to the stator windings via a printed circuit cable whose termination pads are disposed in the vertical space between adjacent stator windings.

Abstract: A head suspension for mounting and supporting the head assembly in a disc drive. The head suspension includes a ramp contact feature located adjacent the leading edge of the head assembly, and the ramp contact feature is in the form of an inclined cylinder with a spherical contact end. The shape of the ramp contact feature allows for simplification of the ramp surface profile and provides the ability to allow for assembly tolerance build-up in multi-disc disc drive assemblies.

Abstract: A multi-task system employs a single interrupt occurring at fixed time intervals to initiate the control functions. The actuator control, servo control and spindle control routines are operated on a priority basis so that if a control function having a high priority is not ready to be executed, the processor immediately performs execution of the next available control function. More particularly, the spindle control process is operated in the foreground with the actuator control and servo control routines operated on an interrupt basis of the spindle control routine. Upon receipt of the interrupt signal, priority is first given to an actuator control routine for execution. Upon completion of the actuator control routine, or if the actuator control is not ready to be executed, access is given to a servo control routine. At the conclusion of the servo control routine, the interrupt exits to the spindle control routine.

Abstract: A method of determining a first sector within a zone on a recording medium. The recording medium has several zones, each zone having several subtracks, each subtrack having several sectors. Each sector has a position identifier field identified as S(M,N) for sector N and subtrack M. The values for each subtrack form a sequence of values with a break in the sequence that is used to mark the first sector.

Abstract: In a peak detection system having a variable gain amplifier (VGA), a counter is initialized and a countdown is triggered. Each time a qualified peak is detected, the counter is re-initialized. If the countdown is completed, the VGA gain is updated. This method can be used to boost amplifier gain that is too low to generate a qualifying threshold, even while overlooking short periods of very low output.

Abstract: A narrow read head and a wider write head are used to store and retrieve data from a storage medium, such as a magnetic disk or tape. The wider write head is selectively positioned to record overlapping data tracks. The read head is subsequently positioned to read the non-overlapping portions of the data tracks. In one format, a read seldom data block is recorded by sequentially recording a plurality of data tracks such that each subsequent data track partially overlaps a previously written data track. In another format, pairs of data tracks are recorded by side-by-side, wherein within each pair of data tracks there is an overlapping region. In either format, the narrower read head is positioned to read the non-overlapping portions of the data tracks. Consequently, the storage capacity of the storage medium is optimized to take advantage of the narrow read head.

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 system for unloading heads from and loading heads into cooperative engagement with discs in a disc drive, including a novel head suspension for mounting and supporting the heads. The head suspension includes a primary ramp contact feature formed as a portion of the load beam portion of the head suspension and a secondary ramp contact feature formed as an extension of the mounting tab of the gimbal portion of the head suspension. The primary ramp contact feature acts as the principal lifting mechanism of the head suspension, while the secondary ramp contact feature serves to controllably lift the head. In an alternative embodiment, only the secondary ramp contact feature is used for the unloading and loading of the head.

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 storage media is provided. The surface of the media is made to vary by an insubstantial amount relative to a datum to provide for improved flyability of a head over the surface.

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: An apparatus that compensates for the asymmetry and the baseline shift in the signal generated by a magnetoresistive head. The apparatus stores a first correction factor for the baseline shift, a second correction factor for correcting the amplitude of the positive portion of the signal and a third correction factor for correcting the amplitude of the negative portion of the signal. The first correction factor for correcting for baseline shift is added to the signal generated by the magnetoresistive head to generate a baseline corrected signal. The baseline corrected signal is then monitored for positive and negative excursions from the baseline and the positive excursions are multiplied by the second correction factor and the negative excursions are multiplied by the third correction factor for generating a compensated signal.

Abstract: A multiple disk drive storage system includes a latch assembly for positively latching a head positioning actuator arm when the head is positioned on a load/unload mechanism at the outer perimeter of the disks. Latching and unlatching cycles of the latch assembly are effected by interaction of the actuator arm motion and a latch arm retention magnet structure. In the latch position, the actuator arm is mechanically captured by a hook shaped latch head at one end of the movable latch arm, so that, even in a power off condition the actuator arm is positively latched by the combination of the actuator arm motion limitations, the latch head shape, the latch arm motion limitations and a bias spring urging the hooked latch head into a permanent, static latch with the actuator arm. The opposite end of the latch arm is provided with a magnetic mass which is attracted and held by the retention magnet.

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 limit stop system for defining the extremes of the range of motion of the actuator of a disc drive. An elongated slot having inner and outer contact surfaces is provided in the bobbin inside the coil of the actuator voice coil motor. A pin member having a compliant portion is assembled through the elongated slot in the coil bobbin and into engagement with stationary components of the disc drive. When the intended extreme of the range of motion of the actuator is reached, either the inner or outer contact surface of the elongated slot contacts the compliant portion of the pin member preventing further motion of the actuator in that direction.

Abstract: An apparatus designed for the testing of a micro-machined mirror that is mounted onto a flying optical head is described. As in the case of normal operation of the head, laser light is coupled into the head using an optical fiber. The light propagates through the head, is emitted from the fiber, reflects off of the steerable mirror inclined at 45 degrees to the fiber axis, and passes through a focusing lens and exits the head. A position sensitive detector (PSD) is placed so as to detect the position of the light spot as it exits the head. Actuation of the mirror's steering capabilities modulates the spot position, which is detected by the PSD and its associated electronics. The profile of the PSD is made small enough to fit in a space between two opposing optical heads on a head stack assembly (HSA) so that the test can be performed immediately prior to the assembly of the disc drive. An array of such PSD's is constructed so that all of heads on an HSA can be tested simultaneously or in a multiplexed manner.