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 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: 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: 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 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: 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 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: A data capture circuit includes a character detection circuit and a word detection circuit. The character detection circuit determines values for characters represented by a signal having a frequency. In making such determinations, the values for characters are based on an accumulation of differential samples of the signal. The word detection circuit is coupled to receive the values for characters from the character detection circuit. The word detection circuit determines a word value based on the received values for characters. The word detection circuit includes a comparison circuit and an accumulator. The comparison circuit compares a value for a character in a word to a to a value for at least one other character in the word and provides a character value based on the comparison. The accumulator has an input coupled to receive character values from the comparison circuit and an output to provide a summation of character values received by the accumulator.

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.

Abstract: A data symbol sequence detector for choosing data symbol sequences likely to be represented by corresponding sequences of samples received by the detector with these sample sequences formed by sampling data signals obtained from magnetically stored data through a data retrieval channel which asymmetrically affects the magnitudes of the data signals. An expected sample value estimator provides estimated expected magnitude values for a selected set of samples in the sequence, and a magnitude difference determiner is used for obtaining representations of differences between values of the samples in the sequence and the corresponding estimated expected values. These differences representations can be limited in algebraic form.

Abstract: A fiber rolling mechanism is provided to rotate a single optical fiber along its axis so as to align markers placed in the fiber to other fiber's relative markers.

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 magneto-optical (MO) data storage system has a flying optical head supported over a MO storage medium, the flying head having channels or grooves formed therein and optical elements disposed within the grooves for directing an incident light beam to the storage medium and for receiving a reflected light beam from the storage medium. The flying head may comprise a two-piece assembly comprising a slider body which flies over the surface of the storage medium, and a separate optics mounting block formed to receive the optical elements and to be supported on the flying head. Preferably, the slider body is L-shaped and provides an angled surface for receiving a micro-machined mirror aligned with optical elements on the optics mounting block and controllable for deflecting the light beam to and from the storage medium.