Abstract: Momentary contact with a defect site of a data storage disk or free particle by a magnetoresistive read element of a flying head causes momentary heating and unwanted increase in element resistance (thermal asperity) which can disrupt hard disk drive data reading operations. Since the disk carries a predetermined data format, the disk drive controller correlates location of a thermal asperity to the format and thereupon selects from several available thermal asperity recovery methods a method most likely to minimize thermal asperity effect upon disk drive operation during rereading of data at the thermal asperity location.

Abstract: A mass storage device includes a secondary bidirectional interface digital port connected to an embedded microcontroller, and a wireless communications path, such as an optical infra-red (IR) path, connected to the secondary bidirectional interface port for providing a wireless bidirectional secondary communications path between the embedded microcontroller and an external service unit which is not directly connected to the digital computer via a primary electrical bus structure.

Abstract: A power-reduced digital control within a feedback control loop of a sampling data detection channel controls a predetermined operating parameter of the channel in which an analog to digital converter provides digital samples of information in the channel at a predetermined channel clock rate. The digital control comprises a parameter error extraction circuit clocked at the predetermined channel rate which is connected to receive digital samples from the analog to digital converter, and which extracts parameter error values from the digital samples; an averaging circuit for averaging the extracted parameter error values over an integral submultiple of the predetermined channel clock rate; and a parameter error processing circuit which is connected to the parameter error extraction circuit and clocked at the integral submultiple of the predetermined channel rate for generating and putting out digital control values within the feedback control loop for controlling the predetermined operating parameter.

Abstract: Media unit access time within a media library is minimized by revectoring an address of a closest available media unit player to match a logical address of a media unit player specified within a media exchange command received from a host commanding the library to move a media unit from a command-specified slot location holding a media unit desired by a host computer to the command-specified media player logical address.

Abstract: A self-contained hydrodynamic bearing unit with improved sealing and performance is disclosed. Centrifugal capillary seals are angularly defined between an outwardly tapered outer surface of a top screw and an inwardly tapered inner surface of an annular clamp ring at the top of the bearing unit as well as between an outwardly tapered outer surface of a seal plate and an inwardly tapered inner surface of an annular clamp ring at the bottom of the bearing unit. During operation, bearing lubricant is pumped away from the seal opening and toward the bearings by centrifugal force at the seals, providing dynamic sealing. When the bearing unit is not rotating, capillary forces retain the lubricant within the seal, preventing the lubricant from leaking. The tapered configuration of the seals also shortens the vertical seal length for a given effective seal length, thereby maximizing the journal bearing length/span and improving dynamic performance of the bearing unit.

Abstract: A deflection mirror tower (DMT) of a multiple-disk array, optical storage system includes a plurality of prism members, each having an angular mirror surface, arranged along a vertical axis of the DMT and configured at a predetermined angular orientation to deflect a laser beam to a respective disk surface. The DMT is generally fabricated using a two-level partitioning process. Several prepared glass substrates, i.e., one for each mirror type, are initially sliced into bars having predetermined geometries. A bar from each substrate is sequentially aligned to a master reference and bonded to adjacent bars to form an intermediate bar stack. The stack is then segmented into a plurality of DMT components, each having a plurality of prism members.

Abstract: A read-after-write head for four channel azimuth recording in one mode of operation and two channel non-azimuth recording in another mode of operation. Four forward write head gaps, four read head gaps, and four backward write head gaps are geometrically positioned within a rotatable and laterally indexable face plate of a recording head housing. The read and write heads gaps collectively provide four forward write channels, four read channels, and four backward write channels. During the azimuth mode of operation, the head is rotated to the preselected positive or negative azimuth angle and all of the read and write channels are utilized. During the non-azimuth, or vertical, mode of operation, write channels two and four are utilized in combination with read channels one and three to provide two-channel non-azimuth, or vertical, operation.

Abstract: A magnetic disk drive data storage disk defines recording tracks divided into data sectors by narrow servo spokes. A data sector lying between servo spokes is recorded with user data encoded in accordance with a code having a predetermined distance and user data code rate. Each servo spoke of the recording area has at least one servo information field encoded in a wide bi-phase code pattern. The disk drive further includes a synchronous sampling data detection channel having a data transducer head positioned by a servo-controlled actuator over the recording track, a preamplifier for receiving electrical analog signals magnetically induced by the data transducer head from flux transitions present in at least the servo information field, a digital sampler for synchronously sampling the electrical analog signals to produce digital samples, and wide bi-phase decoding circuitry coupled to receive digital samples from the synchronous sampling data detection channel for decoding the wide bi-phase code pattern.

Abstract: A method of writing data onto a magnetic tape storage medium in the form of data blocks and error correction code blocks. Data is received from a data source and formatted into data and error correction code blocks. Data entities are created from the data and error correction code blocks. Data envelopes are defined to include one or more such data entities. The data envelopes are sequentially written onto the magnetic tape medium. The data and error correction blocks within the data envelopes may be arranged in any order without regard to the physical channel or positional placement. Blocks containing user data and those containing internally generated error recovery information are freely intermixed with random duplications allowed. Block placement topology heuristics can be freely applied within envelopes, and are typically driven by error handling considerations. Block write errors are repeated and migrated into other data channels as necessary.

Abstract: A method is provided for elimination of periodic inter symbol interference (ISI) resulting in timing phase steps and channel amplitude control steps occurring following a periodic preamble pattern, such as a 1/4T sine wave pattern and at the beginning of a random pattern user data field in a partial response, maximum likelihood digital magnetic data storage channel. The method comprises the steps of:determining a periodicity of periodic ISI events in relation to main magnetic flux transitions during playback of a periodic signal waveform thereof,writing a new preamble field to the magnetic data storage channel of a periodic signal waveform preceding the user data field in which the phase of the periodic signal waveform is shifted, e.g.

Abstract: A voice coil motor (VCM) driver has four field effect transistors connected to a motor coil as an H-bridge. A sense resistor in series with the coil and the H-bridge senses coil current. A feedback amplifier provides a feedback signal from a voltage developed across the sense resistor. A summing junction sums current command signals with the feedback signal. A transconductance loop compensation amplifier has an inverting input connected to the summing junction, has a non-inverting input connected to a reference level, and has an output control signal node. The control level is connected to control linear transconductance differential driver amplifiers including the four field effect transistors during a linear drive mode.

Abstract: A deflection mirror tower (DMT) of a multiple-disk array, optical storage system includes a plurality of prism members, each having an angular mirror surface, arranged along a vertical axis of the DMT and configured at a predetermined angular orientation to deflect a laser beam to a respective disk surface. The DMT is generally fabricated using a two-level partitioning process. Several prepared glass substrates, i.e., one for each mirror type, are initially sliced into bars having predetermined geometries. A bar from each substrate is sequentially aligned to a master reference and bonded to adjacent bars to form an intermediate bar stack. The stack is then segmented into a plurality of DMT components, each having a plurality of prism members.

Abstract: An analog-to-digital converter circuit in a sampling data detection channel of a disk drive synchronously samples user data in the data track areas at a first quantization resolution and samples servo bursts from the spoke areas at a second quantization resolution effectively greater than said first quantization resolution. An offset circuit provides a predetermined analog offset signal to a combining circuit which combines it with an incoming analog signal to provide a composite signal during a spoke servo burst sampling interval. An analog-to-digital converter samples the composite signal during the servo spoke burst sampling interval, and synchronously samples the analog signal during a user data sampling interval. A digital averaging circuit averages the servo spoke samples over a predetermined averaging interval to provide averaged burst samples having increased bit resolution.

Abstract: A low stiffness apparatus supporting a read/write transducer head slider for reduced pitch and roll bias in flying conditions. The apparatus comprises an actuator arm, a load beam, and a flexure in combination. The flexure is comprised of an outer portion, an inner portion, and a bight portion. The bight portion connects the inner portion to the outer portion and provides a one step double bend resulting in a spaced relation between the inner and outer portions along the z-axis. The inner portion also has a dimple formed therein for pivoting against the load beam and is located substantially near the bight. The low stiffness is created from the bight portion and the location of the dimple. The apparatus also prevents the problem of wire overhang, where the wire crashes onto the disc during flying conditions. The apparatus furthermore permits the transducer head slider to move more closely to the hub of the disc, thus allowing the system to read more data.

Abstract: A head suspension has a segmented trace conductor array for electrically interconnecting a read/write head to electronic circuitry in a disk drive. Each trace segment has a predetermined generally rectangular cross-sectional area such that the intermediate first segment has a predetermined cross-sectional width greater than a predetermined cross-sectional width of an first outer segment, in order to optimize current density at very high signaling frequencies associated with information transfer between the head and the read/write circuitry.

Abstract: According to the invention, a data integrity code including logical block address ("LBA") and circuit implementation are provided. The code and implementing circuitry are utilized to enable data block LBA verification during a block transfer and retrieval process. The preferred data integrity code has embedded LBA information and also serves as a crosscheck code used to detect miscorrection by an error correction code ("ECC"). In a preferred disk drive embodiment, data integrity block ("DIB") is provided to verify that the LBA value associated with a given data block in a host interface matches the value associated with that same data block in a buffer memory and in a data sequencer. In a preferred method of use, data integrity/cross-check redundancy with LBA is appended to data blocks transmitted to a buffer memory and verified after the data block has been transferred from the buffer.

Abstract: A tape drive reel for providing controlled, uniform stacking of tape during read/write operations to reduce lateral tape motion. The reel comprises a hub and two flanges that are located on opposite sides of the hub. Each flange includes a deflectable radial section which pivots about the hub as tape is wound onto the reel. As each loop of tape is wound on the hub and the amount of tape stacked thereon increases, the radial sections of the flanges are deflected towards each other and against the opposite edges of the tape stack, ensuring that the tape stacks uniformly.

Abstract: A switch mode sine wave driver circuit selectively sources and sinks driving currents to and from a DC brushless motor in accordance with the substantially sinusoidal switched driving signals. A signal waveform monitoring circuit monitors electrical signals appearing the motor windings and puts out motor phase reference signals. A phase clock generator provides a motor-synchronized clock signal. A phase counter is clocked by the motor clock signal and is reset by the motor phase reference signals. The phase counter counts predetermined phase intervals and generates phase counts and phase polarity signals. A motor state decoder responds to the phase polarity signals by generating state control signals. Sine wave logic circuitry is addressed by the phase counts and puts out digital polyphase sine values for each one of the polyphases. A polyphase pulse width modulator circuit responds to the polyphase sine values by generating phase pulses having duty cycle duration controlled by the sine values.

Abstract: A head suspension has an integrated multi-layer trace conductor array for supporting and electrically interconnecting a read/write head to electronic circuitry in a disk drive. The trace conductor array includes an integrally formed electrical shield which may be grounded or ungrounded and formed to have a depth greater than a skin effect depth at a frequency of an interfering wave front.

Abstract: In a disk drive using a write-wide inductive write element and a read-narrow magneto-resistive read element within a head transducer assembly for writing and reading magnetic patterns on a rotating magnetic storage disk in a plurality of concentric tracks, a track pattern formed in each concentric track includes embedded servo wedges wherein each wedge includes a servo position portion which is offset from a centerline of both the servo sector and a following user data sector by an amount related to offset between the inductive write and magneto-resistive elements of the head transducer assembly. Furthermore, the servo sector contains four servo bursts. The servo bursts are arranged such that each sequential burst is offset from a previous burst by a fractional offset increment. The fractional offset increment is typically one-third of a track pitch.