Abstract: A hydrodynamic bearing unit includes a shaft, a sleeve rotatably disposed over the shaft and defining a plurality of spaced-apart hydrodynamic journal bearings, an annular axial thrust plate secured to the shaft to form a shaft subassembly and having a first radial surface in facing confrontation with a shoulder of the sleeve and defining a first hydrodynamic thrust bearing, a thrust bushing secured to the sleeve to form a sleeve subassembly and having a bearing surface in overlying facing engagement with a second radial surface of the annular axial thrust plate to form a second hydrodynamic thrust bearing, a seal for hydrodynamic lubricant defined within an annular Vee groove located adjacent to the shaft and having an apex converging toward the second hydrodynamic thrust bearing, a motor for rotating the sleeve subassembly relative to the shaft subassembly, and hydrodynamic lubricant within the annular Vee groove, the lubricant being retained in place by capillary force in the absence, of rotation, and by c

Abstract: A class IV partial response, maximum likelihood data channel for a disk drive includes an encoder connected to a data sequencer for converting user data blocks into a predetermined 8/9ths code such as a (0,4,4,) code. A precoder conveys the 8/9ths code into class IV code. An analog write driver supplies the class IV code to a data transducer head during data write-to-disk operations. A read channel connected to the head amplifies and conditions analog signals during data read operations. A quantizer produces samples of the analog signals in accordance with a quantization clock generated by a clock generator. An adaptive FIR filter means is conditions the data samples in accordance with selectable, adaptive filter coefficients. A Viterbi detector puts out the class IV code from the filtered and quantized samples. A postcoder conveys the detected class IV code into detected 8/9ths code. A decoder converts the detected 8/9ths code into user data and supplies user data to the sequencer.

Abstract: A thin film magnetic head, and process for making the same, features a thin film magnetic transducer formed from multiple layers of film and having a magnetic yoke interacting with an electrical coil. The yoke has multiple magnetic flux circuits, deposited on multiple layers of film, encircling the center of the transducer and connected together by proximal and distal vias. A coil has multiple turns intertwined with the yoke, passing between the distal and proximal vias so that the distal vias are exterior to the coil and the proximal vias are interior to the coil, to provide at least four magnetic flux interactions between the coil and the yoke. In preferred embodiments at least one layer of the film is deposited with at least two pole pieces having different easy axis orientations.

Abstract: A method and apparatus for constraining lateral motion of a tape streaming across the transducing face of a magnetic head including two spaced apart reference mechanisms and an adjustment mechanism located in between the two reference mechanisms. Each of the reference mechanisms has a surface for engagement with a first longitudinal tape edge where both surfaces are plannarly aligned with a predetermined tape travel path and mounted for movement with the first tape edge to guide the first tape edge along the tape travel path. The adjust mechanism has a surface for engagement with the second longitudinal tape edge. The plane of the adjustment surface is parallel to the plane of the reference surfaces and mounted for movement with the second tape edge.

Abstract: A self-replenishing hydrodynamic bearing unit comprises a shaft and housing defining an opening for receiving the shaft for relative unidirectional rotation. A plurality of reservoirs contain a lubricating fluid. A hydrodynamic bearing region lies between the plurality of reservoirs for providing a rotational journal for relative rotation between the shaft and the housing. At least one of the shaft and the housing defines a continuous pattern of herringbone or Vee-shaped pumping grooves or passages which communicate between the plurality of reservoirs for pumping the lubricating fluid during relative rotation. The groove pumping creates a pressurized hydrodynamic bearing lubricant film at the bearing region with each groove generating localized unidirectional directional flow of lubricating liquid between the reservoirs along a predetermined axial direction of rotation, wherein some passages create axial flow in a forward direction and the others create axial flow in a reverse direction.

Abstract: In a disk storage device, a method and apparatus for correcting a "runout" error by adding to the servo control signal a sinusoidal signal of amplitude and phase derived to cancel the runout error.

Abstract: A fault detection arrangement provides error detection and verification of generated address sequences for the execution of read/write operations in a storage subsystem. The arrangement also prevents corruption of data stored on the subsystem array module. Gray code counters located in the address path of the array module generate sequential addresses and associated parity for words of a block of data, based on a starting address received from a storage controller. As each address is generated and transferred to storage devices of the array, a parity checker regenerates parity information associated with the transferred address and compares that parity information to the parity information received from the counters. If an address error is detected, execution of the read/write operation is suppressed and the controller is immediately notified of the error.

Abstract: A micro-Winchester disk drive subsystem includes a data block sequencer, cache memory and interface for a host computing machine. The drive includes a base and a plurality of non-removable directly rotated disks forming data storage surfaces. A balanced rotary head transducer actuator is mounted to the base for a plurality of data transducer heads among a multiplicity of concentric data tracks formed on each data storage surface of each of the disks. The track following servo system includes a position encoder coupled between the actuator structure and the base, prerecorded data track centerline information at a radially outermost region and at a radially innermost region of each data surface, and a temperature sensor for sensing temperature of the base at the vicinity of the position encoder.