Abstract: A task assigning system within a dual actuator disk drive system wherein each task has a cylinder address comprising a plurality of registers, each register having a unique address and a plurality of fields for storing a task including the cylinder address associated with the tasks, a queue comprising a header register, the header register having a plurality of fields, an insertion means for inserting and ordering the registers into the queue when a task is first stored into the register, a first means for assigning tasks stored in the queue to a first actuator of the dual actuators in the sequence of increasing value of the cylinder addresses of tasks stored in the registers in the queue and a second means for assigning tasks stored in the queue to a second actuator of the dual actuators in the sequence of decreasing values of the cylinder addresses of the tasks stored in the registers in the queue.

Abstract: A two and one half inch form factor single disk drive has a height of 0.60. The spin motor is mounted in a recess in a housing base to reduce height of the housing. A printed circuit board is mounted to the base with all components of the circuit board being mounted on one side of the board opposite from the base. The cover and base are preferably made of cast aluminum alloy with the cover being convex configured for added strength.

Abstract: A series of longitudinal tape movement and lateral tape head movement operations are performed to collect data by which the physical format or cartridge type and also the magnetic format are simultaneously determined. The tape format detection system works during the load point seeking sequence and it is therefore able to determine the tape format type while the tape head is being positioned for use. Both longitudinally spaced and laterally spaced format identification fingerprints can be detected and analyzed.

Abstract: An information storage apparatus is disclosed for reading and/or writing information on a rigid storage medium which includes a liquid bearing interface between the transducer and medium instead of a conventional air bearing. The liquid is a fluorocarbon which has stable, self-lubricating, viscous and high-density properties. In an exemplary embodiment of a cockpit voice recorder/flight data recorder, low-density metallic components or composite parts of the rigid magnetic disk drive assembly with essentially the same density as the liquid achieve a near zero buoyancy configuration that obviates the effects of vibration and acceleration.

Abstract: A method for testing rolling contact bearings, where each bearing has an inner race and an outer race. The method comprises: coupling the outer race of the bearing to a strain gauge; rotating the inner race of the bearing in a first direction and measuring the torque exerted on the outer race; and rotating the inner race of the bearing in a second direction and measuring the torque exerted on the outer race. In another aspect, the invention comprises an apparatus for testing bearings. The apparatus includes elements for rotating the inner race of the bearing; a strain gauge; elements for coupling the outer race of the bearing to a strain gauge; and elements, coupled to the strain gauge, for measuring the force applied to the strain gauge when the inner race is rotated.

Abstract: The invention provides a device to facilitate precise positioning of a tape head at a particular track on a magnetic tape. Typically, the magnetic tape is adapted to be received in a drive assembly which has a memory and a motor. The device includes a mounting tray for receiving the tape drive assembly, and a laser beam emitted from a laser source. On the tape head of the device, a reflector is positioned and moves with the tape head. Beam directors are provided to ensure that the laser beam passes from the laser source to the reflector. The distance traveled by the tape head from a predetermined point to a position adjacent a track on the magnetic tape is accurately measured, and the extent of movement of the motor required to move the tape head through such a distance is also measured. Thereafter, the measurements are programmed into the tape drive assembly memory.

Abstract: The invention provides a track format and a record carrier system for supporting a track architecture where a first field, such as a data field, is split by a second field, like a servo field. The preferred track format includes a split count field that contains information on the location of the second field with respect to the first field. In the preferred embodiment, the split count field is located in the header associated with the data field. The present invention also includes circuitry that reads the split count and uses the split count to discriminate the first field from the second field or the information contained in the first field from the information contained in the second field. The invention is particularly useful in modified constant angular velocity (MCAV) magnetic disk systems where constant frequency servo fields are embedded among variable frequency data fields. The present invention is, however, applicable to any kind of record carrier where one field is split by another field.

Abstract: A multiple actuator disk drive utilizes multiple heads, associated with respective ones of multiple actuators, to read data from and write data to all tracks on the surface of a disk. The positioning of each head by the respective actuator is controlled by embedded servo-information recorded in the data tracks. The data tracks have a density of greater than 2000 tracks per inch. Utilizing two actuators provides access times which are reduced with respect to the access times provided by disk drives having a single actuator and an increased data transfer rate.

Abstract: A high level controller for maintaining communication with a host processor via a host processor interface for establishing communication paths between the host processor interface, an internal processor and a plurality of storage means. A first means receives indicia from the internal processor where the indicia specifies one of the communication paths and generates control signals for forming the specific communication path requested. A second means receives the control signals from the first means and forms the requested communication path. A third means is connected to the first and second means for controlling the communication of the system with the host processor interface in accordance with control signals generated by the first means. In this manner various data paths for communication between the host interface, internal processor and a plurality of storage means may be adaptably specified and formed to make optimum use of the system.

Abstract: A low noise spin motor for use in a disk drive includes two bearings having different inside diameters, different outside diameters, and preferably the same size balls. The balls in the larger bearing travel at a faster speed thereby increasing the noise frequencies and resonant frequency as compared to the smaller frequency whereby the noise from the two bearings is not compounded. A small and compact disk drive using the spin motor is described.

Abstract: A retainer assembly (10) comprises a retainer member (24) and a spring (36). The spring (36) works in combination with a conical surface (34) on the hub (12) and a conical surface (28) on the retainer member (24). Depending upon magnitudes of defined angles A and W, the assembly (10) resists any axial force (42) that may act to disengage the disk (14) from the hub (12). The angles A and W are variable so long as a coefficient of friction .mu. between the conical surface (34) or the conical surface (28) and the ring (36) is greater than the tangent of one half the angle W.

Abstract: A disk drive architecture controls the transfer of data between a host processor interface and a recording media that includes one or more disk surfaces for storing data. A low-level data controller controls the transfer of data between the disk surfaces and a data buffer. An interface controller controls the transfer of data between the host interface and the data buffer. An arbiter and buffer controller, responsive to data transfer requests from the low-level and interface controllers, arbitrates data storage and retrieval accesses of the data buffer. The low-level and interface controllers operate substantially independent of one another in performing their respective control operations. Consequently, data is transferred bi-directionally through the data buffer at the optimum timing for both controllers.

Abstract: A disk drive apparatus is disclosed for primary use with portable, laptop or other information storage systems. The disk drive apparatus includes one or more about 2.5 inch hard disks. A rotary actuator is utilized and includes an arm assembly having a cam follower member for use in dynamically loading/unloading read/write head(s). The cam follower member moves along a ramp, which forms a cam surface, for loading/unloading. The spin motor assembly of the disk drive apparatus includes rotor having a clamp ring that enables a more powerful spin motor to be incorporated, as well as facilitating and enhancing the connection of the hard disks to the spin motor. The disk drive apparatus also includes servo electronics responsive to a back emf generated signal for use in the servo operation, which use has the potential to increase the servo bandwidth.

Abstract: A multiple actuator disk drive utilizes multiple heads, associated with respective ones of multiple actuators, to read data from and write data to all tracks on the surface of a disk. The positioning of each head by the respective actuators is controlled by embedded servo-information recorded in the data tracks. The data tracks have a density of greater than 2000 tracks per inch. Utilizing two actuators provides access times which are reduced with respect to the access times provided by disk drives having a single actuator and an increased data transfer rate.

Abstract: A latch mechanism for locking an actuator arm in a disk drive includes a latch pivotably supported in the disk drive for engaging the actuator arm and an electromagnet for capturing and holding the latch to disengage the latch from the actuator arm. A spring is provided to bias the latch to engage with the actuator arm. A swivel plate is provided on the actuator arm and the electromagnet captures the swivel plate; in particular, the electromagnet has two poles and the swivel plate contacts one of the poles and an air gap exists between the swivel plate and the other pole. The air gap allows the electromagnet to release the swivel plate. The swivelling action of the swivel plate causes the swivel plate to seat with the entire surface of the one pole of the electromagnet, increasing the ability of the electromagnet to hold the swivel plate once the swivel plate has been captured.

Abstract: A spindle motor for two and one-half inch disks and three and one-half inch disks has a disk mounting surface with a horizontal tolerance of less than 30 micro inch to prevent warpage of a disk mounted thereon by pressure engagement. The disk mounting surface is machined to the requisite tolerance by mounting an assembled motor on a support surface of a rigid granite block table and spinning the rotor of the motor by an external drive. A cutting tool then machines the disk mounting surface.

Abstract: A magnetic parking device for a disk drive includes a magnet and a member for containing the magnetic field produced by the magnet. The magnetic field containing member has an air gap which is substantially parallel to the magnet flux lines of the magnetic field so that there is no fringing of the magnetic field outside of the gap. The device magnetically captures a magnetically permeable capture member provided on the actuator of a disk drive without contacting the capture member and only when the actuator enters the gap in the magnetic field containing member.

Abstract: An under-the-hub spin motor for a disk drive includes a shaft having a first portion mounted to a support member an a second portion shaft having first and second bearings provided at the first and second ends thereof. A hub is supported by the first and second bearings and a disk having an inner diameter is mounted on the hub. A stator is provided on the support member so that the stator is outside of the Z-axis region between the bearings and a rotor is provided on the hub so that the rotor is concentric with the stator and so that a gap is defined between the stator and the rotor. The gap has a radius larger than the inner diameter of the disk.

Abstract: A bipolar magnet as used in magnetic disk drives is characterized by measuring field strength of the magnet along a plurality of radii using a Hall effect sensor which is incrementally indexed across the magnet by a stepper motor. The gap field strength, pole transitions, and null zone can be determined from combinations of the measurements along the plurality of radii.

Abstract: The read/write channel is programmatically adaptable to the media used for storing data in response to data signals and the read/write head used to transfer the data signals to and from the media. Adaptability is provided by progammable signal processing elements in the read/write channel. The programmable elements include a read threshold element for determining whether data signals transferred from the media exceed a data discrimination level determined by a first programmable value, and a data window element for determining whether data signals transferred from the media occur within a data signal window whose timing, relative to a data clock signal, is determined by the second programmable value. Additional programmable elements include an amplifier element that is programmed to provide a corresponding level of write current and a precompensation block for providing data signal precompensation.