Abstract: An information storage apparatus is disclosed for reading and/or writing information on a rigid disk, which includes a non-Newtonian liquid bearing interface between a transducer and a storage medium, instead of a conventional air or Newtonian liquid bearing. The non-Newtonian liquid has a composition which exhibits plastic or pseudoplastic flow at high rates of shear. Preferably, the liquid is of the class of compounds whose viscosity shows a negative dependence on shear rate. Thus, as the relative speed of the transducer and the storage medium increases, while their relative spacing decreases, the increasing shear rate to which the liquid bearing is subjected causes the viscosity of the liquid to reduce. Resultantly, very low flying heights can be achieved, which increases the potential storage density on the storage medium, while the reduced drag exerted on the transducer by the lowered viscosity greatly reduces the power required to rotate the medium.

Abstract: The disk drive system includes an actuator, responsive to an adjustment value, for adjusting the position of a data head with respect to data tracks located on the surface of a disk, and a controller coupled to the data head and to the actuator. The controller receives servo information read from the surface of the disk by the data head. In turn, the controller determines an adjustment value to be applied to the actuator. The adjustment value is calculated dependent on a predetermined variable gain factor. Where the controller determines the position of the heat is oscillating about the center line of a predetermined data track at a frequenc above a predetermined frequency, the controller reduces the gain factor applied in determining the adjustment value.

Abstract: A method of centering a disk on the rotational axis of a motor, the motor having a hub protruding into a center hole in the disk, and the disk having an outer diameter and an inner diameter, is provided. The method includes the steps of (a) placing a contact element in contact with the outer diameter of the disk; (b) applying a damping force and a spring force to said contact element, said damping force and said spring force, urging said contact element towards said rotational axis, wherein the magnitude of said damping force is greater than the magnitude of said spring force, and said spring force is of insufficient amplitude to move said disk with respect to said hub; and (c) rotating said contact element to rotate said disk. Also provided is an apparatus for centering a disk on the rotational axis of a motor having a hub protruding into a center hole of the disk, the disk being loosely fixed to the hub and having an outer diameter and an inner diameter defining the center hole.

Abstract: An actuator for positioning a head with respect to a disk rotatably supported by a base plate in a disk drive assembly, including an actuator arm mounted on the base plate for supporting the head, and an electromagnetic assembly including the base plate for positioning the head with respect to the disk. The electromagnetic assembly includes a first magnet for providing a first magnetic field, the actuator arm includes a coil for passing an electric current in the magnetic field, and the base plate functions as a portion of a return for the magnetic field. A top plate mounted on the base plate supports a second magnet, which provides a second magnetic field, and the coil has portions in the first and second magnetic fields. A center pole extending through the coil, supports for holding the center pole between the top and base plates, and the top and base plates function as returns for the first and second magnetic fields.

Abstract: A disk drive assembly which is resistant to physical shocks and thermally caused distortion, including an end plate, a casing attached to the end plate, and a base plate enclosed in the casing and mounted to the end plate. The base plate supports a rotatably disk and an actuator assembly for reading information from and recording information on the disk. The end plate and the casing form a seal to provide a controlled environment within the casing and the base plate is attached to the end plate in the controlled environment.

Abstract: A two and one half inch form factor disk drive has a base and cover formed of molded plastic and engaged with each other by snap-fit connectors. The cover is molded from a plastic which is more flexible than that used for the base so that the cover complies to the base when the cover and base are engaged. Mounting brackets attached to the cover support a printed circuit board on the opposite side of the base from the cover. The two and one half inch form factor is established by providing the disk drive with a length equal to the width of a 31/2 inch disk drive and a width equal to half of the length of a 31/2 inch disk drive. The disk drive includes a disk having a diameter of approximately 2.6 inches (65 mm) and weighs approximately 5 ounces. A closed-loop, embedded servo tracking system provides a large storage capacity relative to the area of storage media available.

Abstract: A parking device for parking the actuator and the heads in a disk drive utilizes the magnetic field provided by the magnet in the actuator. A permeable latch return provided in the magnetic field creates an attractive force which biases the parking device to a latched position. A coil, provided on the parking device, passes an electric current in the magnetic field provided by the actuator to create a force which releases the parking device.

Abstract: A disk drive assembly which is resistant to physical shocks and thermally caused distortion, including an end plate, a casing attached to the end plate, and a base plate enclosed in the casing and mounted to the end plate. The end plate supports a rotatable disk and an actuator assembly for reading information from and recording information on the disk. The end plate and the casing form a seal to provide a controlled environment within the casing and the base plate is attached to the end plate in the controlled environment.

Abstract: The control system manages the storage and retrieval of data with respect to a rotating media, wherein an actuator is utilized in the selection of data for storage and retrieval. The control system includes a low level media control circuit that permits the selection of the rotational position of the rotating media and an actuator control circuit that permits the selection of the position of the actuator with respect to the rotating media. A system controller is utilized to direct the operation of the low level media and actuator control circuits whereby the system controller specifies and adjusts, in real time, the incremental selection of the rotational position of the rotating media and the position of the actuator with respect to the rotating media.

Abstract: A disk drive control architecture provides for the storage and retrieval of data with respect to a rotating media and for the transfer of data with respect to a host in response to host commands. The control architecture provides for the execution of a plurality of background processes for controlling the spin speed of the rotating media, controlling the positioning of the sensor and controlling the reading and writing of data with respect to the rotating media. The control architecture further provides for foreground processes for controlling the background processes. The foreground processes include an interface task, for coordinating the background processes in the execution of host commands and a monitor task integral to the interface task such that the monitor task is capable of implementing diagnostic commands capable of accessing all of the resources of the control architecture.

Abstract: A low height disk drive having an overall height of one inch (1") or less for a drive having a 31/2 inch format. The drive includes a sloped base plate having support surfaces lying in a first plane. A rotatable disk lying in a plane substantially parallel to a first plane and an actuator assembly for positioning a head with respect to the disk are provided on the top of the base plate. A cover is attached to the top of the base plate to maintain the disk and the actuator assembly in a controlled environment. A printed circuit assembly for controlling the disk drive is attached to the bottom of the base plate, and a header passes electrical signals from the printed circuit board to the controlled environment between the base plate and the cover. Within the controlled environment a reverse flex circuit interconnects the header with the actuator assembly and the heads.

Abstract: An under-the-hub spin motor for a disk drive includes a stabilizer for supporting the outer diameter of the stator to stiffen the base of the spin motor. Stiffening the base in the region surrounding the shaft of the motor increases the resonant frequency of the spin motor, increasing the tolerance of the spin motor to applied vibrations. The stabilizer may be a ring formed integrally with the base plate of the disk drive or the mounting flange of the motor.

Abstract: A method of centering a disk on a disk drive motor with respect to the rotational axis of the motor and/or for balancing the disk to reduce operating vibration of the disk and motor assembly. The centering/balancing method is performed by placing a contact element in contact with the outer diameter of the disk and moving the contact element towards the rotational axis of the motor until the inner diameter of the disk contacts a portion of the hub of the motor which protrudes into the center hole of the disk. Then, the disk is rotated while the contact element is simultaneously moved away from the rotational axis of the motor at a rate related to the rotational speed of the disk.

Abstract: Control and synchronization of a polyphase, brushless DC motor (used for a hard-disk system) during initial start-up of the motor, is effected by monitoring rotor position using a high-frequency commutation: A short current pulse is applied to each power phase of the motor, and motor current conducted in response thereto, is measured to determine therefrom positional information of the rotor. From such positional information the identity of the appropriate motor phase to which is applied a torque-producing current is determined. Cycles of high-frequency commutation and application of torque-producing are performed, until the rotational speed of the rotor has attained a predetermined RPM.