Abstract:
A disk drive including firmware for overcoming stiction and breaking free the heads of a disk drive which may adhere to the disk surface when the disk is at rest. Upon start-up of the disk drive, if stiction at the head/disk interface occurs, the voltage to the spindle motor and/or actuator motor may be rapidly fluctuated so as to cause a pulsing of the spindle motor and/or actuator motor. Pulsing both the spindle motor and actuator motor creates forces in a plurality of radial directions to allow the head(s) to break free from the disk(s) in the direction of least resistance. Moreover, as the resonant frequency of the spindle motor varies depending on the number of heads that are stuck, the firmware pulses over a range of frequencies including the various resonant frequencies of the spindle motor corresponding to various numbers of heads stuck.
Abstract:
A disk drive, comprising a storage medium having data tracks for storing data, a spindle motor mounting the storage medium for rotation, an interactive element for reading information from and writing information on the data tracks of the storage medium and an actuator responsive to control signals, mounting the interactive element for motion to selectively position the interactive element relative to preselected data tracks of the storage medium and to move the interactive element from a first data track to a second data track in response to the control signals. The interactive element is arranged and configured to fly above the storage medium. Moreover, control electronics are coupled to the actuator for generating the control signals to cause the actuator to move the interactive element from the first data track to the second data track. The control signals include velocity control signals generated as a function of the number of data tracks to be crossed from the first data track to the second data track, and the location of the first data track relative to the second data track. The velocity control signals control the actuator to move at preselected velocities, including a maximum velocity.
Abstract:
A method is shown for testing a magnetic disk to be used in a disk drive. The method includes the steps of measuring a height profile of an outer radial edge of the disk (22), using the profile to determine a slope value for each of a pair of radial segments (54) of the disk, calculating a difference value between the slope values of the pair, comparing the difference value to a preselected threshold difference value and indicating when the difference value is equal to or less than the threshold difference value. The threshold value indicates an outer most diameter of the disk where fly height operation for a head (46, 48) is still stable.
Abstract:
An apparatus that compensates for the asymmetry and the baseline shift in the signal generated by a magnetoresistive head. The apparatus stores a first correction factor for the baseline shift, a second correction factor for correcting the amplitude of positive portion of the signal and a third correction factor for correcting the amplitude of negative portion of the signal. The first correction factor for correcting for baseline shift is added to the signal generated by the magnetoresistive head to generate a baseline corrected signal. The baseline corrected signal is then monitored for positive and negative excursion from the baseline and the positive excursions are multiplied by the second correction factor and the negative excursions are multiplied by the third correction factor for generating a compensated signal.
Abstract:
A speed control system is disclosed wherein a brushless DC motor and a magneto resistive encoder are able to rotate a motor at arbitrarily low speeds. The motor is able to rotate at low speeds by having a filtered signal generated by an encoder applied to its inputs. The encoder is coupled to a series of filters which remove DC level and harmonic distortions from the resulting encoder signal. These filtered signals are then applied to the motor to control motor rotation speed.
Abstract:
In liquid disk drives, liquid bearing materials based on hydrocarbon liquids, halogenated liquids and mixtures thereof are used at the head-disk interface. Additives such as antioxidants and boundary layer lubricants may be incorporated to enhance oxidative stability and lubricity. The liquid bearing materials have relatively low viscosities and non-Newtonian flow characteristics so as to reduce drag at the read/write head compared with Newtonian liquid bearing materials.
Abstract:
A structure for supporting an array of three electrically connected disk drives (22a, 22b) in a full-height drive bay (23) of a personal computer. The drives have a form factor of 3.5", including a height of approximately 1.0". The array is supported within a substantially cubical cage (20), slightly spaced from each other within the cage so that they are supported on 1.05" centers. The support structure further includes a plurality of disk carriers (44) attached around at least two sides of each of the disk drives to support and properly position the drives within the cage. The disk carriers may be custom fit to any drive design. Thus, subject to the proper size requirement, a wide variety of drives may be utilized within the cage of the present invention.
Abstract:
A multi-channel rotary transformer (300) including a stator (320) having winding elements (333, 336, 334, 335), and a rotor (310) mounted for rotation about a rotational axis and having a plurality of sector-shaped blades (311-318) each of which including one of a plurality of windings (321-328), wherein the rotor is rotationally positionable relative to the stator such that only one winding of the rotor interacts with one of the winding elements of the stator at a given time.
Abstract:
A two and one-half inch form factor disk drive comprises a base (42), a cover (44) attached to the base (42), and at least three storage disks (48a-c) in a height of about three-quarters of one inch. The disk drive includes read/write heads attached at the end of head suspension (114a) for reading and writing information to the disks (48a-c). Actuator assembly (52) selectively positions the heads with respect to the disks (48a-c). Control circuitry (34) is mounted on a printed circuit board (58) which is adjacent to the bottom of the base (42) for controlling the actuator assembly (52) and the read/write heads.
Abstract:
A disk drive system for use with a host processor where the host processor employs either a look ahead command set or a tag queuing command set for communicating with the disk drive system. The disk drive system comprises a first storage means for storing an optimized look ahead operating system and an optimized tag queuing operating system; a first means connected to the first storage means for initially retrieving one of the operating systems stored in the first storage means; a second storage means for storing the initial operating system retrieved by the first means; a second means for detecting the condition that a command issued by the host processor is associated with the operating system that was not initially retrieved by the first means and stored in the second means; and a third means for responding to the second means detecting the condition by retrieving the operating system that was not initially retrieved by the second means from the first storage means, for storing the newly retrieved operating system in the second storage means in place of the initially stored operating system and for transferring control to the newly stored operating system.