Abstract: A spin motor control system includes a BEMF commutation circuit, a startup circuit and a monitor circuit, each of which operate utilizing digital techniques. The BEMF commutation circuit includes first and second counters that are programmable to accommodate for changing system parameters. The BEMF commutation circuit does not require the incorporation of an external capacitor, is insensitive to leakage current, and provides stable timing characteristics. The startup circuit also includes a counter and is programmable to accommodate for changing system parameters. The startup circuit does not require an external capacitor and provides stable generation of the startup pulses. The monitor circuit includes first and second counters for blanking the BEMF circuitry after commutation. The monitor circuit further includes circuitry for detecting and correcting the direction of rotation of the spin motor.

Abstract: A silent seek servo controller is used in a low profile miniature disk drive to minimize acoustic noise and the problems associated therewith. The silent seek servo controller of this invention reduces acoustic noise generation at the expense of seek performance. Since the silent seek servo controller of this invention minimizes acoustic noise, the controller helps to eliminate vibrations within the computer. The silent seek servo controller is a one mode continuous position servo seek controller that accelerates and decelerates the actuator using a smooth, continuous and completely symmetric acceleration trajectory. Specifically, for a seek time t, the disk drive actuator is accelerated for one-half the seek time, i.e, time t/2, and decelerated for the other half of seek time t. The peak acceleration occurs at time t/4 and the peak deceleration occurs at time 3t/4. The symmetry of each acceleration phase assures that any acoustic noise generated by uneven acceleration is eliminated.

Abstract: A computer having a hard disk drive includes a battery voltage monitor which establishes a shut down condition of the computer if the supply voltage falls below a chosen level V.sub.L. Upon start up of the hard disk drive motor, current through the motor is limited so that supply voltage of the battery to a computer does not fall below level V.sub.1, which level is greater than the level V.sub.L. Additionally during start up, current in the motor is controlled so that voltage supplied by the battery to the computer does not rise above a threshold level V.sub.2 which is greater than V.sub.1.

Abstract: According to the invention, a disk drive includes structure that prevents a non-operational shock from damaging a data region of a disk surface as a result of contact between the data region and other components of the disk drive. The disk drive includes one or more retaining structures, each retaining structure having portions that extend, above and below the disk, respectively, from a location beyond the periphery of the disk to a location within the periphery of the disk, but outside of the data region of the disk surface. The one or more retaining structures limit displacement of the disk in a direction perpendicular to the surface of the disk to prevent the data region from contacting other components of the disk drive, thereby preventing damage to the data region.

Abstract: Disclosed is a disk drive information storage device which includes a disk for recording and reproducing information, with the disk drive information storage device having a housing with a baseplate which includes a peripheral portion having a lip which extends circumferentially around the peripheral portion and the cover also includes a peripheral portion with a free edge at the periphery of the cover such that when the baseplate is engaged with the cover the overlap of the free edge of the baseplate and the free edge of the lip provides shielding to the internal components of the disk drive from electromagnetic interference, which my be present in the environment in which the disk drive is utilized. The disk utilized in the disk drive has a diameter in the range of from about 45 mm to about 50 mm. The housing of the disk drive has a first external dimension of about 51 mm and a second external dimension of about 70 mm.

Abstract: Disclosed is a disk drive information storage device having a housing and a disk means for recording and reproducing information. The disk drive information storage device utilizes a spin motor control system having a start-up control circuit which includes a counter and is programmable to accommodate for changing system parameters. The start-up control circuit does not require an external capacitor and provides stable generation of the start-up pulses. The spin motor control system also includes a BEMF commutation circuit which operates utilizing digital techniques. The BEMF commutation circuit includes first and second counters that are programmable to accommodate for changing system parameters. In one embodiment, the housing has a first external dimension of about 51 mm. In another embodiment, the disk means has a diameter in the range of from about 45 mm to about 50 mm.

Abstract: Disclosed is a information storage device including a disk drive and a shock absorbent jacket for enclosing the drive. The jacket in one embodiment is comprised of a resilient material, the jacket being designed to protect the drive for shock forces imposed from any direction. In one embodiment the disk drive has a housing with a first external dimension of about 51 mm. In another embodiment, the disk drive includes a recording disk having a diameter in the range of from about 45 mm to about 50 mm. The jacket at least partially encloses each external surface of the disk drive. The jacket and the disk drive are retained within an electronic instrument.

Abstract: According to the invention, a disk drive includes a shock bumper attached to a surface of a suspension such that the shock bumper prevents contact between data region of a disk surface and the suspension that would otherwise result from displacement of the disk relative to the suspension in a direction perpendicular to the surface of the disk.

Abstract: Disclosed is a disk drive information storage device which, in one embodiment, includes a disk having a diameter in the range of about 45 to 50 min., with a housing and a spin motor. In another embodiment, the disk drive information storage device includes a disk, a housing having a first external dimension of about 51 mm., and a spin motor. The spin motor includes a rotor and a stator, with either the rotor or the stator having a plurality of winding structures associated therewith, and the other having a plurality of magnetic poles. Each winding structure is made up of two winding portions, with only one winding portion being used to drive the rotor relative to the stator upon drive currents being applied to the winding structure, but with both winding portions being used to generate back electromotive force when drive current is cut off from the winding structure. This generated electromotive force is used to actuate an actuator drive motor to unload the read/write heads from the disk surface.

Abstract: A method for individually evaluating a head and disk combination to selectively optimize and calibrate the read and write systems thereof in a short time is achieved by deliberately positioning the head off the track center-line by introducing known offset into the track position servo system. This results in reducing the data signal strength proportional to the offset while noise remains at a relatively constant level, thereby reducing the signal to noise ratio and increasing the error rate in a systematic way.

Abstract: A rotary inertial latch is disclosed for maintaining the actuator of a disk drive in its proper position when the drive is not in operation. The inertial latch includes at least one inertial body which contacts a pivotable latch member, at least when the disk drive is subject to a shock force, to move the pivotable latch member to a closed position.

Abstract: An architecture for a low profile disk drive device wherein a lower surface of an information bearing disk abutting an upper surface of a spindle motor is not accessed by a read/write head for data storage or retrieval. The disk is used as a magnetic shield to protect reading and writing from an upper surface of the disk, The architecture facilitates lower profile construction because the spindle motor can be made with a larger diameter and thinner height. Memory capacity is not sacrificed because a greater portion of the remaining disk surfaces is utilized.

Abstract: Disclosed is a disk drive information storage device which includes a disk for recording and reproducing information, the disk drive information storage device utilizing a rotary actuator, with the rotary actuator including a load beam for supporting a read/write recording element above a surface of the disk. The load beam includes at its outermost end a lift tab, with the lift tab being positioned such that a centerline of the lift tab is offset from a centerline of the load beam. The lift tab cooperates with a cam assembly to provide a dynamic head loading disk drive. The cam assembly is supported by the housing of the disk drive information storage device at a position adjacent to the edge of the disk and adjacent to the lift tab. The cam assembly in cooperation with the lift tab provides a lifting force along the centerline of the load beam.

Abstract: Disclosed is a rigid disk drive information storage device which includes a rigid disk having a diameter in the range of about 45-50 mm., with a housing having a footprint that includes a width of about 51 mm. and utilizing a rotary actuator for positioning read/write recording elements across the surface of the disk. The disk storage devices further includes a footprint with a length of about 70 mm., includes dynamic loading apparatus for loading the read/write recording elements into operative relationship with the disk and further includes an inertial latch for preventing rotation of the actuator when the drive is subjected to a rotational force.

Abstract: The run length limited encoding/decoding system of this invention includes a clock swap logic circuit, a read reference clock multiplexer circuit, a write clock skip logic circuit, an encoder start logic circuit, an encoder circuit, a read clock skip logic circuit, a decoder start logic circuit, a decoder circuit, an input data buffer and a three-state output data buffer. The encoder circuit includes a deserializer for receiving serial data from a disk controller and blocking the data into m bit words. Each m bit data word is supplied directly to an encoding combinatorial logic circuit which in turn generates an n bit code word. The n bit code word is loaded in a serializer and serially transmitted out of the serializer. The decoder circuit includes a deserializer/serializer and a decoding combinatorial logic circuit. The deserializer/serializer receives a serial stream of encoded data and converts the data into n bit code words.

Abstract: The servo field includes at least one sub-field of prerecorded information that simultaneously provides (i) data for a first servo function and (ii) data for at least one other servo function. In another embodiment, a prerecorded embedded servo field includes a first sub-field of prerecorded information that simultaneously provides (i) automatic gain control data for a third sub-field and (ii) data for a first servo function, and a second sub-field of prerecorded information that simultaneously provides (i) automatic gain control (AGC) data for the third sub-field and (ii) data for a second servo function. Since the first and the second sub-fields in the servo field of this invention are used for AGC and another servo function, the sub-fields are arranged within the servo field so that the sub-field that requires the least precise AGC control is first and the sub-field that requires the most precise AGC control is last.

Abstract: A rotary inertial latch is disclosed for maintaining the actuator of a disk drive in its proper position when the drive is not in operation.

Abstract: A silent seek servo controller is used in a low profile miniature disk drive to minimize acoustic noise and the problems associated therewith. The silent seek servo controller of this invention reduces acoustic noise generation at the expense of seek performance. Since the silent seek servo controller of this invention minimizes acoustic noise, the controller helps to eliminate vibrations within the computer. The silent seek servo controller is a one mode continuous position servo seek controller that accelerates and decelerates the actuator using a smooth, continuous and completely symmetric acceleration trajectory. Specifically, for a seek time t, the disk drive actuator is accelerated for one-half the seek time, i.e, time t/2, and decelerated for the other half of seek time t. The peak acceleration occurs at time t/4 and the peak deceleration occurs at time 3t/4. The symmetry of each acceleration phase assures that any acoustic noise generated by uneven acceleration is eliminated.

Abstract: A rigid disk drive including a rotary actuator having a lift tab extending asymmetrically from the end of the load beam which supports a slider with read/write element is disclosed. The free end of the lift tab cooperates with a cam surface on a cam assembly to provide dynamic loading and unloading of the slider while imparting a roll to the slider as it is loaded to and unloaded from the disk.

Abstract: A spin motor control system includes a BEMF commutation circuit, a startup circuit and a monitor circuit, each of which operate utilizing digital techniques. The BEMF commutation circuit includes first and second counters that are programmable to accommodate for changing system parameters. The BEMF commutation circuit does not require the incorporation of an external capacitor, is insensitive to leakage current, and provides stable timing characteristics. The startup circuit also includes a counter and is programmable to accommodate for changing system parameters. The startup circuit does not require an external capacitor and provides stable generation of the startup pulses. The monitor circuit includes first and second counters for blanking the BEMF circuitry after commutation. The monitor circuit further includes circuitry for detecting and correcting the direction of rotation of the spin motor.