Abstract: A head crash in a hard disc drive is predicted by periodically measuring a head-disc contact energy level on an actuator arm supporting the head and identifying a predetermined change in the energy level between at least two energy level measurements. The head-disc contact energy level is measured by a positioning microactuator on the actuator arm, and comparing that energy level to a threshold established during an earlier or selected contact start-stop cycle. A circuit is coupled to the microactuator and is periodically operable to identify a magnitude of contact energy. An indicator is coupled to the circuit and responsive to the representations to indicate presence of symptoms of an impending crash.

Abstract: A dual plane single-stage actuator is disclosed. The actuator includes a step portion between the coil and head support portions, which increases its stiffness while permitting the coil support portion and head support portion of the actuator to lie in different planes. This allows the actuator to be installed in low-profile drives.

Abstract: The present invention provides a method to determine and to locate the position of the imbalance torque of an actuator in a disc drive. There are several steps performing different functions in the method. The first step of the method performs the function of obtaining a difference in the voice coil motor (VCM) current of the disc drive in the X orientation and in the Y orientation with the VCM current of the disc drive when the disc drive is placed flat. The second step performs the function of obtaining the square of each difference in VCM current. The third step performs the function of obtaining the imbalance by adding the square of the VCM current and subsequent square root of the addition. The valve of the imbalance torque is obtained by multiplying the imbalance with the torque constant. The fourth step performs the function of obtaining a division value of the VCM current in the X orientation or in the Y orientation with the VCM current of the disc drive when the disc drive is placed flat.

Abstract: A preferred system for measuring bearing friction first measures voice coil motor current values required to move an actuator arm assembly to each of several cylinder position intervals. Torque values required to move the actuator arm assembly are then computed using the measured voice coil motor currents. Drive-level bearing friction values are then calculated using the computed torque values and then combined into a composite indicator.

Abstract: A disc drive with improved servo-mechanical frequency response includes a rotary actuator assembly incorporating stiffening members disposed along the sides of its actuator arms. In one embodiment the stiffening members comprises edge rails. The edge rails may rise from only the upper surface of the actuator arm or from both the upper and lower surfaces. In one embodiment the stiffening members comprise wings which project upward from the sides of the actuator arm.

Abstract: A dual plane single-stage actuator is disclosed. The actuator includes a step portion between the coil and head support portions, which increases its stiffness while permitting the coil support portion and head support portion of the actuator to lie in different planes. This allows the actuator to be installed in low-profile drives.

Abstract: A head crash in a hard disc drive is predicted by periodically measuring a head-disc contact energy level on an actuator arm supporting the head and identifying a predetermined change in the energy level between at least two energy level measurements. The head-disc contact energy level is measured by a positioning microactuator on the actuator arm, and comparing that energy level to a threshold established during an earlier or selected contact start-stop cycle. A circuit is coupled to the microactuator and is periodically operable to identify a magnitude of contact energy. An indicator is coupled to the circuit and responsive to the representations to indicate presence of symptoms of an impending crash.

Abstract: The present invention provides a method to determine and to locate the position of the imbalance torque of an actuator in a disc drive. There are several steps performing different functions in the method. The first step of the method performs the function of obtaining a difference in the voice coil motor (VCM) current of the disc drive in the X orientation and in the Y orientation with the VCM current of the disc drive when the disc drive is placed flat. The second step performs the function of obtaining the square of each difference in VCM current. The third step performs the function of obtaining the imbalance by adding the square of the VCM current and subsequent square root of the addition. The valve of the imbalance torque is obtained by multiplying the imbalance with the torque constant. The fourth step performs the function of obtaining a division value of the VCM current in the X orientation or in the Y orientation with the VCM current of the disc drive when the disc drive is placed flat.

Abstract: A preferred system for measuring bearing friction first measures voice coil motor current values required to move an actuator arm assembly to each of several cylinder position intervals. Torque values required to move the actuator arm assembly are then computed using the measured voice coil motor currents. Drive-level bearing friction values are then calculated using the computed torque values and then combined into a composite indicator.