Abstract: A method of controlling track seeking and track following of a head in a disk file having servo information recorded thereon to provide a track number and a position error signal (PES). The physical parameters of the disk file are modeled by at least three sets of constants associated with selected numbers of tracks. An actuator is connected to the head by a support arm assembly and is responsive to a control signal for positioning the head. The method comprises, for each servo information sample, the steps of predicting a relative position, velocity, and bias of a data head. It is determined whether the predicted relative data head position corresponds to the selected number of tracks, if not, at least the predicted relative data head position is rescaled to form the predicted relative data head position to correspond to the selected number of tracks of the predicted data head position prior to rescaling.

Abstract: Apparatus for testing the integrity of a plurality of conductive circuit connection paths between output pins on a first integrated circuit and input pins on a second integrated circuit on a circuit board includes first boundary scan cells associated with each output pin on the first integrated circuit, each of the first boundary scan cells adapted to selectively place a data test bit loaded therein onto the one of the output pins with which it is associated, second boundary scan cells associated with each input pin on the second one of the integrated circuits, each of the second boundary scan cells adapted to selectively store the digital value present on the one of the input pins with which it is associated, a controller for loading a data test bit into each of the boundary scan cells associated with each output pin on the first one of the integrated circuits, for respectively placing each of the data test bits onto respective ones of the output pins of the first integrated circuit, for selectively storing

Abstract: A static bi-stable mechanical latch comprises a latch member pivotally mounted to a frame and rotatable between an opened-position stop and a closed-position stop. The latch member includes a first arm having a hooked end and a magnetic mass mounted thereon, and a second arm having a latch coil and a soft magnetic mass mounted thereon. The second arm is also provided with a tang or bump. The actuator is provided with an angular protuberance and a tip which is captured by the hooked end of the latch member when the actuator arm is positioned so that the head is in the landing zone and the latch member is in the closed position. The pivot point of the latch member is positioned so the angular protuberance of the actuator arm engages the tang or bump when the actuator is moving towards the landing zone and is in a preselected position close to or in the landing zone.

Abstract: Apparatus for preventing data corruption on a disk due to mechanical shock occurring during the write process to the disk includes a mechanical shock sensor to sense mechanical shocks having a magnitude exceeding a predetermined threshold. Write disable circuitry responsive to the mechanical shock sensor interrupts the write current to the disk drive write head. Repositioning circuitry then repositions the data head over the original data track and the incomplete data that was interrupted by the mechanical shock is rewritten.