Abstract: An alternating "A/B" servo burst pattern for measuring and compensating for offset of the track centerline due to differential magnetic influence to the servo pattern, and a switching network to alternate the output of the servo system demodulators between the inverting and non-inverting terminals of a differential amplifier so that electrical distortion is minimized.

Abstract: An alternating "A/B" servo burst pattern for measuring and compensating for offset of the track centerline due to differential magnetic influence to the servo pattern, and a switching network to alternate the output of the servo system demodulators between the inverting and non-inverting terminals of a differential amplifier so that electrical distortion is minimized.

Abstract: A case sealed by a strip of pressure-sensitive tape having an integral end portion of the tape at an end thereof folded back on the adhesive face of the tape and adhered thereto to form a tab which is unadhered to the case for being grasped and pulled to peel the tape away from the case, and a method of and apparatus for taping cases with this easy-open feature.

Abstract: A technique is provided for detecting defects in data apparatus, such as magnetic storage apparatus, wherein recovered data pulses are expected during periodic window intervals. Data pulses which may be phase shifted relative to predetermined data pulse times of occurrence are recovered, such as by playing back such pulses from a magnetic storage medium, for example, a hard disk drive. The recovered data pulses are selectively delayed, and the delayed and undelayed data pulses are multiplexed into a stream. The occurrences of such data pulses in the stream within the aforementioned window intervals are detected to provide indications of defects. A defect is indicated if a pulse in the stream does not occur within the window interval.

Abstract: A case sealed by a strip of pressure-sensitive tape having an integral end portion of the tape at an end thereof folded back on the adhesive face of the tape and adhered thereto to form a tab which is unadhered to the case for being grasped and pulled to peel the tape away from the case, and a method of and apparatus for taping cases with this easy-open feature.

Abstract: An improved automatic gain control circuit suitable for use in the servo loop controlling the position of magnetic read/write heads with respect to magnetic disk data storage media is disclosed. The AGC circuit features a fast loop and a slow loop each of which loops contain gain varying elements, which in the preferred embodiment comprise field effect transistors. By using a reference voltage to control the operating point of the variable gain element in the fast loop, the effects of mechanical resonances on the servo data can be substantially eliminated while the overall AGC system response exhibits a substantially constant bandwidth.