Abstract: A method and apparatus are disclosed for providing continuous position information in a position servo system having position information signals 162, 164 coming from encoder 160 and which provide indirect position information over selected ranges, and a reference position information signal 153 coming from transducer 140 and which provides reference position information at discrete intervals. In the preferred embodiment, the distances between selected positions of two position information signals are combined, and in response to position offset information obtained from the reference position signal 153, thereafter used in selecting which of the position information signals 162, 164 will be used for determining position information. The position determination techniques are further employed in positioning the transducer apparatus 140 relative to a rotating storage medium 142 through the use of an externally commutated positioning apparatus, such as motor 100, under control of a processing element 30.

Abstract: A method and apparatus are disclosed for positioning a transducing apparatus relative to a rotating storage medium through the use of an externally commutated positioning apparatus under control of a processing element. In addition, a control method is disclosed which includes an initial determination of salient parameters associated with the apparatus. Positioning of the transducing apparatus is achieved through a plurality of control modes which are responsive to the determined parameters. In addition, the accuracy with which position of the transducing apparatus is determined varies among the modes with the remaining distance yet to traverse to a desired destination position.