Abstract: A magnetic disk drive of the type in which a disk assembly has a dedicated servo surface containing circular tracks of dedicated servo signals and data surfaces containing circular data tracks divided into sectors each of which includes a data field and a servo field containing embedded servo signals, a dedicated servo signal detector for detecting servo signals on said dedicated surface, an embedded signal detector for detecting embedded servo signals on a data surface and a head positioning system for positioning a read/write head over a selected data track. The entire output of the embedded signal detector is combined with the high-frequency components of the output of the dedicated signal detector to produce a composite track error signal and the head positioning system responds to the composite track error signal to maintain the read/write head over the selected data track.

Abstract: A misposition correction system for correcting misposition errors due to spindle runout and other slowly varying errors in a servo positioning system of a magnetic disk storage device. The system includes means for dynamically measuring misposition error with respect to a data track centerline using an anti-aliasing analog filter, means for digitizing the measured analog signal and for removing selected harmonics of the fundamental-frequency of the resulting cyclic error signal, means for transforming the digitized error signal by a matched digital filter whose transfer function contains independently adjustable DC gain, fundamental-frequency gain, and phase lead components thereby to generate a misposition error correction signal that matches the electrical and mechanical response characteristics of the servo system.