Antonelli, Terry, Stout & Kraus
Alignment disk for magnetic disk driving apparatus and method and apparatus for verifying tracking error of the magnetic disk driving apparatus
 An alignment disk having an adjust signal recorded thereon to maintain data interchangeability of a magnetic disk drive apparatus and loadable and unloadable to and from the magnetic disk drive apparatus, and method and apparatus for verifying a tracking errors of the magnetic disk drive apparatus are disclosed; the magnetic disk drive apparatus including magnetic head means for recording and reproducing data on and from a magnetic recording medium, a head carriage for carrying the magnetic head means, and drive means for driving the head carriage radially of a track of the magnetic recording medium; the alignment disk having a set of track diameter adjust signal pairs recorded on tracks equal to or larger in number than the number of phases of a stepping motor for driving the head carriage and corresponding to at least the excitation phases of the stepping motor; the set of track diameter adjust signal pairs each having an inner track signal and an outer track signal extending inward and outward from a center of the track; and the set of track diameter adjust signal pairs being arranged symmetrically about a rotation axis of the disk. 
Hitachi, Ltd.
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Kazuo Yasumasa Takeo Yousuke Shinji Seiichi Junichi Masayoshi Hiroshi Tetsuro Toshiaki Hitoshi Kazuei
Kikuchi Saito Sonobe Nagano Mizunuma Hayashi Enomoto Sunada Kanai Hatakeyama Suematsu Ishida Saito