Abstract: Embodiments of the invention provide a magnetic disk unit in which there has been adopted a structure fixing a base and a top plate and preventing a deformation by a bimetal effect. In one embodiment, the magnetic disk unit includes a magnetic disk; a head drive mechanism in which is mounted a head accessing the magnetic disk; a base accommodating the magnetic disk and the head drive mechanism, and possessing a flat part, in which a threaded hole has been formed, in a circumference of an opening edge; and a top cover which is formed by a material whose thermal expansion coefficient differs from that of the base, in which there is provided an escape hole, for a screw, position-aligned to the threaded hole of the flat part, and which is attached to the base by the screw penetrating through the threaded hole and the escape hole for the screw.

Abstract: Embodiments of the invention provide a magnetic disk unit in which there has been adopted a structure fixing a base and a top plate and preventing a deformation by a bimetal effect. In one embodiment, the magnetic disk unit includes a magnetic disk; a head drive mechanism in which is mounted a head accessing the magnetic disk; a base accommodating the magnetic disk and the head drive mechanism, and possessing a flat part, in which a threaded hole has been formed, in a circumference of an opening edge; and a top cover which is formed by a material whose thermal expansion coefficient differs from that of the base, in which there is provided an escape hole, for a screw, position-aligned to the threaded hole of the flat part, and which is attached to the base by the screw penetrating through the threaded hole and the escape hole for the screw.

Abstract: Gain information in a read amplifier, which is recorded when data to be measured is reproduced, is stored in an AGC control memory circuit in advance. By reproducing the data using the gain information, reproduced data varied according to the amount of flotation of a magnetic head and the position of the magnetic head alone can be obtained. A variation in voltage amplitude of the reproduced data is detected by an envelope signal generating circuit and a variation in phase difference between a reading cycle in which the reproduced data is read and a reference cycle is detected by a phase difference signal generating circuit. A calculator calculates a float interval of the magnetic head and a variation in the position thereof based on these detected variations. As a result, a decision can be made as to whether the float interval of the magnetic head and the variation in the position thereof exceed an allowable range.

Abstract: A structure for supporting a magnetic head slider for a linear magnetic disk unit comprises: a magnetic head slider having air bearing rails located opposite to a magnetic disk so as to extend in a direction of a track of the magnetic disk; a gimbal for elastically supporting the magnetic head slider, the gimbal being bonded to a back surface of the magnetic head slider on a side reverse to the air bearing rail; and a support arm having the gimbal secured to its distal end, whose axis extends in a direction perpendicular to the air bearing rail, which support arm gives the magnetic head slider a pressing force toward the magnetic disk.