Magnetic disk drive, magnetic disk drive manufacturing method and method of estimating gas amount in magnetic disk drive

摘要

Embodiments of the present invention provide a magnetic disk drive that can estimate the amount of gas filled in a housing precisely and simply. According to one embodiment, a magnetic disk drive including a housing in which a magnetic disk and a magnetic head are accommodated and gas having lower density than air is filled, a heating body provided in the housing, and means for holding a reference value of a parameter representing the temperature change speed of the heating body when the heating body is heated in the housing filled with a predetermined reference amount of the gas.