Abstract: According to one embodiment, a magnetic disk device writes a plurality of simulated reference patterns to the magnetic disk on write conditions different from each other, detects a write state of each of the simulated reference patterns, selects one of the write conditions according to detection results, and writes a plurality of regular reference patterns which become criteria for predetermined processing to be executed on the magnetic disk to the magnetic disk on the selected write condition.

Abstract: This massager utilizes percussion waves produced by a powerful hand-held or stationary drive, such as an electric hammer, magnetic hammer or pneumatic hammer, for massaging human bodies. The massager includes an intermediate idler connected to an oscillator rod operated by a drive unit and a hitting pad connected to the intermediate idler. A lower end of the oscillator rod slides freely inside an upper axial cavity in the upper part of the intermediate idler. A lower part of the intermediate idler is linked to a hitting pad through a control spring. This control spring creates a gap for vibration between the lower end of the intermediate idler and the hitting pad.