There is provided a magnetic disk drive in which a flying-height fluctuation produced by the operation of a fine actuator is decreased, the reliability is high, and recording density is high. 3 mils thick, is placed over trellised grapevines and fastened by the disclosed tie downs at the respective canopy sides. In another embodiment, a special investor is arranged. The data source connection interface stores an available BIOS program code matching with the BIOS.