. . " the magnetic head supporting mechanism shown in FIG. 19, wherein FIG. 20A shows an unloaded state and FIG. 20B shows a loaded state;FIGS. 21A to 21D are diagrams showing a fourth variant of the present invention, wherein FIG. 21A is a plan view, FIG. 21B shows a side view, FIG. 21C is a plan view showing a region a major part of which is occupied by a slider, and FIG. 21D isa cross-sectional view" . .