A rotation hinge configured in a portable electrical device includes a tube sequentially stringing a base coupled to a main housing of the portable electrical device, a cam module and a fixing plate coupled to a sub-housing of the portable electrical device, and engaging with a riveting plate. The cooler wall includes inner and outer collapsible walls that extend from the upper rim and a common bottom wall. The first electrical connection is created between the read sensor and the first and second shields, and is severed when the wafer is cut and lapped along the ABS. The semiconductor laser element and the light receiving element are mounted on the lead frame. The main pole and the return pole constitute a magnetic path of the magnetic field. The method includes verifying, in response to a write command to store data in the logical volume, that a physical storage location is available in the physical storage and, if the physical storage location is available, then storing the data at the physical storage location.