A reference voltage source circuit, which can generate a sufficiently low reference voltage and which can stably operate at temperatures above 80 degrees Celsius, is provided. The centrifuging compartment includes a housing defining a inlet on a top thereof and a sealing cover pivotably coupling to the housing to cover the inlet. The heat radiation member is provided on at least one of the two side faces of the cabinet for each disk module, which are parallel to the recording surface of the disk. Each recess has a depth which increases in a direction of relative angular displacement between the two crown parts, considered from the peripheral surface, over a length which corresponds to the length of the plate, to a value which is substantially equal to the thickness of the plate. The housing and the internal component are adapted to provide for the assembly of the first component of the prosthesis to the second component of the prosthesis. The cyclic replacement counter addresses each cell in the cache to determine if the cell is still in use or may store a new answer.