An apparatus and method for improving cache performance in a computer system having a multi-level cache hierarchy. The furnace section includes a reduction tank, a material inlet door, a magnesium crystal collecting machine, and a residue exhaust pipe. Subsequent advancement of the compression sleeve within the axial conduit, with the assistance of a compression tool, forces the deformable leading end of the compression sleeve radially inward to compress the cable jacket and braid thereby providing secure attachment of the connector to the cable. A line switch configured to selectively switch an optical transmission line to be connected with the terminal unit, from the second optical transmission line to another optical transmission line based on the first failure detected by the detecting section and the second failure detected by the second monitoring section.