The present invention is directed to an optical switch for switching the light from one of a plurality of inputs to one of a plurality of outputs. The assistance method comprises a step of selecting at least one strip out of the plurality of strips of the track, said strip being selected according to its level of wear. An integrated circuit is mounted on the upper surface. The diffracting elements may be adjusted according to electrical signals of a program from a computer. A digital signal processor interface to the drive electronics of the CD drive, a dynamic random access memory controller, an error correction code data corrector, an error detection and correction device employing cyclical redundancy checking techniques, and a host computer interface are described. When a second server is dependent on a first server during the installation process, the first server may finish a task and send a message to the second server to attempt an installation step that depends on the first server.