The present invention uses the storage resources of a storage system effectively, thereby reducing the cost of the storage system and improving its usability. Axial displacement is used to force the fingers radially outward. The first selection component is configured to receive a first mode signal and generate a first selection signal based on at least information associated with the first mode signal. The system also includes a modular supply-return connector that can be connected to the branch outlet and branch inlet of the transition adaptor and to other supply-return connectors. At least a portion of a signal received from the distance measuring device is reflected back to the distance measuring device by a receiving reflector. As the non-volatile memory degrades, the caching policy can be varied such that the non-volatile memory is used more as a read cache and less as a write cache.