A programmable resistance memory employs a feedback control circuit to regulate the programming current supplied to a selected programmable resistance memory element. A node obtains multiple routes for a destination, prioritizes the routes, and installs multiple routes in the routing table, including at least the preferred route and the alternate route. In response to a read request for a particular block the method attempts to read the block from the data volume. Also, a method allocates addresses in the bus system. The adjusting device is mounted below the sole and includes a screw rod and a screw rod jacket. Techniques are disclosed to perform the method in both an over-balanced and under-balanced environment.