A reusable plastic fastener has an elongated shank having two flexible curved flanges secured thereto and a head secured to a central portion of the shank. The protection means may comprise an earth conductor and insulating means configured to form an insulating barrier between the conductive parts of the rigid cable. In a logical partitioning machine, the open firmware partition manager can utilize the data structure to support the partition’s open firmware device tree construction. Also described are methods of using the compositions.