Abstract: A location update protocol is provided for use in a mobile communications network having a distributed cache for managing subscriber profile information associated with each of a plurality of subscribers of the network. The network includes a plurality of base stations each including a memory unit having a local database for storing: a local subscriber list including a plurality of locally owned cache entries each having an associated subscriber key value, and an associated locally owned subscriber profile; and a global subscriber list including a plurality of global cache entries each having an associated subscriber key value, and an associated location value indicating a node in the network at which an associated subscriber profile is stored. Each of the base stations is operative to transfer and copy selected ones of the cache entries to other ones of the base stations for the purposes of managing and accessing the distributed cache.

Abstract: An improved carousel apparatus for use in carousel-type magnetic tape library systems and the like, including a cylindrical magazine carried by a rotatable turntable. The turntable includes a sprocket wheel that is engaged by a drive belt or chain connected to a stepper motor affixed to a rotatable base plate. Affixed to the sprocket is a shutter plate having a plurality of notches in its perimeter for detection by an optical-indexing sensor. The apparatus also includes a carousel-indexing sensor and a cartridge-in-carousel and cartridge-orientation sensor. Disposed within the central cavity of the carousel magazine unoccupied by cartridges is a cartridge-onloading/offloading mechanism which is rotatably mounted concentric with the carousel turntable.