Systems and techniques for transmitting data stream to a client include transmitting a data segment from one of a plurality of nodes of a continuous media server to a client according to a scheduler on the node. At least one cartridge is mounted adjacent the face surface and selectively slidable along the directional feature to provide adjustment. At this point, no limitation is put on the current flowing through the radial position controlling electromagnet, etc. The controller may send further queries to the access node to be executed in further identifying the device.