This standard describes the syntax and semantics of the protocol messages that pass between the Drive Manager (DM) and the Media Manager (MM). The Library Manager (LM) exists only in the context of a larger Media Management System (MMS); a thorough understanding of the architecture of the MMS as described in IEEE Std 1244.1-2000 is a prerequisite. In addition@ certain elements common to all of the modules in the MMS are described in P1244.2/D041900. 1 The MM itself@ a system that operates as a peer process with the LM@ is described in IEEE Std 1244.3-2000.