Middleware is connectivity software that consists of a set of enabling services that allow multiple processes running on one or more machines to interact across a network. Middleware is essential to migrating mainframe applications to client-server applications and to providing for communication across heterogeneous platforms. This technology has evolved during the 1990s to provide for interoperability in support of the move to client-server architectures. The most widely-publicized middleware initiatives are the Open Software Foundation's Distributed Computing Environment (DCE), Object Management Group's Common Object Request Broker Architecture (CORBA), and Microsoft's COM/DCOM (COM, DCOM).