Embedded middleware: State of the art

Java, WWW, Internet and CORBA technologies will be enabling software technologies which make it possible to develop independent applications capable of communicating over various kinds of networks. Thus, embedded programs form networked client/server applications. Within these applications, they perform tasks, functioning as a part of a larger entity in a distributed network. Currently, firms have their own specialized solutions which require considerable maintenance resources. During development phase, the interoperability and extendibility of the systems are not given enough attention. Because of this, the solutions become rapidly obsolete. For several enterprises, a standardised solution for communications is in demand. Middleware is a general term that has come to represent a variety of distributed computing services in application development environments. Middleware products operate between the application logic and the underlying physical network. Embedded middleware provides standard communication services and object-oriented integration interfaces for networked embedded applications. The maturity of the commercial middleware products based on CORBA is insufficient and some of the services required in embedded systems are still unavailable. DCOM-based OPC will be a suitable solution for base stations that control data acquisition, monitoring and presentation. However, before it can be considered a suitable solution for client application executed in laptops or handheld PCs, OPC requires commercially available driver software. Embedded middleware requires communication services for remote procedure calls, events and messaging. If the system is connected to the Internet or other open networks, naming and security services are required as well. These services, and the generic interfaces which isolate the middleware from the operating system and protocols, have to be provided as component-based software which enables restricted adaptability during product life cycle. In future, applications will be composed of different types of components such as Java beans or applets, ActiveX components or CORBA components. Each of these component types requires its own interface technology.