Distributed Object Computing Models
There are three main, code-centric distributed computing infrastructures: CORBA, RMI, and COM+.
CORBA, the Common Object Request Broker Architecture, is a language-neutral distributed infrastructure that allows programs written in C, C++, Java, and even Cobol to communicate across networks.
RMI, a Java-based technology, allows Java programs to exchange data and trigger remote method calls across Java networks.
COM+, a Microsoft-centric technology, allows Windows platforms to communicate.
Although CORBA, RMI, and COM+ are well-established technologies that support distributed communication across networks, they all suffer one major drawback: lack of interoperability. Because CORBA, RMI, and COM+ sit atop different transport technologies, direct communication between them is impossible. CORBA runs ovcr IIOP, RMI runs over RMI/IIOP, and COM+ runs over DCOM. CORBA can't easily communicate with RMI, COM+ can't easily communicate with RMIno one of these technologies can talk to another without the added complexity of some bridging technology. As a result, users are forced to live in the network universe defined by their object infrastructure selection.