Message-passing

Distributed objects

Message-passing systems use either distributed or local objects. With distributed objects the sender and receiver may be on different computers, running different operating systems, using different programming languages, etc. In this case the bus layer takes care of details about converting data from one system to another, sending and receiving data across the network, etc. The Remote Procedure Call (RPC) protocol in Unix was an early example of this. With this type of message passing it is not a requirement that sender nor receiver use object-oriented programming. Procedural language systems can be wrapped and treated as large grained objects capable of sending and receiving messages.