Communications among distributed Ada programs

The authors describe a capability for Ada programs to send messages to other Ada programs in a distributed, heterogeneous processing environment. This capability is intended primarily to support real-time applications. Copying of data and the use of protocol layers are kept to a minimum. The system supports dynamic reconfiguration and sophisticated fault management schemes. The network topology consists of a collection of nodes connected by arbitrary communication links. More than one link can emanate from a node, and the links can represent completely dissimilar communications capabilities. Any two nodes in the system can be connected, either directly or indirectly, by more than one link. The communication model is that of a persistent connection maintained between programs. Programs send and receive messages through ports. Distributed communication is modelled after the file I/O in the Ada language