Terminology

The SCA specifications 1 collectively define many terms that are used throughout the Tuscany SCA implementation, for example, SCADomain, Composite, Component, Service, Reference. Tuscany itself uses a few terms that are worth explaining.

Distributed Domain

An SCA Domain (complete runtime configuration) that is "distributed over a series of interconnected runtime nodes".

Runtime

A runtime groups together one or more (distributed) nodes. It describes the compute resources that will run the components of an SCA Domain.

Node

Provides an environment inside which SCA component instances execute. It's an operating system process, separate from other Nodes. Its form may be as simple as a single Java VM or it may take the more scalable and reliable form, such as a compute cluster.

References

1 http://www.osoa.org/display/Main/Service+Component+Architecture+Specifications