Oz is a concurrent language where users can create dynamically any number of sequential threads that can interact with each other. However, in contrast to conventional concurrent languages, each Oz thread is a dataflow thread. Executing a statement in Oz proceeds only when all real dataflow dependencies on the variables involved are resolved. The Mozart system supports network-transparent distribution of Oz computations. Multiple Oz sites can connect together and automatically behave like a single Oz computation, sharing variables, objects, classes, and procedures.
Sites disconnect automatically when references between entities on different sites cease to exist.
In a distributed environment Oz provides language security. That is, all language entities are created and passed explicitly. An application cannot forge references nor access references that have not been explicitly given to it. The underlying representation of the language entities is inaccessible to the programmer. This is a consequence of having an abstract store and lexical scoping.