The main language constructs are resources and operations. SR provides a novel integration of the mechanisms for invoking and servicing operations. Consequently, all of local and remote procedure call, rendezvous, message passing, dynamic process creation, multicast, and semaphores are supported.
SR also supports shared global variables and operations.
SR has been used at a number of universities and labs for course work and research projects involving concurrent programming. It has been used in concurrent programming courses to reinforce concepts with small programming projects and with larger projects such as experiments with parallel algorithms, replicated databases, distributed simulations, and parts of distributed operating systems such as file systems and command interpreters. SR has also been used as a tool in several masters theses and doctoral dissertations to conduct experiments in parallel and distributed programming and to implement larger systems such as a system for mixed language programming, one for distributed implementation of graph algorithms, experiments with load balancing algorithms, and experiments with upcall program structures. SR is the predecessor to the MPD programming language, which provides the same capabilities using the syntax described in Foundations of Multithreaded, Parallel, and Distributed Programming .