An overview of the SR language and implementation

Abstract

SR is a language for programming distributed systems ranging from operating systems to application programs. On the basis of our experience with the initial version, the language has evolved considerably. In this paper we describe the current version of SR and give an overview of its implementation. The main language constructs are still resources and operations. Resources encapsulate processes and variables that they share; operations provide the primary mechanism for process interaction. One way in which SR has changed is that both resources and processes are now created dynamically. Another change is that inheritance is supported. A third change is that the mechanisms for operation invocation-call and send-and operation implementation-proc and in-have been extended and integrated. Consequently, all of local and remote procedure call, rendezvous, dynamic process creation, asynchronous message passing, multicast, and semaphores are supported. We have found this flexibility to be very useful for distributed programming. Moreover, by basing SR on a small number of well-integrated concepts, the language has proved easy to learn and use, and it has a reasonably efficient implementation.

Anonymous remote computing: a paradigm for parallel programming on interconnected workstations

“…Networking of multiple multiprogrammed machines led to a direct adaptation of this model to distributed programming as in SR [5] and Lynx [35], and subsequently to parallel programming as in PVM [40]. The trends in the cluster computers show proliferation of a large number of heterogeneous workstations in a LAN configuration.…”

μC++: Concurrency in the object‐oriented language C++

“…This avoids complex selection expressions and possibly their repeated evaluation. In addition, this allows all the programming language constructs and data structures to be used in making the decision to postpone a request, instead of some fixed selection mechanism provided in the programming language, as in SR [19] and Concurrent C++ [20].…”

“…Unfortunately, this scheme causes code at the beginning of a deferred member to be executed multiple times, which can result in complex switching logic at the start of entry routines to determine whether or not execution has resulted from a REENTER, and if so, why it was deferred. SR SR [19] provides concurrent objects that can have both concurrent member routines and entry members with Ada style accept statements. The way in which a member is invoked (by a call or send) indicates whether or not the caller blocks until the called member is finished.…”

An Inter-entry Invocation Selection Mechanism for Concurrent Programming Languages

“…Ada [12], Concurrent C [9], CSP [11,15,10], Erlang [3], Hermes [17], JR [14], Limbo [8], occam [5,16], Orca [4], SR [2,1], and SRR [7] each provide support for multi-way receives, but with differing expressive power. None of these languages provides general support for inter-entry invocation selection.…”