Stephen Crane

A configurable protocol architecture for CORBA environments

Describes a flexible architecture for building the protocols required to allow interaction between distributed objects in a CORBA environment. A key feature of the architecture is its ability to select the elements of a protocol stack dynamically at bind-time depending on the properties of the interface being accessed. This permits multiple object-invocation protocols to coexist such that a system may support local, intra-ORB (object request broker) and inter-ORB protocols and allows the selection of the most appropriate protocol at run-time. In addition, the architecture is capable of supporting non-standard interaction protocols such as multimedia streams. This paper outlines the architectural principles used and describes an efficient implementation of the CORBA Internet Inter-ORB Protocol.

Constructing distributed Unix utilities in Regis

REGIS is an environment for constructing distributed programs and systems. A characteristic of REGIS programs is separation of structure from algorithm, often referred to as the software integrated circuit approach to program construction. Programs consist of components connected by links. Components are of two types: they may be primitive, or composed from other components. Primitive components in REGIS are single-threaded C++ objects and their compositions are described in the structural language DARWIN. A variety of communication objects and paradigms is supported. The authors provide a brief introduction to writing REGIS programs followed by a detailed description of the design of a real program called red, with particular emphasis on the advantages of the REGIS approach.<<ETX>>

A uniform approach to configuration and communication in distributed systems

This paper describes the design and implementation of extensions to the Regis distributed programming platform which add protocol stacks to communication endpoints. Although the initial goal was to extend Regis to support multiple transport protocols, groupcast and multimedia communication, the dynamic nature of the protocol framework allowed new approaches to the design of communication protocol software. Transient protocol layers provide support for binding establishment and connection management in a manner which is largely transparent to the user of the endpoint. The paper describes this approach through examples and shows how it leads to greater efficiency and a greater degree of code reuse.

Constructing multi-user applications in REX

Presents a configuration language based approach to the description and construction of distributed multiuser applications. The authors describe the facilities of the configuration language DARWIN which permit the description of multiuser applications in a manner identical to normal configuration-based parallel or distributed programs. The implementation platform, REX, is described, as is Conf, a distributed conferencing programs which, while simple, illustrates several of DARWINs important and powerful features.<<ETX>>

Multiprocessors and multiprocessing in a distributed system

A distributed object-oriented architecture called DUMPS with explicit primitives for exploiting parallelism that are hardware-independent is proposed. Multiprocessors do not appear as separate entities in the model, but are treated in the same way as multiple uniprocessor nodes. Synchronization and communication between processes is in terms of objective-invocations, so the model does not rely on the availability of shared memory. Continuity of the face of failure a vital characteristic of the system, is discussed.<<ETX>>