In the last 30 days

• Open/close An introduction to snapshot algorithms in distributed computing

  A D Kshemkalyani et al 1995 Distrib. Syst. Engng. 2 224 Tag this article

  Article References Full text PDF (807 KB)

  Recording on-the-fly global states of distributed executions is an important paradigm when one is interested in analysing, testing, or verifying properties associated with these executions. Since Chandy and Lamport`s (1985) seminal paper on this topic, this problem is called the snapshot problem. Unfortunately, the lack of both a globally shared memory and a global clock in a distributed system, added to the fact that transfer delays in these systems are finite but unpredictable, makes this problem non-trivial. This paper first discusses issues which have to be addressed to compute distributed snapshots in a consistent way. Then several algorithms which determine on-the-fly such snapshots are presented for several types of networks (according to the properties of their communication channels, namely, FIFO, non-FIFO, and causal delivery).

• Open/close GEM: a generalized event monitoring language for distributed systems

  Masoud Mansouri-Samani and Morris Sloman 1997 Distrib. Syst. Engng. 4 96 Tag this article

  Article References Full text PDF (303 KB)

  Event-based monitoring is critical for managing and debugging networks and distributed systems. This paper presents GEM - an interpreted generalized event monitoring language. It allows high-level, abstract events to be specified in terms of combinations of lower-level events from different nodes in a loosely coupled distributed system. Event monitoring components can thus be distributed within the system to perform filtering, correlation and notification of events close to where they occur and thus reduce network traffic. GEM is a declarative rule-based language in which the notion of real time has been closely integrated and various temporal constraints can be specified for event composition. The paper discusses the effect of communication delays on composite event detection and presents a tree-based solution for dealing with out-of-order event arrivals at event monitors.

• Open/close A software architectural design method for large-scale distributed information systems

  Hassan Gomaa et al 1996 Distrib. Syst. Engng. 3 162 Tag this article

  Article References Full text PDF (347 KB)

  This paper describes a software architectural design method for large-scale distributed information systems. The method, which is part of an integrated design and performance evaluation method, addresses the design of client/server software architectures, where the servers need to cooperate with each other to service client requests. The goal of this software architecture is to provide a concurrent message based design that is highly configurable. The method is illustrated by applying it to the design of a complex software system, the Earth Observing System Data and Information System (EOSDIS) Core System.

• Open/close A comparison of DQDB and FDDI for the interconnection of LANs

  R Ahmad and F Halsall 1994 Distrib. Syst. Engng. 1 127 Tag this article

  Article References Full text PDF (454 KB)

  The paper identifies the design issues that must be considered when interconnecting IEEE 802 LANs through either DQDB or FDDI backbone subnetworks using MAC bridges. A series of simulation results are presented that compare the performance of both subnetwork types for various types of LAN traffic, backbone subnetwork sizes (physical coverage and number of LANs) and other performance-critical parameters. The paper concludes with some guidelines to be followed to achieve an optimal performance to meet specific application requirements.

• Open/close Mobile Objects and Agents (MOA)

  Dejan S Milojicic et al 1998 Distrib. Syst. Engng. 5 214 Tag this article

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  This paper describes the design and implementation of the Mobile Objects and Agents (MOA) project at the Open Group Research Institute. MOA was designed to support migration, communication and control of agents. It was implemented on top of the Java Virtual Machine, without any modifications to it. The initial project goals were to support communication across agent migration, as a means for collaborative work; and to provide extensive resource control, as a basic support for countering denial of service attacks. In the course of the project we added two further goals: compliance with the Java Beans component model, which provides for additional configurability and customization of agent system and agent applications; and interoperability, which allows cooperation with other agent systems.

  This paper analyses the architecture of MOA, in particular the support for mobility, naming and locating, communication, and resource management. Object and component models of MOA are discussed and some implementation details described. We summarize the lessons learned while developing and implementing MOA and compare it with related work.

• Open/close DIVE: a scaleable network architecture for distributed virtual environments

  Emmanuel Frécon and Mårten Stenius 1998 Distrib. Syst. Engng. 5 91 Tag this article

  Article References Full text PDF (114 KB)

  We introduce the network software architecture of the distributed interactive virtual environment platform. The platform is designed to scale with a large number of simultaneous participants, while ensuring maximum interaction at each site. Scalability is achieved by making extensive use of multicast techniques and by partitioning the virtual space into smaller regions. We also present an application-level backbone that can connect islands of multicast-aware networks together.

• Open/close Meeting the real-time synchronization requirements of multimedia in open distributed processing

  G Coulson and G S Blair 1994 Distrib. Syst. Engng. 1 135 Tag this article

  Article References Full text PDF (943 KB)

  Distributed systems has been an area of intense activity over the past ten years. The subject is entering a stage of maturity with work now focusing on standards for open distributed processing (ODP). Recently, however, a number of new challenges have emerged for distributed systems. Among these challenges, distributed systems are increasingly having to support multimedia services, and this has raised a number of issues for distributed systems designers. One of the most important issues in this area is that of synchronization. Multimedia applications require sophisticated support for synchronization both to coordinate multimedia presentations and to maintain timing relationships between a number of real-time data transmissions. Current distributed system architectures do not support such services. The paper discusses the problem of incorporating support for synchronization in open distributed system architectures. It is argued that support must be provided for synchronization both in the invocation mechanism and in the form of new services called streams and synchronization managers. The proposals are compared to related work in the field.

• Open/close Distributed configuration management using composite objects and constraints

  T Coatta and G Neufeld 1994 Distrib. Syst. Engng. 1 294 Tag this article

  Article References Full text PDF (819 KB)

  Distributed programming has transformed applications into federations of cooperating components. Complex interactions between such components create complex interdependencies which are outstripping the capacity of systems managers to monitor and control them. Furthermore, adding configuration management features to an application's components reduces flexibility and portability. The Raven Configuration Management System (RCMS) addresses these problems by handling configuration management orthogonally to the task of programming components. RCMS groups related components together, and provides rules which govern their interactions. RCMS combines object-oriented structuring with declarative programming to improve reliability and performance in the presence of an evolving environment. An initial version of RCMS has been completed, including a compiler and run-time support routines.

• Open/close Implementing configuration management policies for distributed applications

  Gerald Krause and Martin Zimmermann 1996 Distrib. Syst. Engng. 3 86 Tag this article

  Article References Full text PDF (376 KB)

  The central purpose of this paper is to present a novel framework supporting the specification and the implementation of configuration management policies for distributed applications. The introduced approach is part of a system called PRISMA (A platform for integrated construction and management of distributed applications). It provides an integrated application development environment comprising of a distributed application model, a specification language and several design, implementation and management tools. To reduce management complexity, we introduce a technique which permits the definition of configuration management policies as an integral part of an application specification. A configuration management policy is composed of one or more instantiation rules and termination rules for component creation and termination, and event-driven reconfiguration rules.

• Open/close Types and their management in open distributed systems

  Wayne Brookes et al 1997 Distrib. Syst. Engng. 4 177 Tag this article

  Article References Full text PDF (303 KB)

  Open distributed processing aims to support cooperation within and between large-scale heterogeneous and autonomous computing environments. An inherent issue in such environments is enabling the interoperation of objects whose interfaces have been defined in different type models. In this paper, we present a type management system which provides a means for representing, storing, retrieving and translating types, and for expressing and evaluating relationships between types in a heterogeneous distributed computing environment. This system allows multiple type languages and models, and can relate types expressed in different ones. The type management system is designed to support the instantiation and dynamic binding of objects, run-time type checking of object interactions, and the discovery of new resources (e.g. services) within the system.

  Current approaches to interface definition in distributed systems are mainly based on the use of a single interface definition language (IDL). While this provides a level of common agreement about the types of system interfaces, the type models of existing IDLs are not rich enough to model either the overall architecture of a system or the behaviour of objects. We illustrate this by briefly describing some aspects of an enhanced type model with the emphasis on the model's impact on the design of the type management system.