GRIDKIT: Pluggable overlay networks for Grid computing

A `second generation' approach to the provision of Grid middleware is now emerging which is built on service-oriented architecture and web services standards and technologies. However, advanced Grid applications have significant demands that are not addressed by present-day web services platforms. As one prime example, current platforms do not support the rich diversity of communication `interaction types' that are demanded by advanced applications (e.g. publish-subscribe, media streaming, peer-to-peer interaction). In the paper we describe the Gridkit middleware which augments the basic service-oriented architecture to address this particular deficiency. We particularly focus on the communications infrastructure support required to support multiple interaction types in a unified, principled and extensible manner-which we present in terms of the novel concept of pluggable overlay networks

Designing and Constructing Modifiable Middleware using Component Frameworks

Because of the increasingly diverse and dynamic environments in which they must operate, modern middleware platforms need to explicitly support 'modifiability'. Modifiability should encompass change that is both static and dynamic, small scale and large scale. Also, the process of modification should be flexible, easy to perform and consistency-preserving. To address these needs, a generic component-based modifiability approach is proposed here, and used to build a highly-modifiable middleware framework. The modifiability approach provides design support for building component frameworks (CFs), that is reusable and extensible component architectures that are targeted at specific domains. In the approach, CFs build upon a minimal, technology-independent component model and can be recursively assembled into more complex CFs. The middleware framework - an instantiation of the proposed approach - takes the form of a specific assembly of CFs, each of which addresses a distinct middleware-related concern. This middleware framework supports two styles of modification: First, 'architectural modification' enables large-scale, static changes, such as customising the framework to a new application domain or underlying infrastructure. Second, 'system modification' enables changes that are based on specific customisations of the framework; these changes are smaller in scope (e.g. replacing protocol implementations) but are applicable at both deploy-time and run-time. A prototype implementation demonstrates the feasibility of the approach and framework presented and demonstrates a sufficient degree of supported modifiability

The design of a configurable and reconfigurable middleware platform

It is now well established that middleware platforms must accommodate an increasingly diverse range of requirements arising from the needs of both applications and underlying systems. Moreover, it is clear that to achieve this accommodation, platforms must be capable of both deployment-time configurability and run-time reconfigurability. This paper describes a middleware platform that addresses these requirements. The platform is built using a well-founded lightweight component model, uses reflective techniques to facilitate (re)configuration, and employs the notion of component frameworks to manage and constrain the scope of reconfiguration operations, Importantly, the platform also aims to achieve high performance and a level of standards conformance (e.g., with CORBA and COM). We demonstrate that, despite its high degree of configurability, the platform performs on a par with standard commercial CORBA ORBs

An extensible binding framework for component-based middleware

One of the most significant limitations of current middleware platforms, both commercial and research, is that they typically support only a small, pre-defined, set of fundamental binding types (e.g., remote method invocation). This restriction limits the scope of platforms in that they cannot easily accommodate, or easily be extended to accommodate, richer or more specialised forms of interaction (e.g. events, media streaming, multicast, and many others discussed in the paper). This paper describes a highly extensible, component-oriented framework for the definition and implementation of such binding types. We motivate and specify the framework in detail and evaluate it by providing examples of its use

OpenPING: A Reflective Middleware Platform for Construction of Adaptive Virtual Reality Applications

The emergence of collaborative virtual world applications that run over the Internet has presented Virtual Reality (VR) application designers with new challenges. In an environment where the public internet streams multimedia data and is constantly under pressure to deliver over widely heterogeneous user-platforms, there has been a growing need that distributed virtual world applications be aware of and adapt to frequent variations in their context of execution. In this paper, we argue that the use of structural reflection offers great potential for the design of flexible real-time interactive Distributed Virtual Environments (DVEs)

Applying Component Frameworks to Develop Flexible Middleware

Introduction It is now well established that middleware must accommodate a wide variety of requirements imposed by applications and underlying environments. Moreover, it must be able to absorb both static and dynamic changes in those requirements. The current generation of middleware clearly fails to address this need [1]. To help address such concerns, we believe that middleware should be built according to a component-based architecture by wiring together independently developed components. It is perhaps ironic that while current middleware intends to support the compositional paradigm for building applications, it itself suffers from an inflexible and monolithic approach to development. The benefits of component technology are well known: reusability, extensibility, modularity, understandability, and reduced development costs. However, while component technology permits runtime adaptability and extensibility, it does not by itself guarantee su

A resource adaptation framework for reflective middleware

It is now well established that next generation middleware platforms must facilitate the management of QoS. Supporting resource adaptation is useful for QoS management, but this issue is not adequately addressed by current adaptive and reflective middleware architectures. The paper describes a framework for supporting resource adaptation by providing first-class representation of activities and generic interfaces for inspecting and controlling the resources allocated to activities

Proceedings of the 2007 symposium on Component and framework technology in high-performance and scientific computing

Applying component-based development requires design support in the form of methods, frameworks, and tools. To this end, this paper first proposes a componentisation approach and then applies this approach to re-engineer a numerical application into a component-based application. The paper provides qualitative and quantitative evidence that componentisation has improved the modifiability and reusability of the application without significantly affecting performance