While great strides have been made in the field of grid middleware technology, difficulties deploying and configuring current grid middleware technologies from an end user perspective have led to many of the people who would benefit most from the technology, namely application scientists, to avoid using it. In response to this we have developed the Application Hosting Environment (AHE), a lightweight, easily deployable environment designed to simplify the way the scientist interacts with the grid. The AHE builds a layer of middleware on top of existing technologies such as Globus, abstracting the details of the particular underlying grid middleware in use. The functionality of the AHE is exposed as web services using the WSRF::Lite toolkit; the user interacts with these services to launch and monitor applications. The resulting system provides a great deal of flexibility, allowing clients to be developed for a range of devices from PDAs to desktop machines, and command line clients which can be scripted to produce complicated application workflows.

This paper specifies an advance reservation and co-allocation protocol for grid computing, and a simple framework for supporting well defined charging models. The protocol supports arbitrary level of nesting, that is a reservation may be to a virtual resource (a set of resources). The work is motivated by the need for advance reservation in the RealityGrid project. However the protocol is a generic protocol that can reserve any type of resource (e.g. clusters, network, and storage) and for any grid project where users need to reserve one or more resources in advance.

The Web services resource framework defines conventions for managing state in distributed systems based on Web services, and WS-notification defines topic-based publish/subscribe mechanisms. We analyze five independent and quite different implementations of these specifications from the perspectives of architecture, functionality, standards compliance, performance, and interoperability. We identify both commonalities among the different systems (e.g., similar dispatching and SOAP processing mechanisms) and differences (e.g., security, programming models, and performance). Our results provide insights into effective implementation approaches. Our results may also provide application developers, system architects, and deployers with guidance in identifying the right implementation for their requirements and in determining how best to use that implementation and what to expect with regard to performance and interoperability.