XCAT 2.0: A Component-Based Programming Model for Grid Web Services

The most important recent development in Grid systems is the adoption of the web services model as a basic architecture for Grid services. This paper describes a component framework for building distributed Grid applications that is consistent with that model. The framework, called XCAT, is based on the U.S. Department of Energy Common Component Architecture but with an implementation based on the standard web services stack. Using this framework, it is possible for an application programmer to build distributed applications by composing software components running on remote resources. The result is a transient, stateful web service that represents the executing application instance. This paper describes the basic architecture of XCAT and a programming/scripting model for building the composed application services.