Globus plug-in for WINGS Wokflow Engine C. de Alfonso 1 , M. Caballer 1 , V. Hernández 1 , E. Martí 1 1 Grid and High Performance Computing Research Group, Instituto ITACA - Universidad Politécnica de Valencia email: [calfonso,micafer,vhernand,emarti]@itaca.upv.es phone: (+34) 963877007 ext. 88254, fax: (+34) 963877274 Abstract In a previous work [1] has been described WINGS, a workflow engine focused on multi-grid capabilities and easy extensibility. WINGS engine has been developed using a modular architecture. Every element is implemented as a plug-in, so new elements can be added without the need of modifying the other parts of the system. In the first version of the workflow engine, the Fura [2] middleware plug-in was developed to test the system functionality. In this case, a Globus Toolkit plug-in has been developed to enable multi-grid tests. The Globus plug-in has been implemented because it is likely to be used in a great number of current infrastructures that use it as the underlying grid middleware (EGEE, EELA, etc.). This plug-in enables the access to an important amount of resources. In this paper the Globus Toolkit (pre-ws) plug-in is described, focusing on the generalisation of its concepts to be interoperable in the WINGs multi-grid architecture. 1 Introduction Despite that Grid technology has become a powerful tool for scientists, porting applications to a Grid environment involves a hard work, because it is still handmade. One of the main problems is the approach of porting the application. The approach of porting an existing application to the Grid consists in creating a new application which artificially packages data as a long-running task, instead of the natural already existing medium-running tasks. In many cases, the algorithms are also re-coded (which need more time and may lead to errors, bugs, etc.). These long tasks are exposed to the common job cancellations, execution errors, job aborts and removal from the queue, etc. Despite that the medium tasks are also exposed to these events, the impact of reinitialization of a long job in the whole execution is more appreciable. So using shorter tasks increases the efficiency in the usage of the resources, and lowers the impact of the re-scheduling of tasks. The usage of workflows for grid application porting is limited because it is hard to find a proper workflow engine, which fits the specific application, the dependence of data, movements of information, coordination, iteration, etc. That is probably because many engines have been developed under the influence of wider scope projects. This paper summarizes the general purpose workflow engine and language WINGS (which stands for Workflow in New generation Grid Systems), and describes how its concepts and architecture cover the use cases of Globus Toolkit.