Abstract

Introduction
In this work, we present a current status of development and integration of Migrating Desktop and corresponding grid tools. Migrating Desktop (MD) is an advanced GUI, which allows working with grid resources, it hides the complexity of the grid middleware and frees the user from knowing where the resources physically reside. This facility is not only a gui for well-known Globus commands, it offers much more: flexible personalised working environment, scalability and portability, set of tools, single sign-on mechanism, Roaming Access Server (RAS) interfaces, support for multiple grid infrastructure. The more detailed outline is described here.

The Migrating Desktop overview
A number of Grid middleware projects are currently working on user interfaces for interaction with grid
applications, however due to the dynamic and complex nature of the Grid, efficient job submission and job management is still difficult to ordinary scientists. Through its user- and application-centric approach, the Migrating Desktop brings new quality to High Performance Computing (HPC) user interfaces. Our solution is a complete, production-deployed software environment with special focus on interactive grid applications. These applications are simultaneously compute- as well as data-intensive and are characterized by the interaction with a person in a processing loop. This research was done under the EU CrossGrid project (IST-2001-32243). The homepage of the Migrating Desktop encloses the tool, and user guide [3]. Migrating Desktop is just a front end to Remote Access Server, which intermediates between different grid middleware and applications. The RAS offers a well-defined set of web-services that can be used as an interface for accessing HPC systems and services (based on various technologies) in a common, standardized way. All communication bases on web services technology. This architecture provides an important future direction with respect to the general acceptance of services and protocols. General concept of MD was to provide the containers - frameworks for plug-ins written by application developers. Such approach allows increasing functionality in an easy way without need of architecture changes.

It is possible to add various tools, applications and support visualisation of different formats using that mechanism. As an example: MD on demand loads from network appropriate plug-in for visualisation of nonstandard graphics format file. That makes our product independent of specialized tools designed only for specific application. MD supports different kinds of accessing remote/HPC applications. We have focused mainly on supporting frameworks for grid applications, unifying different interfaces into one common solution. MD calls appropriate web services on the RAS. The server job submission interface gives uniform access to different resource brokers. Clients can submit all jobs with this interface and then appropriate plug-ins are called to convert job description to the specific language. Currently we are using plug-in for CrossGrid/DataGrid resource broker to convert job description to JDL and Progress plug-in to convert job description to XRSL. Grid
applications available for users are grouped in a user-friendly way in a Job Wizard in the MD. This Wizard simplifies the process of specifying parameters and limits, suggesting user defaults or recently used parameters.

The Wizard is responsible for proper preparation of the user's job and consists of several panels. One panel is application specific plug-in and the rest can be used to set job information, resource requirements, files and environment variables. Application plug-in asks user for application parameters and these parameters are passed to the command line later on. For application developers that do not like to prepare plug-in we created generic XML plug-in that interprets argument description given in XML to a graphical form. Example of plug-ins is MD also allows running remote Java tools. In contrast to grid applications that are submitted to the resource broker, tools are Java applets downloaded from different network localisations on demand. Some applications require a graphical visualisation of job results. In our approach visualisators are tools and they also
base on the Tool Plug-in.

Migrating Desktop bases on Java applet technology. It can be launched using Java Webstart Technology or using web browser with appropriate Java Plugin included in Java Runtime Environment (JRE). We base on Swing libraries for designing graphical user interface, Java CoG Kit [4] version 1.1a with some extensions is being used as interface to Globus functionality and Axis ver. 1.1 web services client for communication with Roaming Access Server. As an server for webservices we use open-source servlet container, Apache Tomcat version 4.1. During the presentation, the live demo of the Migrating Desktop will be presented. The preliminary view of this framework, as a current status of work is available [2].

References
1. M. Kupczyk, R. Lichwala, N. Meyer, B. Palak, M. Plociennik, P. Wolniewicz, „Mobile Work Environment
for Grid Users", Across Grids 2003, LNCS 2970, pp. 132-138, 2004
2. http://ras.man.poznan.pl/crossgrid/md1.avi
3. http://wp3.crossgrid.org
4. G. von Laszewskia, I. Foster, J. Gawor, and P. Lane, .A java commodity grid kit,. Concurrency and
computation: Practice and Experience, vol. 13, no. 8-9, pp. 643.662, 2001, http://www.cogkits.org/.