Jonas Lindemann

An extendable GRID application portal

To attract users from a wide range of scientific areas it is important to provide a variety of ways to access the Lunarc resources. Providing good user interfaces for all categories of users is a key factor for a high use of resources. One way of doing this is by providing access to common applications through a web-based portal. Existing grid portals are often geared towards providing access to the features of the middleware instead of providing interfaces to existing applications. Lunarc has adopted a more application oriented approach providing dedicated user interfaces for each application using the grid middleware as an infrastructure for the implementation. The users as application experts can extend the portal themselves using an easy to use software development kit (SDK) for plugins.

Using CORBA middleware in finite element software

Distributed middleware technologies, such as CORBA can enable finite element software to be used in a more flexible way. Adding functionality is possible without the need for recompiling client code. Applications and libraries can expose their functionality to other applications in a language neutral way, enabling a more direct and easy transfer of data, without the need for intermediate input and output files. The CORBA software components can be easily configured and distributed transparently over the network. A sample structural mechanics code, implemented in C++ is used to illustrate these concepts. Some future directions, such as placing CORBA enabled finite element software on HPC centres are also discussed.

Performance of the NorduGrid ARC and the Dulcinea Executor in ATLAS Data Challenge 2

This talk describes the various stages of ATLAS Data Challenge 2 (DC2) in what concerns usage of resources deployed via NorduGrids Advanced Resource Connector (ARC). It also describes the integration of these resources with the ATLAS production system using the Dulcinea executor. ATLAS Data Challenge 2 (DC2), run in 2004, was designed to be a step forward in the distributed data processing. In particular, much coordination of task assignment to resources was planned to be delegated to Grid in its different flavours. An automatic production management system was designed, to direct the tasks to Grids and conventional resources. The Dulcinea executor is a part of this system that provides interface to the information system and resource brokering capabilities of the ARC middleware. The executor translates the job definitions recieved from the supervisor to the extended resource specification language (XRSL) used by the ARC middleware. It also takes advantage of the ARC middlewares built-in support for the Globus Replica Location Server (RLS) for file registration and lookup. NorduGrids ARC has been deployed on many ATLAS-dedicated resources across the world in order to enable effective participation in ATLAS DC2. This was the first attempt to harness large amounts of strongly heterogeneous resources in various countries for a single collaborative exercise using Grid tools. This talk addresses various issues that arose during different stages of DC2 in this environment: preparation, such as ATLAS software installation; deployment of the middleware; and processing. The results and lessons are summarized as well. (Less)

Interoperating AliEn and ARC for a Distributed Tier1 in the Nordic Countries

To reach its large computing needs, the ALICE experiment at CERN has developed its own middleware called AliEn, centralised and relying on pilot jobs. One of its strength is the automatic installation of the required packages. The Nordic countries have offered a distributed Tier-1 centre for the CERN experiments, where the job management should be done with the NorduGrid middleware ARC.

Using CORBA Middleware in Finite Element Software

Distributed middleware technologies, such as CORBA can enable finite element software to be used in a more flexible way. Adding functionality is possible without the need for recompiling client code. Transfer of data can be done directly, without the need for intermediate input and output files. The CORBA software components can be easily configured and distributed tranparently over the network. A sample structural mechanics code, implemented in C++ is used to illustrate these concepts. Some future directions, such as placing CORBA enabled finite element software on HPC centres are also discussed.

Real-time visualisation of fibre networks

Different methods of real-time fibre-network visualisation have been studied. Using an extrusion-based method yields very good results, but for large networks the frame rate becomes unacceptably low. To increase the number of fibres that can be visualised in real time, a textured billboard method has been implemented. With this method, an average performance gain of 60% has been achieved, using an OpenGL implementation.