The world's most powerful particle accelerator is being constructed at CERN, the European Organisation for Nuclear Research, near Geneva on the border between France and Switzerland. The accelerator, called the LargeHadron Collider (LHC), will start operation in 2007 and be used as a research tool by four large collaborations of physics researchers, including some 6,000 people from universities and laboratories around the world including RMKI in Budapest, Hungary.

The computational requirements of the experiments that will use the LHC are enormous: 5-8 PetaBytes of data will be generated each year, the analysis of which will require some 10 PetaBytes of disk storage and the equivalent of 200,000 of today's fastest PC processors. Even allowing for the continuing increase in storage densities and processor performance this will be a very large and complex computing system, and about two thirds of the computing capacity will be installed in "regional computing centres" spread across Europe, America and Asia.

The computing facility for LHC will thus be implemented as a global computational grid, with the goal of integrating large geographically distributed computing fabrics into a virtual computing environment. There are challenging problems to be tackled in many areas, including distributed scientific applications, computational grid middleware, automated computer system management, high performance networking, object database management, security, and global grid operations.

The development and prototyping work is being organised as a project that includes many scientific institutes and industrial partners, co-ordinated by CERN. The project, nicknamed LCG (after LHC Computing Grid), will be integrated with several European national computational grid activities, and it will collaborate closely with other projects involved in advanced grid technology and high performance wide area networking, such as:

* GEANT, Datagrid and DataTAG, partially funded by the European Union,

* GriPhyN, Globus, iVDGL and PPDG, funded in the US by the National Science Foundation and the Department of Energy.

During the first half of 2003 an initial LCG Global GRID Service (LCG-1) will be set up, with the clear goal of providing a reliable, productive service for LHC collaborations. The service will begin with a small number of the larger Regional Centres, including sites in the three continents.

A GRID Deployment Board (GDB) is created to manage the deployment of LCG. In order to qualify a country for participation in the deployment it implies having an approved plan to contribute to the LCG common infrastructure for April 2003 with at least one centre having a minimum capacity of 50 CPUs and 5 TeraBytes of disk space together with 2FTE's available for operation and support.

In accordance with these requirements in the RMKI the installation of the LCG cluster is in progress and by April it will be incorporated to the system. This cluster however serves only as a seed for wider activities.

The talk will summarise the experience gained in the CERN EU Datagrid project, whose EDG testbed can be regarded as prototype for LCG Phase I.

The planned gradual build-up of LCG till 2007 will be highlighted and the possibilities will be discussed how Hungary can participate in this scientific venture effectively with relatively modest resources and what benefits are expected from this project for the general GRID community. In this respect we should like to emphasise both side of the story: on one hand the deployment of a "working" system, and on the other hand a starting base for research and development base for new applications, upgrade and work out new versions of the system itself.