1. …building the next IT revolution From Web to Grid…

2. Around 1990, CERN, along with a few other particle physics labs, constituted the entire World Wide Web. The Web was designed at CERN to facilitate exchange of information between scientists working on different computers, perhaps at different sites. The UK played a leading role in these developments. The Web is mainly aimed at the exchange of information while the Grid is concerned with the exchange of computer power, data-storage, and access to large databases, without forcing users to search for these resources manually. Once connected to the Grid, the end user will see it essentially as one large computer system. The Grid is a practical solution to the data-intensive problems that must be overcome if the computing needs of many scientific communities and industry are to be fulfilled over the next decade. UK Physicists are currently preparing for the Large Hadron Collider (LHC) that will turn on in 2007 at CERN and produce an enormous stream of data (PetaBytes per year) that must be stored and processed (using up to 100 thousand processors). Because no single computer centre is able to provide for both the storage and computing facilities for the entire LHC operation, distribution of computation and data are essential. The UK expects to play a major role in the analysis of data from the LHC and the exciting discoveries that may result. UK Physicists are also participating in a number of US-based experiments that are already producing data. Although not yet on the scale expected from the LHC, these experiments are being used to test the Grid developments as a practical tool for doing real analysis today. The GridPP Project www.gridpp.ac.uk GridPP is a collaboration of Particle Physicists and Computing Scientists from the UK and CERN, who are building a Grid for Particle Physics. There are three main developments within GridPP: Grid software (middleware); Grid-enabled applications; and,provision of computing infrastructure in the UK and CERN. GridPP will enable testing of a prototype Grid for the LHC project of significant scale, and provide resources for the LHC experiments ALICE, ATLAS, CMS and LHCb. The GridPP project is designed to integrate with the existing Particle Physics programme within the UK including the US-based experiments BaBar, CDF and D0. Prototype middleware is being developed in the UK as part of the EU DataGrid project and is illustrated by: 1. OPTOR which optimises requests for replicated data, starting from peer to peer protocols; 2. R-GMA used to access information services essential to Grid operation; and 3. GridSite used to update the GridPP central web service using Grid certificate authentication. Application development is illustrated by: 1. BaBar - monitoring, data location, job submission and job retrieval are integrated into a system to analyse physics data. 2. LHCb - distributing computing and storage resources are used to generate and monitor Monte Carlo simulation data. The infrastructure for the LHC experiments is organised in a tier structure emanating from CERN (Tier-0). This prototype structure is illustrated by: 1. The RAL Tier-1 centre; and 2. ScotGRID, as an example of a Tier-2 centre. GridPP is funded by PPARC and via HEFCE, SHEFC and the EU