Computational grids are complex structures designed to offer high quality, high throughput computing resources in a distributed environment linking sites in a world-wide geographical area. Grid computing and infrastructures are part of several reasearch projects. Europe participates to grid reasearch and deployment by financing the European DataGrid (EDG) project in which a great effort is spent by high energy physics institutes and researchers expecially CERN and INFN (at least to the author's knowledge). For a more detailed and in depth information, check the reference section and connect to the web sites.
Grid computation is a challenging project with the aim of creating an extremely powerful computing system made of commodity computers sharing resources at several sites in a world-wide network. The project requires the most advanced technologies in computation, databases, monitoring, networking, security and authentication, etc.
The present software release has already reached a stage in which production jobs may run with a success rate that depends on workload and available resources. Therefore we expect that future releases will make of grid computation one of the main tools for data processing of next generation high energy physics experiments.
The aim of the present report is to introduce end users to grid computing showing at the samne time how easy is job running and how complex is the job handling process.
This report is part of a documentation set ,  intended for end users as an introduction and a tutorial to Grid services and usage. The document collection is the result of the personal experience of the author and is planned as a guide to user access according to new realeases and software evolution and is kept up-to-date in the limits of the available manpower.
This report is addressed to Grid users with a basic knowledge of terms
and access. For basic information check the introductory documents at:
Check also the official documentation , the collection of terms in glossary form  and the main Web links .