The DIRAC (Distributed Infrastructure with Remote Agent Control) project is a complete Grid solution for a community of users such as the LHCb Collaboration. DIRAC forms a layer between a particular community and various compute resources to allow optimized, transparent and reliable usage.
The DIRAC Workload Management system realizes the task scheduling paradigm with Generic Pilot Jobs ( or Agents ). This task scheduling method solves many problems of using unstable distributed computing resources which are available in computing grids. In particular, it helps the management of the user activities in large Virtual Organizations such as LHC experiments. In more details the DIRAC WMS with Pilot Jobs is described here.
This documentation in also available in PDF version