This is the SimGrid project. This file is a bit outdated, sorry. There is at least 5 sub-projects in the tree: - XBT: eXtended Bundle of Tools (low-level toolbox: logging, datatypes). - SURF: a SimUlation aRtiFact. This is the simulation kernel. - MSG: originally MetaSimGrid, MSG is a simple distributed application simulator. - GRAS: Grid Reality And Simulation (message passing API with two implementations allowing to compile programs on top of the simulator or for the real life without code modification) - AMOK: Advanced Metacomputing Overlay Kit (high level toolbox; Grid application elements such as distributed database, topology discovery service, and so on) More informations are available in the doc/ directory. In particular, don't forget to read the FAQ in there. It probably contains the answer to your question ;)