1The Legion Support for Advanced Parameter-Space Studies on a Grid*

Abstract. Parameter-space studies involve running a single application several times with different parameter sets. Since the jobs are mutually independent, many computing resources can be recruited to conduct an entire study in a distributed manner. Parameter-space studies are attractive applications for grids, which are networked collections of computing and other resources. Legion is a grid infrastructure that facilitates the secure and easy use of heterogeneous, geographically-distributed resources by providing the illusion of a single virtual machine from those resources. Legion provides tools and services that support advanced parameter-space studies, i.e., studies that make complex demands such as transparent access to distributed files, fault-tolerance and security. We demonstrate these benefits with a protein-folding experiment in which a molecular simulation package was run over a grid managed by Legion. 1