The Cactus software is representative for a whole class of scientific applications; typically those that are tightly coupled, have regular space decomposition, and huge memory and processor time requirements.

The Cactus software package is suitable for a class of scientific applications that are tightly coupled, have regular space decompositions, and involve huge memory and processor time requirements. Cactus has proved to be a valuable tool for astrophysicists, who first initiated its development. However, today's fastest supercomputers are not powerful enough to perform realistic large-scale astrophysics simulations with Cactus. Instead, we must turn to innovative resource environments -- in particular, computational Grids -- to satisfy this need for computational power. Our paper addresses issues related to the execution of applications such as Cactus in Grid environments. We focus on two types of Grids: a set of geographically distributed supercomputers and a collection of one million Internet-connected workstations.

The Cactus software package is representative for a class of scientific applications that are tightly coupled, have regular space decompositions, and involve huge memory and processor time requirements. Cactus has proved to be a valuable tool for astrophysicists, who first initiated its development. However, today’s fastest supercomputers are not powerful enough to perform realistic large-scale astrophysics simulations with Cactus. Instead, astrophysicists must turn to innovative resource environments—in particular, computational grids—to satisfy this need for computational power. This paper addresses issues related to the execution of applications such as Cactus in grid environments. The authors focus on two types of grids: a set of geographically distributed supercomputers and a collection of one million Internet-connected workstations. The