GRID COMPUTING IN THE SCEC COMMUNITY MODELING ENVIRONMENT

In our work on the Southern California Earthquake Center Community Modeling Environment (SCEC/CME) Project (Jordan et al., 2003), we are developing computer systems to support dynamic distributed scientific collaborations. Scientists participating in SCEC collaborations are often willing to share their computer resources, particularly if in return they can gain access to computing capabilities that they do not currently possess. Interorganizational computer sharing can be difficult to achieve due to the many organizational and technical differences between groups. Recently, however, a new software technology called grid computing (Foster et al., 2001) has emerged which is designed to help dynamic organizations, such as SCEC, share heterogeneous collections of computer and storage resources. Grid technology enables organizations to share computer resources with other organizations even when the shared computers are administered differently and have dissimilar hardware and operating systems. Organizations can create a grid environment to provide their users with computer resources such as CPU cycles, disk storage, and software programs that are available outside of their local computer administrative domains. This is done by creating a new computer administrative domain referred to as a virtual organization (VO). A VO has its own set of administrative policies that represents a combination of local computer policies, the computer policies of the groups you are sharing with, plus some administrative policies required by the VO itself. When we run a program on the “grid”, we are saying, in a sense, that our program is running outside of our own local administrative domain. Grid middleware is used to facilitate the execution of computer programs in a VO. In addition to creating multiorganizational administrative domains, grid middleware also strives to hide the heterogeneity of the shared computing environment. Grid software provides a set of commands to perform basic computing operations, and these commands are the same regardless …