• Computational Grid Environments & Security (Thursday 1:30-3:00PM)
    Room A201/205
    Access Grid Enabled
    Chair: Satoshi Matsuoka, JIT, RWC, Japan

    • Title: Supporting Efficient Execution in Heterogeneous Distributed Computing Environments with Cactus and Globus
    • Authors:
      Gabrielle Allen (Max Planck Institute for Gravitational Physics)
      Thomas Dramlitsch (Max Planck Institute for Gravitational Physics)
      Ian Foster (Argonne National Laboratory)
      Nick Karonis (Northern Illinois University)
      Matei Ripeanu (University of Chicago)
      Edward Seidel (Max Planck Institute for Gravitational Physics)
      Brian Toonen (Argonne National Laboratory)
      Gordon Bell Prize Finalist
    • Abstract:
      Improvements in the performance of processors and networks make it both feasible and interesting to treat collections of workstations, servers, clusters, and supercomputers as integrated computational resources, or Grids. However, the highly heterogeneous and dynamic nature of such Grids can make application development difficult. Here we describe an architecture and prototype implementation for a Grid-enabled computational framework based on Cactus, the MPICH-G2 Grid-enabled message-passing library, and a variety of specialized features to support efficient execution in Grid environments. We have used this framework to perform record-setting computations in numerical relativity, running across four supercomputers and achieving scaling of 88% (1140 CPU's) and 63% (1500 CPUs). The problem size we were able to compute was about five times larger than any other previous run. Further, we introduce and demonstrate adaptive methods that automatically adjust computational parameters during run time, to increase dramatically the efficiency of a distributed Grid simulation, without modification of the application and without any knowledge of the underlying network connecting the distributed computers.

    • Title: Optimisation of Component-based Applications within a Grid Environment
    • Authors:
      Nathalie Furmento (Department of Computing, Imperial College)
      Anthony Mayer (Department of Computing, Imperial College)
      Stephen McGough (Department of Computing, Imperial College)
      Steven Newhouse (Department of Computing, Imperial College)
      Tony Field (Department of Computing, Imperial College)
      John Darlington (Department of Computing, Imperial College)
    • Abstract:
      Effective exploitation of computational grids can only be achieved when applications are fully integrated with the grid middleware and the underlying computational resources. Fundamental to this exploitation is information. Information about the structure and behaviour of the application, the capability of the computational and networking resources, and the availability and access to these resources by an individual, a group or an organisation.
         This paper describes an integrated grid environment that is open, extensible and platform independent. We match a high-level application specification, defined as a network of components, to an optimal combination of the currently available component implementations within our grid environment. We demonstrate the effectiveness of this architecture through high-level specification and solution of a set of linear equations by automatic and optimal resource and implementation selection.

    • Title: Adapting Globus and Kerberos for a Secure ASCI Grid
    • Authors:
      Patrick C. Moore (Sandia National Laboratories)
      Wilbur R. Johnson (Sandia National Laboratories)
      Richard J. Detry (Sandia National Laboratories)
    • Abstract:
      Porting a complex secure application from one security infrastructure to another is often difficult or impractical. Grid security associated with the Globus toolkit is supported by a Grid Security Infrastructure (GSI) based on a Public Key Infrastructure where users authenticate to the grid using X509 certificates. Kerberos security is based on a trusted third party, secret key infrastructure where users authenticate using encrypted tickets. However, both GSI and Kerberos provide a Generic Security Services Application Program Interface (GSSAPI) for source code portability. We describe the porting of our Globus system from GSI security to Kerberos V5 security, and the Kerberos modifications necessary to achieve that portability. Our case study provides details and insights that will be of value to developers and designers interested in GSSAPI portability. We conclude, based on our results, that designers of network security software should strive to accommodate the GSSAPI.