William Gropp is Director of the Parallel Computing Institute and Thomas M. Siebel Chair in Computer Science at the University of Illinois Urbana-Champaign. Torsten Hoefler is Assistant Professor of Computer Science at ETH Zurich. Rajeev Thakur is Deputy Director in the Mathematics and Computer Science Division at Argonne National Laboratory. Ewing Lusk is Argonne Distinguished Fellow Emeritus at Argonne National Laboratory.