He has been using and developing PETSc since 1997. Dave A. May is a senior research fellow in the Department of Earth Sciences at the University of Oxford. He has been using PETSc since 2002 to develop scalable HPC software for studying geodynamic processes. Jed Brown is an assistant professor of computer science at the University of Colorado, Boulder. He has been a PETSc user since 2003 and a developer since 2008. Barry Smith is a senior computational mathematician in the Mathematics and Computer Science Division at Argonne National Laboratory. He has been developing PETSc since 1991.