1996 - Entrepreneur
- 2016 - 2017 Co-Founder, CEO. Campaign Storage, LLC.
- 2011 - 2015 Founder, CEO, Parallel Scientific LLC & DocsForce
- 2010 - 2013 Senior Vice President, Chief Software Architect, Fellow Xyratex Inc.
- 2009 - 2010 Founder, CEO, Chairman ClusterStor LLC (acquired by Xyratex)
- 2007 - 2008 Vice President of Lustre, SUN Microsystems
- 2001 - 2007 Founder, CEO, Chairman, Cluster File Systems (acquired by SUN Microsystems)
- 2000 - 2001 Co-Founder, VP Engineering, Mountain View Data, Inc. (assets acquired by NEC and others).
- 2000 - 2001 Storage Architect, Red Hat Inc.
- 2000 - 2000 Chief Architect, TurboLinux
- 1995 - 2000 Co-Founder, CEO. Stelias Computing, Inc. (acquired by TurboLinux).
1996 - Scientist
- 2019 - Visiting Professor of Physics, Oxford University
- 2018 - Visiting Scholar, Center for Computational Astrophysics, Flatiron Institute, NYC
- 2015 - 2017 Visiting Scholar, Pembroke College, Cambridge University
- 2013 - Principal, Braam Research, LLC
- 2007 - 2010 Adjunct Professor Chinese Academy of Sciences
- 1996 - 2005 Senior Systems Scientist (faculty position) School of Computer Science, Carnegie Mellon University
1980 - 1997 Mathematician
- 1992 - 1993 Special Fellowship, Oxford University
- 1992 Visiting Professor, University of British Columbia
- 1991-1997 University Lecturer and Tutorial Fellow (tenured), St. Catherine’s College, Oxford
- 1988-1991 Assistant and (tenured) Associate Professor of Mathematics, University of Utah
- 1987-1990 Junior Research Fellow, Merton College Oxford
- 1987-1990 Christian and Constantijn Huygens Fellow, National Dutch Science Foundation
- 1985 University of Utrecht, Research Assistant
- 1981-1984 University of Utrecht, Teaching Assistant
- 1987 Oxford University DPhil in Mathematics, supervisor Sir Michael Atiyah
- 1984 University of Utrecht MSc in Mathematics, supervisor Prof. J.J. Duistermaat
- 2007 Software Engineering Institute, Carnegie Mellon University - Certified Software Architecture Professional
- 2004 Software Engineering Institute, Carnegie Mellon University - Certified Team Software Process instructor and coach