Julian Seward was the original founder, designer and author of Valgrind, created the dynamic translation frameworks, wrote Memcheck, the 3.X versions of Helgrind, Ptrcheck, DHAT, and did lots of other things. Nicholas Nethercote did the core/tool generalisation, wrote Cachegrind and Massif, and tons of other stuff. Tom Hughes did a vast number of bug fixes, helped out with support for more recent Linux/glibc versions, set up the present build system, and has helped out with test and build machines. Jeremy Fitzhardinge wrote Helgrind (in the 2.X line) and totally overhauled low-level syscall/signal and address space layout stuff, among many other things. Josef Weidendorfer wrote and maintains Callgrind and the associated KCachegrind GUI. Paul Mackerras did a lot of the initial per-architecture factoring that forms the basis of the 3.0 line and was also seen in 2.4.0. He also did UCode-based dynamic translation support for PowerPC, and created a set of ppc-linux derivatives of the 2.X release line. Greg Parker wrote the Mac OS X port. Dirk Mueller contributed the malloc/free mismatch checking and other bits and pieces, and acts as our KDE liaison. Robert Walsh added file descriptor leakage checking, new library interception machinery, support for client allocation pools, and minor other tweakage. Bart Van Assche wrote and maintains DRD. Cerion Armour-Brown worked on PowerPC instruction set support in the Vex dynamic-translation framework. Maynard Johnson improved the Power6 support. Kirill Batuzov and Dmitry Zhurikhin did the NEON instruction set support for ARM. Donna Robinson did the v6 media instruction support. Donna Robinson created and maintains the very excellent http://www.valgrind.org. Vince Weaver wrote and maintains BBV. Frederic Gobry helped with autoconf and automake. Daniel Berlin modified readelf's dwarf2 source line reader, written by Nick Clifton, for use in Valgrind.o Michael Matz and Simon Hausmann modified the GNU binutils demangler(s) for use in Valgrind. David Woodhouse has helped out with test and build machines over the course of many releases. Florian Krohm and Christian Borntraeger wrote and maintain the S390X/Linux port. Florian improved and ruggedised the regression test system during 2011. Philippe Waroquiers wrote and maintains the embedded GDB server. He also made a bunch of performance and memory-reduction fixes across diverse parts of the system. Maynard Johnson contributed IBM Power6 and Power7 support, and generally deals with ppc64-linux issues. Many, many people sent bug reports, patches, and helpful feedback. Development of Valgrind was supported in part by the Tri-Lab Partners (Lawrence Livermore National Laboratory, Los Alamos National Laboratory, and Sandia National Laboratories) of the U.S. Department of Energy's Advanced Simulation & Computing (ASC) Program.