New Fortran Features: The Portable Use of Shared Memory Segments

The latest version of the Fortran standard, Fortran 2003, introduces many new features. While full compilers are not yet available, many have now implemented one of the most important new features, a portable method for Fortran to interoperate with C. This allows access from Fortran to many features of the OS that were previously the domain of the systems programmer. In this report I show how shared memory segments and semaphores can be used to both enable HPC applications to solve bigger problems and to solve those problems more quickly. I illustrate these points with an example using the GAMESS-UK electronic structure code. This is a Technical Report from the HPCx Consortium. Report available from http://www.hpcx.ac.uk/research/hpc/technical_reports/HPCxTR0701.pdf © UoE HPCx Ltd 2007 Neither UoE HPCx Ltd nor its members separately accept any responsibility for loss or damage arising from the use of information contained in any of their reports or in any communication about their tests or investigations. New Fortran Features: The Portable Use of Shared Memory Segments 2