DEC says the Open MP parallel programming interface – see Top Stories section – will be used to write programs for shared memory systems but thinks MPI and Posix threads will still be used to write software for clustered for distributed SMP systems. It says the majority of vendors supporting Open MP previously had their own, slightly different ways of writing programs at a higher level than MPI or threads and that Open MP unifies them, improving portability and the ability of ISVs to target multiple platforms. As well as unifying various parallel programming mechanisms, the vendors have added extensions which allow more flexibility and finer-grain detail. Some vendor-specific functionaility, such as directives that Silicon Graphics Inc implements to deal with latency inherent in its ccNUMA architecture have not been implemented in Open MP. An initial draft of the operating system-independent specification has been submitted to a recently-created Open MP council, full details of which are expected to be made public at the forthcoming Supercomputing ’97 show in San Jose, California. DEC says it will allow companies to build systems with supercomputer-type performance using off-the-shelf components. It says Open MP is currently bneing added to the compilers it supplies for use on its systems. The Kuck & Associates Inc-inspired Parallel Computing Forum led to the creation of an X3H5 ANSI committe which investigated a common parallel programming API but never concluded its work. Kuck’s work and other pioneering development done by Cray Research Inc on microtasking and parallel programming and execution techniques was eventually implemented in slightly different forms by a variety of vendors. DEC, IBM, Intel, Kuck and SGI eventually agreed to combine the two approaches into Open MP.
