Low-level programming of parallel supercomputers

It is suggested that, while high-level-language and OS abstractions have evolved gradually and intelligently over the years with respect to single-instruction, single-data stream machines, these abstractions should not necessarily be provided in early generations of parallel supercomputers. Experience with low-level programming must precede the definition and evolution of abstractions for such machines. Future systems will naturally evolve to the correct level of abstraction, but experimentation with current machines must proceed as much as possible at levels that allow direct examination and evaluation of machine characteristics. Further, new software and hardware techniques should be developed to provide services that will be necessary, such as secure access to multiuser devices