Computation on Parallel Message-Passing Computers

Within parallel computing, one may divide the present architectures into 3 categories, (a) massively parallel SIMD, (b) Shared memory MIMD and (c) Distributed memory MIMD (or Message Passing). (SIMD = Single Instruction Multiple Data; MIMD = Multiple Instruction Multiple Data). The "simplest" of these is the message-passing architecture. A Message-Passing system consists of several processors, where each processor has a "fair" amount of local memory and is connected to some kind of communication network. This talk covers some of the most common tools of an established parallel message passing operating system, Trollius [1]. One tool, TGraph [2], developed at Bergen Scientific Centre, is a tool for graphics output under X-windows from the processors. A programming philosophy [3] for message-passing computers which is based on `domain decomposition', and some specific applications, such as Wave Equation [4], Gauss Elimination [5] and a large Climate Model project are discussed.