wen-king@csvax.caltech.edu (Wen-King Su) (11/21/89)
Subject: Re: IPSC Communications In article <7130@hubcap.clemson.edu> brooks@maddog.llnl.gov writes: < It is interesting to note that the orginal message >passing machine at Caltech was proposed as a grid, not a hypercube. The <Computer scientists there thought that hypercubes were prettier at the time >and forced the physicists to learn Grey codes to get their physics problem <mappings done. The message-routing technology available at the time precludes the use of grids. The machine has to make do with a slow store-and-forward routing that uses an 8-bytes at-a-time, interrupt-driven, programed transfer with a 5 megahertz 8086 CPU. Routing on a grid would be unimaginablely slow. The physics wanted grids because their programs at that time fit on a grid and they do not need non-local messages. However, the computer scientists have a broader vision and went with cubes. It is not until we made the first worm-hole message-routing chip and put it to trial in Symult's machines, has grid connectivity for MIMD message-passing machines become a superior alternative. The real problem now is that the term 'hypercube' has been over-sold by the marketing people and many people have been conditioned to believe that cube is the only viable connectivity. /*------------------------------------------------------------------------*\ | Wen-King Su wen-king@vlsi.caltech.edu Caltech Corp of Cosmic Engineers | \*------------------------------------------------------------------------*/