A parallel computer based on simple DSP modules

This article reports on an engineering project at the TUHH aimed at providing a massively parallel experimental computer system to support a number of research projects. The computer nicknamed the PENTAGON is an MIMD system containing a number of identical processing elements (PE's) linked via interfaces. The network is a 3-D torus, and the nodes are based on off-the-shelf signal processor chips, namely TMS 320C40's from TI. The design adds to these standard ingredients an engineering discipline to keep things as simple as possible, and a corresponding, quite unusual physical setup of the total system. These make up for a very cost effective system showing how simple it may be to build a powerful parallel machine.

Although based on a standard architecture, the PENTAGON design takes some special choices, the most important being the complete distribution of I/O capabilities. This provides for an unlimited I/O bandwidth, the support of realtime applications and excellent capabilities of expansion. A graphics interface has been designed to provide direct realtime output from the DSP's. Another recent extension is a set of Power-PC modules on top of the DSP nodes.

Besides standard commercial compilers for 'C40 networks, the functional language Fifth of the author has been implemented on the PENTAGON. Fifth provides facilities such as distributed objects and the automatical distribution of parallel programs. For well parallelizable applications such as the calculation of a Mandelbrot set, high efficiencies in the usage of the processors have been obtained.