A data flow evaluation system based on the concept of recursive locality*

Abstract

In an attempt to increase the performance of computing machines, there appears to be two main approaches—(1) to use faster components in existing architectures and (2) to design new architectures which are capable of exploiting some form of concurrency. The first approach is inherently limited in that the effects of reduced integrated circuit geometry, new process technology, and new logic families can be expected to increase overall system performance by only a couple of orders of magnitude. While this is initially impressive, it does not allow the desired machine performance projected to be necessary to solve large physics problems, or needed for accurate weather prediction. 16 The second approach, while being a considerably more difficult organizational problem, is inherently unlimited in nature. There are numerous levels at which concurrency can be exploited in digital computers, i.e. multiple data paths, more concurrent realization of low-level circuit functions, overlap and pipeline processing within a single processing element, multiple processors, etc. In developing any new "fast as possible" machine, it is important to attempt to implement all of the above suggestions. However the work reported here will mainly be concerned with solving the problem of how to utilize and organize systems containing large numbers of independent processors.