Application Experience with an Implicitly Parallel Composition Language

We describe our experiences with a very high-level parallel composition language (called GLU) that enables rapid construction of parallel applications using sequential building blocks (extracted from existing sequential applications) and their execution on diverse parallel computer systems. GLU is sufficiently rich to succinctly express different forms of parallelism --- from function parallelism to data parallelism and from pipeline parallelism to tree parallelism. We show by example how a typical sequential application can be converted to a parallel one in GLU and executed on different parallel systems. We also show how GLU has been used to convert two widely used, sequentially written, inherently parallel workstation applications --- the make utility and a raytracing system --- to parallel equivalents that can then be run much faster on a network of workstations. 1 Introduction The idea of composing new applications from existing ones is commonplace in various Unix 1 shells in w..