Clustering IBM Enterprise System/3090 computers for parallel execution of FORTRAN programs

Two IBM Enterprise System/3090™ Model 600J computer systems, each with six processors capable of executing vector and scalar instructions, have been connected into a cluster for parallel execution of single FORTRAN programs. The clustering is achieved through a combination of software and hardware. When enabled for parallel execution and allowed to use all twelve processors in the cluster, FORTRAN programs have run as much as 11.7 times faster than when run on a single processor. The combined hardware and software technology is called IBM Clustered FORTRAN. It was achieved by modifying existing technology quickly to provide new capabilities. This paper discusses the modifications and the motivations behind them. It summarizes the performance of several applications executed with Clustered FORTRAN. Finally, it describes how clustering has been used to improve performance in novel ways.