Alliant Computer Systems Corporation manufactures two computers, called the FX/8 and the FX/1, that process individual scientific and engineering applications at speeds of 0.5 through 23 megaflops on standard benchmarks. Speeds exceeding 60 megaflops are possible on actual problems. The computers, which operate efficiently in an interactive time-sharing environment, support a 4.2BSD Berkeley UNIX-based  operating system and a custom Fortran compiler. The FX/8 and FX/1 use the same basic components, but the FX/8 permits much larger configurations, employs a system cache, and implements the concurrent application of multiple processors to individual programs.A brief overview is presented of the FX/8 computer and the supporting software. Discussed next is the theoretical background for the concurrent use of multiple processors on individual programs. The operation of the FX/8 on Fortran DO loops is then explained. Finally, the theoretical and actual performance of the computer is discussed, and some conclusions are drawn.