Efficient use of a hybrid computer for the solution of a wide variety of problems requires that the computer hardware be complemented by a comprehensive software package. Such software ought to assist not only in the preparation of programs, but in their execution as well. For open-shop operation of a hybrid facility, it is important that a widely- understood high-level procedure-oriented language be made available to users. From a practical point of view, FORTRAN and its various derivatives are the only lan guages satisfying this requirement at the present time. Expansion of a purely digital programming language into a hybrid programming language may be accomplished either by rewriting the processor or by attaching a suitable subroutine library. The software system of the System Simulation Laboratory at the University of Southern Cali fornia furnishes a concrete example of the latter approach.
