MIPSpro Power Fortran 77 is a Fortran 77 compiler that enables you to run Fortran 77 programs efficiently on Silicon Graphics multiprocessor systems including CHALLENGE, Onyx, POWER CHALLENGE, and POWER Onyx. Power Fortran 77 analyzes a program, identifies loops that are safe to execute concurrently on parallel CPUs, and generates a parallel version of the program automatically. The Fortran 77 manual, MIPSpro Fortran 77 Programmer's Guide, describes the special driver options and source directives you can use to explicitly control parallel execution, and the environment variables used to regulate parallel execution at run time. This Guide documents the driver options and source directives used to achieve automatic parallelization of an unmodified Fortran 77 program.