 In a major attempt to speed up PL/I code to compete with Fortran object code, PL/I F Release 5 does substantial program optimization of DO-loops facilitated by the REORDER option on procedures.A version of PL/I F was released on the TSS/360 timesharing operating system for the System/360 Model 67, adapted at the IBM Mohansic Lab.The IBM La Gaude Lab in France developed "Language Conversion Programs" to convert Fortran, Cobol, and Algol programs to the PL/I F level of PL/I.