As a part of a research project on the use of workstations for scientific problem solving, the authors embarked in 1982 on a project to design and implement a software development environment, called R/sup n/, for numerical programmers. In addition to providing the usual environment tools - intelligent editor, debugger, database - they designed R/sup n/ to address the three unique aspects of scientific programming: Fortran, software libraries, and efficiency of execution. This article describes R/sup n/, paying particular attention to its role in the compilation process.