2.1. Introduction

This chapter contains information that will aid the user in understanding the program architecture of the SAS4A/SASSYS-1 computer code, and the relationship between its modeling concepts and the program logic and data flow. The code structure is described in terms of modules and subroutines, as are the data management features employed to communicate input and calculated data among modules. The contents and organization of input and output files are described, and results from simplified example problems are included and illustrated.