All of the CMAQ programs (with the exception of M3BLD) are written in FORTRAN and are optimized for use on computers running a version of the UNIX operating system. Most personal computers (PC’s) running the Linux operating system are sufficiently powerful to handle basic CMAQ applications. However, to use CMAQ in a production environment where multiple iterations of the model will be executed for different spatial domains and/or emissions control strategies, either a cluster of multi-processor PC’s on a high-end network or an expandable rack-mounted UNIX server is recommended. In light of the dynamic nature of the computer hardware world, the specifications listed in the section are current recommendations, not requirements. While there are minimum levels of processing power and disk capacity needed for running CMAQ, there is no single system that CMAQ is optimized to run on. The flexibility of the modeling system enables the users to optimize CMAQ for most current hardware configurations.

CMAQ is distributed and supported for executing on Red Hat Linux operating systems with the Portland Group Fortran compiler. Ports have been made to other brands of Linux such as Mandrake and Suse, to other Fortran compilers, such as Absoft and Intel, and to other hardware systems such as Sun, Silicon Graphics, and Macintosh. Information about these ports and up-to-date hardware recommendations are able through the CMAS Center website (http://www.cmascenter.org/). The hardware recommendations provided below are the minimum level required to run CMAQ, these certainly can be expanded to more powerful and larger systems with benefits to the model performance. The software recommendations are closer to requirements as all of the necessary source code libraries and utilities needed for running CMAQ are listed.