There are now three versions of FACSIMILE. The Windows version is supplied with the front-end which is described in the FACSIMILE section of this site. Other versions are available for Linux and MAC OS X and comprise the core FACSIMILE integrator accessed from the command line rather than the Windows front-end. All versions use the same modelling language.
FACSIMILE for Windows
Uses a graphical front-end. Can be licensed either with a file based system or a USB hardware key.
Read more here.
FACSIMILE for MAC OS X
Runs from the command line on OS X 10.5 or greater on Intel® systems. Allows user to use own tools for model preperation and data analysis. Generally runs faster than the Windows version on similar hardware. Licensed by a hardware key.
Read more here