its documentation , and an extensive suite of test cases. The test suite illustrates how to use the code, its range of validity, and includes embedded monitors that confirm that the code is operating correctly. All previously released versions of  are available on the web site, with most stored in an openly accessible *Subversion* repository. The distribution is subject to a BSD style license.

Although this is the first major review since F98,  has been continuously developed, as witnessed by the papers cited above. New versions are released every two to three years, at the conclusion of a period of development which focused on particular aspects of the simulations. This is the seventh major release since F98. The [[](http://www.nublado.org)]{} site gives the full history.

At the time of F98, the code was $\sim 9\times 10^4$ lines written in Fortran 77, with some portable extensions. It transitioned to C in 1999 and C++ in 2006. Today  consists of roughly $2.1\times 10^5$ lines of C++ source code. In recent years, the size of the code has stabilized, as work to extend its scope is balanced by the move from the inclusion of physics data within the source coding towards the use of 