The TRACK module consists of a set of routines that allows to track a segmented path through a 3D toroidal plasma and finds the intersections with a set of magnetic flux surfaces. The module requires geometry information, which can be provided through an MHD equilibrium interface. The AJAX and XPLASMA interface subroutines are included in the module. The module comes with configure utility, which creates makefiles for user specific UNIX system and Fortran compiler. The makefiles have options to build two drived programs prvided and to run test cases, included in the module.
I tested the module under Intel Redhat Linux, Sun Solaris, IBM AIX, and SGI IRIX systems without problems. One potential problem of using 64-bit Fortran compilers is related to the different treatment of double precision in TRACK and XPLASMA. This potential problem is properly documented in the module manual.
The distribution comes with a README file, describing installation of the module. An extensive pdf documentation is supplied together with the Fortran source files. The detailed comments are also included in the Fortran source files.
During the review process the original submission has been improved to provide a more readable and portable code.
The general standards, documentation standards, and data standards have been met.