In my experience nearly all standard old code will still compile just fine, except code which relied on compiler-specific extensions and directives. Unfortunate

In my experience nearly all standard old code will still compile just fine, except code which relied on compiler-specific extensions and directives. Unfortunately, there does tend to be a lot of code out there using these proprietary directives. Things like metacommands [0] will need to be converted to something standard (or removed) to work with modern compilers. [0] http://www.ousob.com/ng/fortran/ng4e22.php http://www.ousob.com/ng/fortran/ng4e22.php