The effort required to conduct a Fortran migration depends largely on the answers to the following questions:
1. Is the code modular?
Modular the code, easier and more convenient is programmer’s job. That’s why is better to understand the FORTRAN code. First and foremost one should understand the call sequence, commons and data structure.
2. Will platform-specific code need migration within Fortran?
Understanding the code will lead you to see if there is platform specific features links calls to some OS specific features. understand them, find alternatives to them. Are they really needed? Can they be substituted with something else?
3. What third-party libraries will Fortran code need and are these compatible with your target platform?
If there are 3rd party libraries like MSC Nastran Access, you need to know are they available in your target platform. How good they are supported. Are they compatible with the OS and the development studio that you are going to use.
4. Is the Fortran module calling any non-Fortran language function/module?
Is the program pure FORTRAN only program or is it a mixed language program. Understanding the link and how are what the different language are doing is essential. which variables and data is being passed through needs to be checked.
5. What is the version of the Fortran compiler?
What standard of FORTRAN are you dealing with. The lower the standard, the more the effort. Fortran 66 will have lot of goto’s, statement numbers etc. The higher the standard the source program is written in the better be the modularity of the program.
6. Is GUI or graphics support required?
Most FORTRAN are GUI less, and plot ASCII graphs. Things to consider, if they are still needed or better or some additional external graphics libraries can be used.