[GRASS-user] Fortran DOS programs and GRASS GIS

[Dimos]

Hello All,

Best wishes from Greece.

A short question (I have no software development
experience, so please bare with me): 

I am working with a 1-dimensional model: 
which is written in Fortran
has available source code
runs on windows as a DOS program
provides output (plant growth, pollution etc) in one
dimension.

I would like to make a spatial, grid based use of it.
So, how could I:

Use the exisitng fortran code in Linux ( or the DOS
file)
Create a grid with the input values
run the program on a per-grid basis
have output written back to the database or grid

While searching on the GRASS GIS mailing lists, I have
seen some comments on using r.mapcalc for similar
situations.

Anyway, it would be a great halp if someone can
recomend a step by step method to develop this.

Thanks, Dimos