I know Fortran.<p>As to it becoming &quot;more and more expensive to run it&quot;, that kind of depends. Most of that Fortran code isn&#x27;t touched very often. The cost of swapping it out is <i>huge</i>.<p>Swapping it out piecemeal isn&#x27;t as expensive money-wise, but it carries large risk. <i>Should</i> it be ported out? Sure. <i>Can</i> it be, in any reasonable way? That&#x27;s a harder question, and it&#x27;s not as cut-and-dry as you make it sound.