I am really surprised no one mentioned this, as it was the first thing I thought of. It may very well be the first programming language he learned and for sentimental value s/he added it to his/her name.
When I was getting my first set of degrees in CS and Math we used Fortran for various sets of mathematical modeling. I am fairly young so Fortran isn't something I am well versed in. However, files that are used today are normally written with a .f95 extension to denote the version of Fortran used, opposed to f90 which is older and depreciated and f77 which is very old and never used. If it was his/her first language I would guess s/he is in his 40s-50s.
When I was getting my first set of degrees in CS and Math we used Fortran for various sets of mathematical modeling. I am fairly young so Fortran isn't something I am well versed in. However, files that are used today are normally written with a .f95 extension to denote the version of Fortran used, opposed to f90 which is older and depreciated and f77 which is very old and never used. If it was his/her first language I would guess s/he is in his 40s-50s.