I learned Fortran from ancient people who disregard modern standards. As such, my code consists mainly of that older syntax. I am wondering how well this meshes with current Fortran environments, specifically regarding double precision calculations. This comes up mainly because I have been told that real*8 and similar declarations should be abandoned in favor of KIND. For example, in the following code section Code (Fortran): real*8 x,y,z x=12.3456 y=2*x z=2.d0*x will y maintain full double precision, or will a statement like z be required? Similarly, if the fractional nature of the initial variable is defined only implicitly, Code (Fortran): real*8 pi,y,z pi=4*atan(1) y=2*pi z=2.d0*pi does this change the nature of y or z? Or, for that matter, does pi maintain an appropriate value here instead of being declared as pi=4.d0*atan(1.d0)? Thanks.