Why does GISS use the line number format for FORTRAN files?
Line number format is the practice of using the first 8 characters of a line to insert line number information in an ‘F8.3’ format. Historically, this is a holdover from the days of the punchcard when all lines required a line number. Subsequently, it was used at GISS to make additions/corrections to files without having to copy the entire rest of the code (the update system). Further refinements have led to functional updates that allow the ‘piggy-backing’ of specific functionality (such as tracer code, or ocean coupling) on top of the underlying model code in a relatively model-version independent way. We have also found it very useful in tracking bugs, notifying users about code changes and referencing in general. In modelE line number format has been replaced by the CVS revision control system and preprocessing options.
