On Tue, 22 Aug 2017, Alan wrote: > Sometimes a rewrite is a useful and needed thing.
Thanks, Alan, for allowing us to share our obscure bug experiences on this thread. :-) In grad school in 1972 I wrote an ecosystem ecological energy flow model in FORTRAN IV to run on the U. of Illinois' IBM S/360. It used more than a whole box of 80-column Hollerith cards for input. When it ran it produed incorrect results, but only the same 2 or 3 wrong answers each time. So I printed the source code listing on the wide green-bar paper that all the line printers used. The output was about 1 inch thick. I carefully examined each line of code multiple times without seeing the error. Finally, I took the printed listing to the computer center's help desk. They examined it without finding the problem. One day, strictly by chance while looking at a new printed copy (likely done on a printer with a newer ribbon) I saw the error jump up and bite me on the nose. Instead of a loop index written as FOR I = 1 TO N I had mistyped it as FOR 1 = 1 TO N. Distinguishing 1 from the uppercase I was difficult and, because all of us expected to see I and not 1 in that position we all overlooked it. Haven't forgotten this after all these years. Rich _______________________________________________ PLUG mailing list [email protected] http://lists.pdxlinux.org/mailman/listinfo/plug
