Flashback to 1985, when this Cobol programmer pilot fish is handed an old, large program he’s never seen before — but he already knows it’s going to be trouble.
“It had been modified many times,” says fish. “I was told to figure out why the most recent changes caused the program to miscalculate some figure.
“The program started off with the usual housekeeping processes, including a line that read PERFORM REPORT-HEADINGS THRU REPORT-HEADINGS-EXIT. I saw no need to verify the report headings, so I moved on into the meat of the program.
“After a few days, I realized I was totally lost in the code. The program didn’t appear to be doing what I had been told the program did. I was forced to turn on tracing to try to figure out what the program was doing.