Comment by ajxs

I've worked at organisations which have mainframe applications that have been running for almost 50 years. One of the funnier reasons I've heard about why these '100k lines of COBOL' programs never get rewritten is that no one really knows the full extent of what they do, and even if they do know the full extent of what they do, no one really knows the full extent of why. The business requirements that these programs cover are long since lost, but the program still remains. Even if this isn't a 100% true anecdote, it's an amusing one.