COBOL references in "The Jargon File"

software rot

Term used to describe the tendency of software that has not been used in a while to lose; such failure may be semi-humorously ascribed to bit rot. More commonly, `software rot' strikes when a program's assumptions become out of date. If the design was insufficiently robust, this may cause it to fail in mysterious ways. Syn. `code rot'. See also link rot.
For example, owing to endemic shortsightedness in the design of COBOL programs, a good number of them succumbed to software rot when their 2-digit year counters underwent wrap around at the beginning of the year 2000.