The Second-system effect or sometimes, more euphoniously, second-system syndrome is when one is designing the successor to a relatively small, elegant, and successful system, there is a tendency to become grandiose in one's success and design an elephantine feature-laden monstrosity. The term was first used by Fred Brooks in his classic The Mythical Man-Month. It described the jump from a set of nice, simple operating systems on the IBM 70xx series to OS/360 on the 360 series. A similar effect can also happen in an evolving system; see Brooks's Law, creeping elegance, creeping featurism. See also Multics, OS/2, the X Window System, software bloat.


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