The second-system effect refers to the tendency of small, elegant, and successful systems to have elephantine, feature-laden monstrosities as their successors. The term was first used by Fred Brooks in his classic The Mythical Man-Month.[1] It described the jump from a set of simple operating systems on the IBM 700/7000 series to OS/360 on the 360 series.

---

FWIW I hate the posting of a link without describing the content in some way.