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. It described the jump from a set of simple operating systems on the IBM 700/7000 series to OS/360 on the 360 series.

Explanation

Although expressed as a problem of software design, the second-system effect is observable throughout all human design effort. It is somewhat akin to the idea of “fighting the last battle.”

People who have designed something only once before, try to do all the things they “did not get to do last time,” loading the project up with all the things they put off while making version one, even if most of them should be put off in version two as well.

Examples could include DOS to Win95 or Unix to GNU, using a simple metric like source lines of code to mark the difference.

— Wikipedia on Second-system effect

2012.07.21 Saturday ACHK