1.3 Architectural Guidelines

Our ideology can be described by the following guidelines

• Do not add new functionality unless an implementor cannot complete a real application without it.

• It is as important to decide what a system is not as to decide what it is. Do not serve all the world's needs; rather, make the system extensible so that additional needs can be met in an upwardly compatible fashion.

• The only thing worse than generalizing from one example is generalizing from no examples at all.

• If a problem is not completely understood, it is probably best to provide no solution at all.

• If you can get 90 percent of the desired effect for 10 percent of the work, use the simpler solution.

• Isolate complexity as much as possible.

• Provide mechanism, rather than policy. In particular, place user interface policy in the client's hands.

From Scheifler & Gettys: "X Window System"