Logical layers within n-tier systems should be designed to interact and be
influenced by neighboring layers only. This restriction is often violated,
to the detriment of the system. In this article I will discuss why this is
common, the consequences, and why we should focus on layer isolationism.

http://www.codeproject.com/useritems/TierPressure.asp

--
Chad Z. Hower aka Kudzu
"Programming is an art form that fights back"

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