In the article, “Reasoning About Software Quality Attributes” at http://www.sei.cmu.edu/architecture/reasoning_about.html author identified five important quality attributes for software architecture “modifiability, performance, availability, security and usability”. Of course, those are important ones but in practice architecture solve a business need, which may force to focus on one or two from above list and sacrifice other ones.

The statement “this quality attribute is important for the system” valid if it conform to the goal/s of system.

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