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What’s the Difference Between Architecture and Design. Paul Clements Subrahmanyam Allamaraju. Architecture and Design. All architecture is design NOT all design is architecture Architect draws the boundary between architectural and non-architectural design. Traits of the Software Architect.
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What’s the Difference Between Architecture and Design Paul Clements Subrahmanyam Allamaraju
Architecture and Design • All architecture is design • NOT all design is architecture • Architect draws the boundary between architectural and non-architectural design
Traits of the Software Architect • Gained enough breadth and depth in the relevant domain • Strong communication/development/debugging skills • “cross domain and technology proficiency and appreciation” • “knowledge of patterns in domain/technology areas” • Looking for challenging problems • In summary: SUPER ENGINEER
What is Software Architecture? • Represents the structure of the software • Expressed using certain views • Includes principles behind the design and evolution of the software • Essential characteristics of architecture: • High level view • Realize ALL the use case scenarios • Present a systemic view to all stakeholders
Examples of Architectures(all of these are incomplete) • High level Design • Only contains the implementer’s view of the software • Deployment • Concerns how software is deployed across various platforms • Generic Technology Architectures • Examples: COM, CORBA • Does not address the domain the software must exist and evolve in
Survival and Evolution • Software survives as long as it meet the requirements for which it was built • Software must evolve to meet future requirements • Software Architecture’s fundamental requirement: “design a structure for the software considering the long-term consequences”
Architecture ParadoxSurvival vs Evolution • There is pressure on successful to change • New requirements • Changing environment • Software must evolve to survive • Changes increase the entropy of the software • Changes eventually increase the entropy to a point to where further changes are impossible • Software cannot evolve, therefore cannot survive
How to defy the Software Paradox • Identify the goals of the architecture • Discover the principles based on the goals • Design an architecture integrating these principles
Identify the goals of architecture • best-case requirements • long term organizational focus • reuse considerations • User wish lists • Other anticipated changes
Goals to principles • “discover” the principles the software must follow to meet its goals • Principles will guide designers to find the “right” implementation • Principles may be expressed as rules • DOs and DONTS • Enforcing these principles is difficult
Integration of Principles and Architecture • Remove the human element from enforcement of principles • Software structure will dictate: • How the software will be changed • What changes are possible • What changes are not possible
Summary • Software can defy the architecture paradox if: • The structure can accommodate changes • A set of architecture goals is abstracted • Devise a set of principles to realize the goals • Integrate the principles into the architecture