Revision as of 06:29, 19 March 2012

Introduction to Software Architecture

Software architecture encompasses the set of significant decisions about the organization of a software system :
- Selection of structural elements and their interfaces by which a system is composed.
- Behaviour as specified in collaborations among those elements.
- Composition of these structural and behavioural elements into larger subsystem.
- Architectural style that guides this organization.

Definition:
- The structure or structures of the system which comprise of software elements, the externally visible properties of those elements and the relationships among them.

There are different stakeholders (client, user, project manager, developer, maintainer) who want different qualities of the system being built.
E.g. client is concerned about cost, user about usability, project manager about dividing work, developer about implementation and maintainer about making changes.
An architecture provides a framework and structure for airing these concerns.

An architecture constrains implementation.
An architecture can help to determine organisational structure.
Allow apriori reasoning about change.
- Probably the most important - since 80% of software cost occurs after deployment.
- Enables risk assessment of future project changes.
Support analysis and prediction about future properties.

@@ Line 19: / Line 19: @@
 == Capture early design decisions ==
+* An architecture constrains implementation.
+* An architecture can help to determine organisational structure.
+* Allow apriori reasoning about change.
+** Probably the most important - since 80% of software cost occurs after deployment.
+** Enables risk assessment of future project changes.
+* Support analysis and prediction about future properties.
 == Reusable abstraction of systems ==