软件系统设计

What is Software Architecture

Definition 1: The software architecture of a program or computing system is the structure or structures of the system, which comprise software elements, the externally visible properties of those elements, and the relationships among them. [Software Engineering Institute (SEl)]
程序或计算系统的软件体系结构是系统的一个或多个结构，其中包括软件组件，这些组件的外部可见属性以及它们之间的关系。

Definition 2: The fundamental organization of a system, embodied in its components, their relationships，to each other and the environment, and the principles governing its design and evolution. [IEEE 1471 -2000 Recommended Practice for Architectural Description of Software-Intensive Systems]
系统的基本组织，体现在其组件，它们之间的相互关系以及环境以及支配其设计和演进的原则。

Module 与 Component 的区别：

• Module（模块）：是还没有实现的软件部分
• Component（组件）：是已经实现了的软件部分
• Element 包含了 Component 和 Module

Architecture vs. Design

• It’s about software design:
  所有的体系结构都是软件设计，但不是所有的软件设计都是体系结构
  体系结构是设计过程的一个部分
• Other views:
  体系结构是更高层的设计 high-level designs
  体系结构是设计决策的组合 a set of design decisions
• Structure/Organization of the system:
  Elements: components & connectors
  Relationships: static & dynamic relationships
• Properties: elements, groups of elements & overall system