Software Architecture

Software Architecture

1. This chapter focus in

   • Understand the general concept of architecture
   • Understand different views to the concept of software architecture
   • Understand the notion of software architectural styles
   • Understand the roles of software architecture and architectural styles in software design

2. The notion architecture

   • The main function of the system is the most important and basic factor and determines its structure
   • STORED PROGRAM: The data and the instructions are both stored in the main memory
   • SEQUENTIAL EXECUTION: Instructions are executed from one intruction to the next in the order of their locarion in memory
   • The primary function of the CPU is to execute the instructions fetched from the main memory

3. The notion of software architecture

   • A diagram abstracts from a complicated system provides a comprehensible representation of the system to facilite reasoning about the system
   • Prescriptive models
     • Data elements are those that contain the information that is used and transformed
     • Processing elements are those components that supply the transformation on the data elements
     • Connecting elements are the 'glue' that holds the different pieces of the architecture together
     • The relationships are used to constrain the 'placement' of architectural elements
     • Properties are used to constrain the choice of architectural elements
     • The weight are the set of properties and relationchips that together define the minimum desired contrains on the software architecture
   • Descriptive models
     • Components, that are a unit of software that performs some function at run-time
     • A connector is a mechanism that mediates communication coordination

4. Software architecture Style

   • Not all types of components can appear in a software architecture because this limits the types of components that can be incluided in the system
   • Connectors are mechanisms that mediate communication, coordination or cooperration among components
   • A software architecture also limits the choices of the topological structure that components are interconnected through connectors
   • In adition to the limitations imposed on components, connectors and topological structures, software architecture may also impose semantic constraints at a system level