Applied Structured Systems Design

Measuring the Design Quality of the System and Software Architecture

Segment Outline:

• Measures of Design Coupling of Structure Charts
• The degree of dependence of one module on another
• Measure of the chance that a defect in one module will appear as a defect in another
• Measure of the chance that a change to one module will necessitate a change in another module
• Cohesion
• Functional Cohesion
• Sequential Cohesion
• Communicational Cohesion
• Procedural Cohesion
• Temporal Cohesion
• Logical Cohesion
• Coincidental Cohesion
• Factoring
• Decision Splitting
• System Shape relative to Module Types
• Afferent Module: Sends information from modules it calls to its caller
• Transform Module: Transforms data it receives from its caller and sends back to its caller
• Efferent Module: Sends information from its caller to modules it calls
• Coordinate Module: Coordinates the communication of modules it calls
• System Balance
• Fan In, Fan Out
• Coincidental Cohesion
• Reporting Errors
• Editing Data Rules
• Data Related Design Considerations
• Additional Design Considerations
• Practical Guidelines