Software Maintenance and Evolution Quiz

Software Evolution

• Software evolution is the process of developing software initially, then updating it over time for various reasons.
• It involves adding new features, removing outdated functionalities, or adapting to changing circumstances.
• Key activities include change identification, proposal, analyzing changes, release planning, implementing the change, and releasing the updated system.

Software Maintenance

• Software maintenance is the general process of changing a system after it's delivered.
• This includes correcting errors, adapting it for new environments, upgrading functionality, and other tasks.
• There are three main types: corrective, adaptive, perfective, and preventive maintenance.

Problems During Maintenance

• Maintenance problems are significant factors
• Increasing maintenance costs as software continues to be modified
• Errors in the original software architecture
• Degraded software structures
• Lack of clear documentation

Types of Maintenance

• Corrective maintenance: Fixing bugs or errors in the software.
• Adaptive maintenance: Adapting the software to a changed environment (e.g., new hardware, operating system).
• Perfective maintenance: Enhancing the software's functionality or performance.
• Preventive maintenance: Improving the software's future maintainability (e.g., improving code structure, adding documentation).

Software Maintenance Process

• Phase 1: Determine the objective: Determining exactly what needs to be changed.
• Phase 2: Program understanding: Understanding the existing code and its relationship with other parts of the system.
• Phase 3: Proposal: Preparing a detailed plan for the change.
• Phase 4: Account for ripple effect: Consider potential unintended consequences the change might have for other elements.
• Phase 5: Testing: Thoroughly testing the changes to ensure no new issues were introduced.
• This iterative process seeks to effectively address the issue without degrading the operational capabilities of the existing system.

Maintenance Costs

• Maintenance costs often exceed development costs significantly, sometimes by a factor of 2 to 100 depending on the complexity of the application.
• Factors include technical issues, non-technical factors (lack of documentation, staff skills), age of software, and its structure.

Maintenance Prediction

• Maintenance prediction aims to identify parts of a system likely to cause issues.
• Techniques predict parts of the system that are most prone to errors.
• This helps prioritize maintenance efforts, focusing resources on potentially critical elements.

Software Re-Engineering

• Software re-engineering is concerned with improving existing software (legacy systems) by re-implementing to enhance maintainability without changing its functionality.
• It involves activities like re-documentation, restructuring, translation, migrating to a new platform, and graphically displaying design information and re-documenting the system.

Re-engineering Process Activities

• A well-defined re-engineering process outlines a series of tasks to be performed when working with legacy systems.

Advantages of Re-Engineering

• Reduced risk of problems compared to building a new system.
• Lower initial investment, often significantly less expensive than developing a brand-new software.

Re-engineering Cost Factors

• The quality of the existing software.
• The tools available for re-engineering.
• The extent of any data conversion needed.
• Availability of qualified staff with suitable expertise.