Software Evolution and Change

Software Change

• Inevitable due to emerging requirements, changing environments, system errors, and the need for improved performance.
• Organizations struggle to manage changes within existing software systems effectively.

Importance of Evolution

• Software systems represent significant investments and are critical business assets.
• Maintaining and updating existing software consumes the majority of large companies' software budgets.

Evolution Processes

• Dependent on software type, development processes, and the skill level of the personnel.
• Change proposals drive system evolution and should connect to affected components for cost and impact assessments.

Change Identification and Evolution Processes

• Continuous throughout the system lifecycle, involving various stages of development.

Change Implementation

• Iterative process for designing, implementing, and testing revisions.
• Initial phase may require program understanding, especially when original developers are unavailable.

Urgent Change Requests

• May bypass typical software engineering processes due to critical system faults, unexpected effects from environmental changes, or rapid business adaptations.

Agile Methods and Evolution

• Agile facilitates seamless transition from development to evolution via incremental updates and frequent releases.
• Automated regression testing helps manage changes effectively, with user stories framing new changes.

Handover Problems

• Disparities between agile and traditional plan-based development approaches can create difficulties during the evolution phase.
• Documentation expectations differ, impacting the evolution process when teams are unfamiliar with the agile methodology.

Legacy Systems

• Older systems built on outdated languages/technologies that may rely on obsolete hardware, including broader socio-technical elements.
• Comprise hardware, software, support systems, application data, business processes, and policies.

Legacy System Components

• May include outdated hardware, unsupported software, inconsistent application data, and business processes designed around legacy capabilities.

Legacy System Replacement

• Risky and costly due to incomplete specifications, tight integration with business processes, and potential software delays.

Legacy System Change

• High costs arise from lack of programming consistency, obsolete languages, inadequate documentation, and data issues.

Legacy System Management

• Organizations must strategize on evolving legacy systems by scrapping, maintaining, re-engineering, or replacing them based on quality and business value.

Legacy System Categories

• Strategies vary according to system quality and business value, ranging from scrapping low-value systems to maintaining high-value systems.

Business Value Assessment

• Should involve multiple stakeholder perspectives including end-users, business customers, line managers, IT managers, and senior management.

Software Maintenance

• Involves modifications to a program after deployment, predominantly for custom software, while generic products evolve into new versions.

Types of Maintenance

• Includes fault repairs, environmental adaptations, and modifications for new functionality.

Maintenance Effort Distribution

• Maintenance costs often exceed development costs due to various technical and non-technical factors.

Maintenance Costs

• Typically greater than development costs, influenced by support costs for aging software and increasing complexity.

Exam Tips

• Understand overarching concepts and apply them to practical scenarios for better retention and comprehension.

Chapters Overview

• Topics covered include Introduction, Software Processes, Agile Development, Requirements Engineering, System Modeling, and Software Evolution.

Explore the concepts of software evolution and change in this quiz. It covers key topics such as software maintenance, legacy systems, and the challenges organizations face in managing software changes. Test your knowledge and prepare for exam success!