Overview of Software Processes

Overview of Software Processes

• A software process consists of structured activities for developing a software system.
• Core activities include:
  • Specification: Defining system requirements.
  • Design & Implementation: Organizing and coding the system.
  • Validation: Ensuring it meets customer needs.
  • Evolution: Adapting the system to changing requirements.

Software Process Descriptions

• Process descriptions encompass activities, their sequence, and:
  • Products: Outcomes of process activities.
  • Roles: Responsibilities of individuals in the process.
  • Pre/Post-conditions: True statements before and after activities.

Plan-Driven vs. Agile Processes

• Plan-driven processes involve detailed advance planning with progress monitored against this plan.
• Agile processes feature incremental planning, allowing adjustments based on customer feedback.
• Most practical approaches blend elements of both methodologies, with no universally 'correct' process.

Software Process Models

• Various models exist for software processes:
  • Waterfall Model: Linear phases; stages of specification and development are distinct.
  • Incremental Development: Activities are interleaved; can be plan-driven or agile.
  • Integration and Configuration: Assembles systems from existing components; approaches can vary.

Waterfall Model Phases

• Phases include:
  • Requirements analysis and definition
  • System and software design
  • Implementation and unit testing
  • Integration and system testing
  • Operation and maintenance
• The model’s inflexibility makes changes challenging once a phase is complete, limiting its effectiveness for dynamic requirements.

Waterfall Model Limitations

• Difficult to accommodate change due to rigid stage separation, making it best for stable requirements.
• Most applicable in large systems engineering, where a structured approach aids coordination across multiple sites.

Incremental Development Benefits

• Lower costs for adapting to changing requirements compared to the waterfall model.
• Encourages customer feedback through demonstrations and early delivery of functional software.
• Facilitates rapid deployment, allowing customers to use software sooner.

Incremental Development Challenges

• Lack of visibility in process can hinder management’s ability to track progress without regular deliverables.
• Possible degradation of system structure over time without adequate refactoring, complicating future changes.

Integration and Configuration

• Focuses on software reuse, integrating existing components or commercial-off-the-shelf (COTS) systems.
• Reusable items can be configured to meet specific user needs, with reuse becoming standard in many business applications.

Types of Reusable Software

• Stand-alone COTS applications can be configured for specific environments.
• Packages of objects developed for integration with frameworks like .NET.
• Web services following industry standards for remote access.

Reuse-Oriented Software Engineering

• Key stages include:
  • Requirements specification and refinement
  • Software discovery and evaluation
  • Application system configuration
  • Component adaptation and integration

Advantages & Disadvantages of Reuse

• Cost reduction and lowered risks by minimizing custom development.
• Faster system delivery but may involve compromising on user requirements.
• Potential loss of control over the evolution of reused components.

Process Activities

• Software processes interweave technical, collaborative, and managerial activities aimed at developing software.
• The organization of specification, development, validation, and evolution activities differs across methodologies, with the waterfall model following a strict sequential order versus interleaved in incremental development.

This quiz covers the fundamental concepts of software processes, including specification, design, validation, and evolution. It also discusses the differences between plan-driven and agile methodologies, highlighting the benefits of blending both approaches for effective software development. Test your understanding of the core activities and roles involved in software processes.