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SDLC Models Notes

Questions

3-4 questions per semester paper

Difficulty

Medium

Importance

High yield for Software Engineering and System Analysis papers

Overview

Software Development Life Cycle (SDLC) models are systematic frameworks used to structure, plan, and control the process of developing an information system. Mastering these models is essential for university exams as they form the foundational methodology for software engineering projects, emphasizing the transition from requirements to maintenance.

Waterfall Model

The Waterfall model is a linear, sequential approach where each phase must be completed before the next begins. It is highly structured and documented, making it ideal for projects with well-defined requirements that rarely change.

  • Sequential and non-iterative structure
  • Rigid phase-gate documentation
  • High cost of change during later stages
  • Best suited for small, predictable projects
  • Phases: Requirement, Analysis, Design, Coding, Testing, Deployment

Agile and Scrum

Agile is an iterative and incremental approach that focuses on flexibility and customer feedback through short delivery cycles. Scrum, a popular Agile framework, utilizes roles like the Scrum Master and Product Owner to manage work in time-boxed increments called Sprints.

  • Focus on iterative and incremental delivery
  • Customer collaboration over contract negotiation
  • Sprint duration typically 2-4 weeks
  • Key roles: Scrum Master, Product Owner, Development Team
  • Artifacts: Product Backlog, Sprint Backlog, Increment

Spiral and Iterative Models

The Spiral model combines iterative development with the controlled aspects of the Waterfall model, emphasizing risk analysis at every stage. The Iterative model improves upon the design by repeatedly refining versions of the software based on feedback.

  • Risk-driven development process
  • Four quadrants: Planning, Risk Analysis, Engineering, Evaluation
  • Iterative refinement of project scope
  • Ideal for large, mission-critical, and expensive projects
  • Continuous improvement cycle

Exam Tip

Always draw diagrams; an SDLC answer without a flow chart or phase diagram is rarely awarded full marks in university-level examinations.

Common Mistakes

  • Confusing the linear nature of Waterfall with the cyclical nature of the Spiral model.
  • Failing to mention risk analysis as the primary driver in the Spiral model.
  • Overlooking the importance of 'Sprints' and 'Backlogs' when discussing Scrum methodology.

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