Pass path: Learn the phases of Waterfall SDLC, differences between Waterfall and Agile, and Spiral risk quadrants. Top path: Evaluate Scrum sprint ceremonies, analyze throwaway vs evolutionary prototyping, and justify model selection criteria.
Part 1: Core Concepts (2 Marks)
★ Systems Development Life Cycle (SDLC): A structured sequential or iterative engineering framework guiding an enterprise through the planning, analysis, design, implementation, and maintenance of information systems. ★ Waterfall vs Agile: Waterfall is a linear-sequential model where each phase must be signed off before the next begins, suited for fixed, stable requirements; Agile is an iterative-incremental framework delivering working software in short sprints with continuous stakeholder feedback. ★ Prototyping (Throwaway vs Evolutionary): Throwaway prototyping builds a mock-up to clarify ambiguous user requirements and discards it prior to system build; Evolutionary prototyping starts with a minimal functional core and incrementally refines it into the final production system.
Part 2: Structural Frameworks (10 Marks)
SDLC Methodologies: Traditional Waterfall vs Modern Agile Scrum
- Traditional Waterfall Phases:
- Requirements Specification: Exhaustive gathering of business/technical needs; signed off in SRS.
- System Design: Architecture, entity-relationship diagrams, interface mockups, schema design.
- Implementation / Coding: Software construction in targeted programming language.
- Testing & Quality Assurance: Unit testing, integration testing, system testing, acceptance testing.
- Deployment & Maintenance: Production rollout, bug patching, adaptive updates.
Waterfall vs Agile Framework Diagram
- Agile Scrum Lifecycle & Ceremonies:
- Artifacts: Product Backlog (prioritized user stories), Sprint Backlog, Burndown Chart.
- Sprints: 2-to-4 week fixed time-boxes producing potentially shippable product increments.
- Ceremonies: Sprint Planning, Daily Scrum (15-min standup), Sprint Review (demo), Sprint Retrospective.
- Roles: Product Owner (defines value), Scrum Master (removes blockers), Development Team.
Part 3: Distinction Tables
| Criteria | Waterfall SDLC | Agile Scrum |
|---|---|---|
| Process Approach | Linear-sequential, plan-driven | Iterative-incremental, value-driven |
| Requirement Flexibility | Inflexible; change requests incur severe cost | Highly flexible; changes welcomed throughout |
| Customer Involvement | Heavy at start (requirements) and end (UAT) | Continuous collaboration throughout every sprint |
| Working Software Delivery | Delivered only at end of total project lifecycle | Shipped incrementally at end of each 2-4 week sprint |
| Risk Profile | High late-stage risk of failure | Low risk; early failure detection and fast pivot |
Part 4: Worked Problems & Exam Traps
- Easy: Why is Boehm’s Spiral Model described as a “risk-driven” process?
- Answer: Because each loop/cycle of the spiral begins with explicit risk identification, risk analysis, and risk mitigation before proceeding to architecture or coding.
- Exam-level: An enterprise client wants to build a mission-critical banking core with strictly mandated central bank regulatory compliance. Which SDLC model is appropriate?
- Answer: The Waterfall or V-Model is best suited because requirements are rigidly defined by law, documentation and audit trails are paramount, and architectural changes cannot be accepted arbitrarily midway.
- Twist variant: Does Agile eliminate the need for software documentation?
- Answer: No. Agile Manifesto values “working software over comprehensive documentation”, meaning documentation should be lightweight and valuable, not completely eliminated.
Students lose marks here because they describe Agile as an unstructured coding approach without planning, failing to mention the strict discipline of Sprint time-boxes, backlogs, and retrospectives.