SDLC Activities
- Requirements → Design → Implementation → Testing → Deployment → Maintenance
- Quality is built in via reviews, traceability, and V&V throughout.
ASCII Map
Requirements ──► Design ──► Coding ──► Testing ──► Deploy ──► Maintain
▲ │ │ │ │
└──────────────┴───────────┴───────────┴────────────┘ feedback
Phase Deliverables
| Phase | Key Activities | Deliverables |
|---|
| Requirements | Elicit, analyze, prioritize | Vision, SRS, RTM |
| Design | Architecture, detailed design | HLD, LLD, UML diagrams |
| Implementation | Code, unit tests | Source, build artifacts |
| Testing | Plan, design, execute tests | Test plan, cases, reports |
| Deployment | Release packaging, rollout | Release notes, runbooks |
| Maintenance | Bug fixes, enhancements | Change logs, patches |
Verification vs Validation
| Aspect | Verification | Validation |
|---|
| Question | Are we building the product right? | Are we building the right product? |
| Focus | Compliance to specs | User needs and fitness |
| Methods | Reviews, walkthroughs, static analysis | Testing, UAT, pilots |
| Timing | Throughout | After integration/near release |
Process Models
- Waterfall: Linear phases, simple control; risky for changing requirements.
- V-Model: Testing activities mapped to each development phase.
- Incremental/Iterative: Develop in increments; feedback refines scope.
- Spiral: Risk-driven cycles: plan → risk analysis → engineering → evaluation.
V-Model (ASCII)
Requirements ───────────────► Acceptance Test
│ ▲
System Design ───────────────► System Test
│ ▲
Detailed Design ───────────────► Integration Test
│ ▲
▼ │
Coding ─────────┘ Unit Test
| Model | Best When | Pros | Cons |
|---|
| Waterfall | Stable requirements | Simple, predictable | Late feedback, rigid |
| V-Model | Safety/regulated domains | Traceable testing | Heavyweight |
| Incremental | Staged delivery | Early value | Architecture drift risk |
| Spiral | High uncertainty/risk | Risk management | Complex to manage |
Agile Overview
Values: individuals, working software, collaboration, response to change. Practices: Scrum, Kanban, XP.
- Deliver in small increments with continuous feedback.
- Prioritize highest-value items first; embrace change.
Scrum in Practice
- Roles: Product Owner, Scrum Master, Developers
- Events: Sprint (2–4 weeks), Planning, Daily Scrum, Review, Retrospective
- Artifacts: Product Backlog, Sprint Backlog, Increment (DoD)
User Story Template
As a <role> I want <feature> so that <benefit>.
Acceptance Criteria: Given/When/Then ...
Model Selection Guide
- Volatile requirements → Iterative/Agile
- High risk/uncertainty → Spiral with risk analysis
- Compliance/traceability → V-Model
- Short project, clear scope → Waterfall
Quick Revision
- V vs VnV: Verification = build right; Validation = build right thing.
- Waterfall pros: simple; cons: late feedback. Agile flips that.
- Traceability: SRS ↔ design ↔ code ↔ tests.