The Software Development Life Cycle (SDLC)
1. The 5 Stages of SDLC
Every software project, regardless of its size, follows these fundamental stages:
2. Common Development Models
The 9618 syllabus requires you to compare the Waterfall, Iterative, and Rapid Application Development (RAD) models.
Waterfall Model
A linear, rigid sequence. You must finish one stage before starting the next.
- Pros: Easy to manage; clear milestones.
- Cons: High risk; difficult to change requirements once started.
Iterative Model
Develops a small part of the system, tests it, and then adds more features in "sprints."
- Pros: Flexible; allows for early feedback.
- Cons: Can lead to "Scope Creep" if not managed well.
3. RAD (Rapid Application Development)
RAD focuses on prototyping and user feedback rather than strict planning. It often uses automated code generation tools and visual designers.
4. Maintenance Types
Once your software is "live" (like your e-consult.co.ke site), you enter the maintenance phase:
- Corrective: Fixing bugs found by users after release.
- Adaptive: Changing the software to work on a new OS or with new hardware.
- Perfective: Adding new features or improving performance to make it better.
This happens during the Analysis stage. It asks: "Can we build it?" based on technical, economic, legal, and time constraints (TELOS). If the answer is no, the project is scrapped before any code is written.