Waterfall Model
The Waterfall Model in software engineering is one of the earliest approaches to software development. It follows a strict linear sequence where each stage must be completed before moving to the next. While it is simple and well-structured, it also has several limitations that modern methodologies attempt to solve.
What Is the Waterfall Model?
The Waterfall Model is a sequential software development process. It was first introduced in 1970 by Dr. Winston Royce. The model is called “waterfall” because progress flows in one direction, similar to a waterfall, without going back to previous phases.
Key Stages of the Waterfall Model
The development life cycle under this model usually includes:
- Requirement Analysis – Collecting and documenting all project requirements.
- System Design – Creating architecture and design based on requirements.
- Implementation (Coding) – Writing the actual source code.
- Testing – Detecting and fixing errors.
- Deployment & Maintenance – Delivering the final product and handling updates.
Advantages of the Waterfall Model
- Clear structure and easy to understand.
- Detailed documentation at every stage.
- Works well when requirements are stable and well-defined.
- Suitable for small-scale projects.
Disadvantages of the Waterfall Model
- Very rigid: it is difficult to go back once a phase is complete.
- Changes during development are expensive and time-consuming.
- Errors are often discovered late in the testing phase.
- Not ideal for complex or evolving projects.
Modified Versions of the Waterfall Model
Over time, modified versions such as the Iterative Waterfall Model were introduced. These allow limited feedback loops between stages, making the process more flexible and reducing risks compared to the original model.
When to Use the Waterfall Model?
The Waterfall Model works best when:
- Project requirements are clear and unlikely to change.
- The project is small or medium in size.
- Use the waterfall model if Documentation and process control are highly important.
Conclusion
The Waterfall Model in software engineering remains a foundational method for understanding structured software development. However, its rigidity makes it less suitable for modern projects with rapidly changing requirements. In such cases, more flexible models like Agile or Spiral may provide better results.
