Classical Waterfall model | Software Engineering

What is Waterfall Model in Software Engineering?

• The Classical Waterfall Model, also known as the Traditional Waterfall Model, is a linear and sequential approach to the software development life cycle.
• The Waterfall Model is one of the earliest and most straightforward methodologies used in software engineering.
• The Waterfall model is a simple approach to SDLC where each step flows downwards like a waterfall.
• In the Classical Waterfall Model, the software development process is divided into distinct phases, and each phase must be completed before moving on to the next. The phases are typically:

Phases of Classical Waterfall Model

• Requirements Gathering and Analysis
• System Design
• Implementation
• Testing
• Deployment
• Maintenance

Requirements Gathering and Analysis

• In this initial phase, the project team gathers and documents all the requirements for the software product.
• In this step, the project team talks to the people who want the software (like customers or users) to understand what they need the software to do.
• The project team gathers all their requirements and creates a detailed list.

System Design

• Once the requirements are fully understood, the system design phase begins.
• We design the overall structure of the software and decide how different parts will work together.

Implementation

• In the implementation phase, developers write the actual code for the software based on the detailed design specifications.
• This is where the software is built according to the design.
• Developers write the code according to the design and turn the plans into a real working program.

Testing

• After the code is complete, the software goes through a testing phase.
• Different types of testing, including unit testing, integration testing, and system testing, are performed to ensure that the software functions as expected.

Deployment

• Once testing is successful, the software is deployed or released to the end-users or customers.

Maintenance

• After deployment, the software enters the maintenance phase, where updates, bug fixes, and enhancements are made as needed throughout its lifecycle.
• This step involves taking care of the software even after it's been deployed to ensure it continues to work well.

When to use SDLC Waterfall model?

• Well-Defined Requirements: When the project requirements are clear, stable, and unlikely to change significantly during development.
• Low-Risk Tolerance: In situations where the project stakeholders have a low tolerance for risk and prefer a predictable approach.
• Small to Medium-sized Projects: It works well for relatively small to medium-sized projects with manageable complexity.
• Strict Regulatory Compliance: In industries where strict regulatory compliance is essential, such as healthcare or finance, Waterfall's documentation-heavy approach can be advantageous.
• Projects with Fixed Scope: When the project scope is well-defined and not expected to change significantly over time.

Why use Waterfall model?

• Clear Requirements: When project requirements are well-defined, stable, and unlikely to change significantly during development.
• Predictability: It offers a predictable and structured approach to software development, making it easier to plan, schedule, and budget projects.
• Documentation: Waterfall places a strong emphasis on documentation at each stage, which can be valuable for maintaining a clear project history.

Advantages of Waterfall Model

• Structured Approach: Provides a systematic and well-defined approach to software development.
• Clear Deliverables: Well-documented requirements and design specifications lead to clear deliverables.
• Client Involvement: Client expectations are set early, reducing the likelihood of scope changes.

Disadvantages of Waterfall Model

• Rigidity: Limited adaptability to changing requirements or customer feedback.
• Longer Time to Deliver: This can be time-consuming, especially for large projects.
• Risk of Customer Dissatisfaction: Clients may not see the product until the late stages, increasing the risk of misalignment with expectations.

Conclusion