Waterfall Lifecycle (OCR A Level Computer Science): Revision Note

Waterfall Lifecycle

What is the waterfall model?

• The Waterfall Model is a sequential software development process divided into distinct phases

• Each phase must be completed before the next one begins.

Steps in the model

1. Requirement Gathering and Analysis: All possible system requirements to be developed are captured and documented clearly

2. System Design: The requirements are translated into a design. Architects and designers define the overall architecture and identify the main components

3. Implementation: The actual code is written in this phase based on the design documents, turning the system design into a functional program

4. Integration and Testing: All the components and modules are integrated and tested to ensure that the entire system works as expected

5. Deployment: The product is released to the market or handed over to the client. It may involve installation, customization, and training

6. Maintenance: Post-release, the system needs regular maintenance to fix bugs, improve performance, or add new features

The Waterfall Model in Software Engineering

Benefits

• Simple and linear: Easy to understand and follow, with each stage progressing linearly to the next

• Clear stages and milestones: Each phase has specific deliverables and milestones, making progress easy to measure

• Suitable for well-defined projects: Works best when the requirements are clear and unlikely to change during development

Drawbacks

• Inflexible: Changes are difficult to implement once the project has started, as the model doesn't easily allow for revisiting previous stages

• Expensive to fix late problems: If a problem appears later in the development cycle, it can be costly and time-consuming to fix

• Long development cycle: The sequential nature may lead to a longer development time, especially if stages are delayed

Suitability

• The Waterfall Model is most suitable for projects where requirements are well understood and unlikely to change

• It works well when high quality and compliance are essential, and there is a clear understanding of the project's goals and constraints