Classic Waterfall model in Software Engineering

Summary

In this educational video, the classical waterfall model in software development is explained, highlighting its linear, sequential phases: feasibility study, requirement analysis, design, coding, testing, and maintenance. The video emphasizes its simplicity and suitability for small projects with fixed requirements. However, it also points out its rigidity, lack of flexibility, absence of parallelism, and high risk due to late feedback, often resulting in a significant maintenance phase where most issues are addressed.

Takeaways

• 😀 Classical Waterfall model was introduced in the 1970s and is a very old model.
• 😀 It is called a 'waterfall' because the steps are sequential, like a waterfall.
• 😀 The model includes phases such as feasibility study, requirement analysis, design, coding, testing, and maintenance.
• 😀 Feasibility study ensures the project is viable technically and financially.
• 😀 Maintenance is the most important phase as it requires around 60% of the effort.
• 😀 The Waterfall model is rigid; once a phase is completed, it cannot be revisited.
• 😀 It works well for small projects where the customer's requirements are clear and fixed.
• 😀 Lack of feedback between phases is a major disadvantage of the model.
• 😀 There is no parallelism, meaning one phase must be completed before the next can start.
• 😀 High risk is associated with the Waterfall model because issues are only identified in the final stages.

Q & A

What is the classical waterfall model?

The classical waterfall model is an old software development model from the 1970s, characterized by a linear and sequential approach where each phase must be completed before the next one begins.

Why is it called the 'waterfall' model?

It is called the 'waterfall' model because the phases in the process are depicted in a diagram that resembles a waterfall, flowing in a systematic way from one phase to the next without looping back.

What are the main phases of the classical waterfall model?

The main phases of the classical waterfall model include feasibility study, requirement analysis, specification design, coding and unit testing, system testing and integration, and maintenance.

What is the purpose of the feasibility study in the waterfall model?

The feasibility study determines whether a project is feasible, considering technical and financial aspects, ensuring that the project can be completed within the given budget and resources.

Why is the waterfall model considered rigid?

The waterfall model is considered rigid because it does not allow for changes once a phase is completed and the process moves to the next phase, lacking flexibility and feedback mechanisms.

What are the advantages of using the classical waterfall model?

The advantages of the classical waterfall model include its simplicity, systematic approach, and suitability for small projects with clear and fixed requirements.

What are the disadvantages of the classical waterfall model?

The disadvantages include its rigidity, lack of flexibility, absence of parallelism, high risk due to the late identification of issues, and the need for a significant amount of effort in the maintenance phase.

Why is the maintenance phase considered very important in the waterfall model?

The maintenance phase is crucial because it is where most of the effort (up to 60%) is spent fixing problems and bugs that were not identified in earlier phases due to the model's rigidity.

How does the waterfall model handle changes in requirements?

The waterfall model does not handle changes in requirements well, as it is designed to move forward through phases without looping back, making it difficult to incorporate changes after the initial requirements phase.

What is an example given in the script to illustrate the problems with the waterfall model?

The script uses the example of building a dream house where the customer does not see the progress until the end, leading to late discovery of issues like a small kitchen or misplaced bedroom, which then require costly and time-consuming changes during the maintenance phase.