Waterfall Method Concepts

Waterfall Method

The Waterfall Model is a breakdown of project activities into linear sequential phases, where each phase depends on the deliverables of the previous one and corresponds to a specialisation of tasks. The appraoch is typical for certain areas of engineering design. In software development, it tends to be among the less iterative and flexible approaches, as progress flows in largely one direction through the phases of conceptionm, initiation, analysis, design, construction, testing, deployment, and maintainence.

This model originated in the manufacturing and construction industries; where the highly structured physical environments meant that design changes became prohibitively expensive much sooner in the development process. When first adopted for software development, there were no recognised alternatives for knowledge-based creative work.

Waterfall Model Diagram

We will focus on these points on the Waterfall Model:

The Six Stages
Advantages
Disadvantages

The Six Stages

Implementing a waterfall model oriented project is a rather straight forward process, this is due to the step by step nature of the method itself. There are minor differnecess in the numbers and descriptions of the steps involved in a waterfall method, depending on the developer you ask. Regardless, the concepts are all the same and encompass the broad scope of what it takes to start with an idea and develop a full-scale, live application.

Requirements - During this initial pase, the potential requirements of the application are methodically analyzed and written down in a specification documet that serves as the basis for all future development. The result is typically a requirement document that defines what the application should do, but not how it should do it.
Analysis - The system is analyzed in order to properly generate the models and business logic that will be used in the application.
Design - This stage largely covers technical design requirements, such as programming language, data layers, services etc.
Coding - Finally you get to actually start coding! This includes implementing all models, business logic, and service integrations that were specified in the prior stages.
Testing - During this stage, QA, beta testers, and all other testers systematically discover and report issues within the application that need to be resolved. It is not uncommon for this phase to cause a repeat of the previous coding phase in order for revealed bugs to be properly squashed.
Operations - Finally, the application is ready for deployment to a live environment. The operations stage entails not just the deployment of the application, but also subsequent support and maintenence that may be required to keep it functional and up to date.

Advantages

While the waterfall model has seen a slow phasing out in recent years in favour of more agile methods, it can still provide a number of benefits, particularly for larger projects and organisations that require te stringest stages and deadlines available within these cool, cascading waters.

Adapts to Shifting Teams - Using the WM (Waterfall Mode) does allow the project as a whole to maintain a more detailed, robust scope and design structure due to all the upfront planning and documentation stages. This is suited to larger teams and it may see members come and go thoughout the development life cycle of the project, allowing the burden of design to be placed on the core documentation and less on any individual team member.
Forces Structured Organization - This WM forces the project and even the organisation building said project, to be extraordinarily disciplined in its design and structure. Most sizable projects will, by necessity, include detailed procedures to manage every aspect of the project, from design and development to testing and implementation.
Allows for Early Design Changes - The WM lends itself well to alterations early in the life cycle. This is great when fleshing out the specification documents in the first couple stages with the development team and clients, as alterations can be made immediately and with minimal effort, since no coding or implementation has actually taken place up to that point.
Suited for Milestone-Focused Development - Due to the inherent linear structure of a waterfall project, such applications are always well-suited for organizations or teams that work well under a milestone and date focused paradigm. With clear, concrete, and well understood stages that everyone on the team can understand and prepare for, it is relatively simple to develop a time line for the entire process and assign particular markers and milestones for each stage and even completion. This isn't to suggest software development isn't often rife with delays (since it is), but waterfall is befitting the kind of project that needs deadlines.

Disadvantages

While some things in software development never change, many others often fall by the wayside. Over the 40 years of the Waterfall Model being in existence, it has developed some cracks, and some newer methodologies have taken form. Below are the disadvantages with the Waterfall Model:

Nonadaptive Design Constrains - The WM has an inherent lack of adaptability across all stages of the development life cycle. When a test in stage 5 reveals a fundamental flaw in the design of the system, it not only requires a dramatic leap backward in stages of the process, but in some cases, can be often lead to a devastating realization regarding the legitimacy of the entire system. While most experienced teams and developers would argue that such revelations shouldn't occur if the system was properly designed in the first place, not every possibility can be accounted for, especially when stages are so often delayed until the end of the process.
Ignores Mid-Process User/Client Feedback - Due to the strict step-by-step process that the WM enforces, another particularly difficult issue to get around is that user or client feedback that is provided late into the development cycle can be often be too little, too late. This can be time consuming and costly.
Delayed Testing Period - While most of the more modern SDLC models attempt to integrate testing as a fundamental and always-present process throughout development, the WM largerly shies away from testing until quite late into the life cycle. This not only means that most bugs or even design issues wont be discovered until very late into the process, but it also encourages lackadaisical coding practices since testing is only an afterthought.

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