The waterfall method or System Development Life Cycle Model (SDLC) is a basic popular model used by many software development firms to create a structure in which to start a project or creation. It is a sequential model that flows downward through several phases, which is viewed by persons such as Winston W. Royce to be flawed. Royce had written a paper on how this model could be configured and optimized to be a iterative model, whose internal mechanisms are similar to widely used methods of today. It is still popular, however the term “waterfall” to many has become a way to describe any approach to development that is regarded as “inflexible and non-iterative.”

The Original Model:



Royce's original model was made up of seven phases. Like a cascading waterfall the model flows downward, one phase to the next. When one stage is complete, the next one begins, creating a problem by never applying revision. Often lessons are learned in one stage later on that should be implemented in earlier stages, however, in this model that is not reality.

The Waterfall flow is as follows:

1.Requirements specification

2.Design

3.Construction

4.Integration

5.Testing and debugging

6.Installation

7.Maintenance

Reasons For Criticisms:

The waterfall methodology is viewed by many as a bad system development practice. Their reasoning is due to a belief that all things should be perfected before moving on to the next. Others may disagree that on projects that are vastly complex, there can be no complete perfection and it may have to take place at a later date. For example, a Microsoft Operating System.

This methodology may work for smaller projects that are relatively straight forward, however, there is always the concern that the assigned project will be altered before completion. Other methodologies allow for changes and iterations to be made, making them more suitable to projects that require more flexible requirements.

There can also be no working incremental updates for clients or employers because the system is built by phases. Often making extended funding harder to establish and also makes preliminary funding hard to estimate.

Conclusions:

The waterfall methodology is great for a planning perspective or to give an idea to a committee that authorizes such projects. It is a “basic” outline of how a project should be generally created, however, sometimes iterations and lessons learned later need to be applied at random intervals. During most projects, there is a certain amount of overlap and backtracking due to changes in objectives or in overall design. Certainly the average persons creative mind does not work on a linear or sequential scale and neither does a design team without serious effort. Conclusively, the waterfall method if modified is a solid structure to base a project and needs further improvement to create a successful project or undertaking.

Resources:

http://www.buzzle.com/editorials/3-13-2005-67039.asp

http://www.selectbs.com/glossary/what-is-the-waterfall-model.htm