Software Development Models: Waterfall and Whirlpool

The Waterfall Model is given its name by the way the phases run downwards (like a waterfall). It comprises of five phases and the next phase cannot be started until the last one is totally finished. This means that if a problem arises later on in production from an earlier phase, it cannot be corrected without it affecting the rest of the production. The first phase of this model is Requirements. This is like the brief at the beginning of the project, it tells the designer what to do. Phase two is Design. The third phase is Implementation. This is basically the phase of construction or coding. Phase four is Verification – testing to make sure it works. The final phase is Maintenance which is simply the upkeep of the software. See the image of this model below.



The Whirlpool Model combines the Waterfall Model with the Prototyping Model. However, this model only has four phases. During the first phase, system requirements are given and risk assessments are carried out. The second phase is probably the most import is this model. Here, all possible alternative strategies are analyzed. If the risk assessment from the phase before flag up any uncertainties then this phase is used for preliminary prototyping with the data already collected to find out a possible solution to the problem. The third phase a prototype of the software which has some of the characteristics of the final design, like a scaled down model. The final phase is a second prototype being made by analysing the first one in terms of strengths and weaknesses. The second prototype is then tested, and the final phase is repeated. The best thing about this model is that it allows the designer to deal with more than one phase at once unlike the Waterfall Model. At the end of each phase, a review is completed. See the image of this model below.



The Use of the Whirlpool Model in Web Design
The Whirlpool Model is a far better model to use than the Waterfall Model when making website for a number of reasons. The first one being, that the internet is changing all the time by means of new coding and applications. So by using this method, the developer can keep going back to the website and changing it to keep it up to date.

Another reason is that each phase doesn’t have to be completed before moving onto the next one. This would be fairly hard to do as the developer is constantly changing the code when making the website when something goes wrong.

A third reason of choosing the Whirlpool Method over the Waterfall would be that in this method, testing is done constantly, and this is needed for web design.