Waterfall and Whirlpool Software Models

1. Describe, compare and contrast the "waterfall" and "whirlpool" software development models

The waterfall model as described by Tecademy (Unknown date) is where
"all stages were defined by a set of deliverables, each one of which would be agreed and signed off before proceeding to the next stage."
In other words, each step of the cycle would be done one at a time, signed off and moved to the next step. Once this process was completed, the project would be finished. See diagram below.

Figure 1 - Waterfall Model
http://upload.wikimedia.org/wikipedia/en/e/e2/Waterfall_model.svg

On completion of the development model, the project would come to an end. Each step would be looked at and worked on until everything was finished and acurate, in essence "freezing" the development of each stage. The whirlpool model, on the other hand is similar but more diverse.

The whirlpool model is designed with the intention that the cycle will never end. Once the project has begun, the user proceeds through each task to the best of their ability, once the cycle has been through once, it begins again to constantly keep the development of the system up to date and accurate to advances in technology and society. The image belows is an example of the cycle.

Figure 2 - Whirlpool Model
http://www.jiscinfonet.ac.uk/InfoKits/implementing-elearning/sfc-toolkit-lifecycle

As you can see, projects developed under the Whirlpool model are intended to be a continuously developed and enhanced as the cycle will never end.

Let's compare the two. The waterfall model would be great to use for short, quick-fire projects that need to be completed and tested under a short period of time. This is because each stage of the model is done step by step, completed and signed off. As there's no plan to return back to the beginning of the project, if this model is used for on-going systems or a system that will take a long time, the data could become out of date or irrelevant.

The whirlpool model is used for projects that are either longer in length or will require extensive updating due to its nature of being cyclic. Starting with the Analysis, the development of the system if first looked at and then the cycle is stepped through one at a time. Once the cycle returns to the start, it is expect to go around again. By doing so, this ensures all data, technologies and information is relevent, current and accessible across multiple platforms.


2. Describe how the "whirlpool" software development model can be applied to WEB page design.

Bearing the previous question in mind, the whirlpool software model is a great development tool to use as websites are generally constantly required to be up to date and accessible on many platforms. Using the whirlpool development model, you can proceed through the cycle, analysing the current state of the solution to solve, plan out a design for the website to meet the requirements, deploy the website and then review the website making sure it works and functions as neccessary. If not, the cycle can be repeated to make sure all these aspects are adhered to. This cycle will be continuous and enables the site to be maintained and fully updated reguarly.

References

TECADEMY, Unknown. [online]. Waterfall vs. Whirlpool. Available from: http://www.puffinonline.com/Tecademy/003%20Waterfall%20vs%20Whirlpool.pdf Accessed: 11th December 2009.