Quiz 2: Software Life-Cycle Models

Winburg mini case study using waterfall model: No the waterfall model is not effective than the evolution-tree model. Waterfall model: In Waterfall development model, the entire process is sequentially flows downwards through all the processes of software development lifecycle. Evolution-tree development model: In evolution-tree development model, the entire process is developed iteratively like and follows incremental model. This development model gives importance to maintenance. From the above figure, • The phases in the software development lifecycle are followed correctly and feedback loops in the development process are utilized. • But, the figure does not show the sequence of iterative events like evolution-tree development model. Conclusion: Therefore, the waterfall development model does not give exact picture of things happening in the software development lifecycle. Hence, evolution-tree development model is effective than waterfall development model.

The Winburg Case study in Section 2.2 is explained using evolution tree life cycle. The Episode 2 of Section 2.2 of Winburg Case Study explains that:- To get the 98 percent accuracy double precision numbers for all mathematical calculations should be used. But because of use of double precision numbers, program becomes slow and results in long response time. The required 98 percent accuracy can be attained if single precision numbers are used. If it is assumed that the single precision numbers are used from the starting then the Episode 2 of Section 2.2 of Winburg Case Study will be removed. The resulting evolution tree life cycle is as follows: • Episode1 - The first version of the software is implemented. • Episode2 - It was found that average response time was 4.5 seconds which is far more than required 1 second. So, a faster algorithm was used and redesigning and reimplementation is done. • Episode3 - It is found that project is behind schedule, over budget and the Mayor asks for increase in the accuracy. To fulfil all this, new requirements, new designs are adopted to achieve the accuracy.

The Millers law explains that any human being can only process seven information or chunks approximately at one time. But any software project will have more than seven components such as seven or more requirements or variables. The solution for the above is done with stepwise refinement, which focuses on important aspects to be processed first and less important aspects to be done later. As stated by Miller's law the stepwise refinement is done accordingly which explains that concentrate on seven most important aspects and after they are completed work on next seven important aspects and so on. So, it is an incremental process.