Question

Compare the elements of the basic Software Development Life Cycle with 2 other models. A paragraph for each of 3 models describing each. Then write a paragraph comparing the differences and similarities among the 3.

Answer 1

Let me explain the elements of a software development life cycle.

• Planning :   In this phase, the software engineers will gather the required data from the clients. The client will give the appropriated information to the software engineers. Hence, the software engineers will develop a software specification document wherein the specification details of the software is recorded. This is to implemented in the next steps.
• Design : This phase is concerned with the overall design functionality of the software. Here, an overall design architecture of the software is created. For example, an overall picture of the software in terms of Data Flow Diagram (DFD), Unified Modelling Language (UML) is created.
• Implementation : The designed architecture in the previous step is implemented by software coders using an appropriate programming language in this step.
• Testing : The implemented program is tested for all the possible use and test cases. There will be an independent testing group who will test the programs in this step. For example, checking all the if conditions are working properly and the program is well running for the boundary values and all.
• Deploying : Now, the fully checked and tested software is deployed in a real time environment.
• Maintainance : This step is concerned with the maintainance task of the software. Fixing the errors occuring in real time, task of updating cetain functionalities, fixing errors such tasks are done in this step.

Following is the explanation of 3 life cycle models and its functioning:

• WATERFALL MODEL

   In case of waterfall model, the elements of SDLC is performed in a sequential manner.

   Initially, requirement phase will collect all the required informations about the software. Then, the system design of the software will be created. Then, the system will be implemented using a programming language. Then, sequentially the testing of the system takes place using appropriate tools and then, the deployment of the system in real world followed by the maintainance of the system. This entire model follows a sequential flow. It is also known as the classical model. This is the simplest model

• ITERATIVE MODEL

   This is an advanced version of the waterfall model. Unlike, the sequential modelling of each step. Here, the overall design of SDLC is iteratively improved. The steps from planning or requirement analysis is evaluated till the verification or evaluation of the system is done iteratively. In each iteration, the overall performance of the system is evaluated. Once, it reaches a satisfactory stage, then sofware is deployed.

• SPIRAL MODEL

    This SDLC emphasizes on risk management. It performs a risk driven approach for developing the software in an iterative manner. In each iteration of this model, it will check the risks associated and then resolve it and proceed further. That is requirement analysis and design, check the risks and resolve. Again reqirement analysis and design and check the risks until it is satisfied. Then, develop the next version of the product. Spiral model is a combination of waterfall and iterative model. Unlike iterative method, in spiral model the risk is the key and it is analysed during validating the project.

DIFFERENCE BETWEEN THREE MODELS:

• Unlike, iterative and spiral model, the waterfall model is sequential in nature. It is also the most outdated development cycle. It is used for small and simple projects.
• Unlike, waterfall and iterative model, the costs associated with spiral model projects are so high. It is suited for complex projects.
• Waterfall model requires entire description of the specifications at the very beginning of the project. Otherwise, it will fail. But, in iterative and spiral model, the requirement specifications keeps on changing as the project develops.
• The flexibility of waterfall model is the least. Then comes iterative model followed by the spiral model.
• The most maintainable projects are developed by the spiral model. Then, comes the iterative model and waterfall models are the difficult to mainatain.

SIMILARITIES AMONG THREE MODELS:

• In each of the three models all the elements of design are followed. However, in a different manner the overall aim is the development of a software.
• Similarity between spiral and iterative model is that both are iterative and accomodate changes during development process.