Compare and contrast Systems Development Life Cycle (SDLC Models).

(a) Describe the 7 Steps SDLC

(b) Describe a different SDLC Model (4 steps or 12 steps)

(c) Compare and contrast the 7 Step Model and the second model you selected (4 steps or 12 steps)

This paper will provide a description of seven steps Systems Development Life Cycle Model which is the Prototype model and also the paper will provide a description of SDLC Model known as spiral Model which has four steps of development. Finally, the paper will provide a comparison and contrast of the both the prototype seven model and Spiral four type SDLC model.

(a) Prototype seven step model

This type of model incorporates the idea that instead of freezing the requirements before the designing and coding of the system, a sample look alike system known as prototype is built in order to comprehend the system requirements (Isaias & Issa, 2015). However, the prototype is mostly built based on the currently know requirements. The main significant of having the prototype is that the customer is able to have a hands-on experience with the system just as an actual feel which aid in giving the customers confidence on how the system will look like and in case he or she need some adjustments in the system configuration then with the prototype, such proposals can be made which will be incorporated into the final system (Plyler & Kim, 2009).

This type of models is very attractive especially when ultimate system is very complicated or very large in size. However, in most cases, prototypes are not complete systems since many of the details are not yet built in the prototypes but the core goal is to provide a system with overall and detailed f functionality. Prototype model is also know to be the seven type models due to the seven phases that are involved in the development of the system and these seven stages or phases include; Requirement gathering where the developers interrogate the customer on what exactly needs and the details that should be incorporated in the system. The second stage is the Quick design which is a rough copy of the prototype system, the third phase is prototype building where a sample system that looks similar featuring the customer requirements is build (Jovanovich & Dogsa, 2003). The fourth stage is customer evaluation and it is at this stage where the customer is able to use the prototype and confirm if the original system of the prototype will satisfy his or her needs, and the customer can propose for adjustment at this phase. The fifth stage is prototype refining and it entails making adjustments that have been proposed by the customer to the prototype to ensure that all the needs are addressed. The sixth face is the Product engineering where the prototype is configured to original system and finally the seventh phase is the testing where the already engineered prototype is tested to ensure that all the requirements are meet and it can serve its purposes as demanded by the customer (Plyler & Kim, 2009).

For instance, prototype model is mostly used when the system that is desired to be developed needs to have more interaction with the customer. Some examples of prototype models include online systems and web interfaces which contain high levels of interaction with the customers. Therefore, prototyping ensures that the customer work constantly with the system as well as he or she provides viable feedback that is incorporated in the prototype to come up with a reliable system and therefore, such models are mostly recommended for the development of human computer interface systems that needs more user interaction.

(b) Spiral four step model

Spiral model is a four phase model that is developed through the combination of sequential as well as prototype model and it is mostly recommended for the development of large projects that entails consistent enhancements. For instance, there are specific activities that are carried out in single iteration or rather spiral where the output is known to be a small prototype of the main software and therefore, the same activities are carried out repeatedly for all the spirals to appoint where the whole software is build.

The four phases within this model include Planning which entails studying of requirements and gathering as well as reviews to ensure that the requirements are streamlined. The second phase is Risk Analysis and entails studying of the requirements as well as brainstorming to identify any potential system risks. It is at this stage that the risks identified are studied and counter strategies are planed early enough in order to facilitate efficiency (Mishra & Dubey, 2013). The third phase is engineering and this is where the actual development as well as testing o the software is carried out in order to establish if the requirements are met and some issues are determined at this stage like code testing and retrieval of test result, test summary report as well as defect report. The final phase in this model is the evaluation of the system and it entails having customers to have hands-on evaluation of the software and at this stage they provide feedback that and approval of the software.

(c) Comparison between prototype seven step and Spiral four step models

In prototype seven step models, the methodology may increase the general complexity of the system as the target of the system may expand beyond original plans (Mishra & Dubey, 2013). This is due to the fact that carrying out all the seven phases might lead to repetition of tasks and inclusion of other details that will make the project more expensive. On the other hand, the spiral four step models entails fast development of the system since only four phases are undertake to ensure that the system is functional. This model facilitates time management and a lot of capital is saved since it takes little time.

In prototype seven model, the incomplete application at times causes the application not to be put into use the same way the full system was designed, meaning that at some point, the model main entail incomplete or inadequate problem analysis that might affect the functionality of the system (Plyler & Kim, 2009).. On the other hand, spiral four step model allows development of lager and complicated models that are created on timely basis and handled in a strategic manner that helps to eliminate the essence of inadequate problem analysis. Besides, the engineers in spiral four step model, they have full control over all the phases of development hence minimizing the occurrence of errors.

Contrast between prototype seven step and Spiral four step models

In prototype model, errors can be detected much earlier to facilitate mitigation which also applies to spiral model since the evaluation of risk is done properly hence ensuring that there are no system errors (Mishra & Dubey, 2013). On the other hand, complex function in prototype models can be identified and quick implementation carried out which applies to the Spiral model whereby the model has also room for customer feedback as well the changes that the customers might propose. Meaning that despite the fact that the in prototyping model the users have prior hands-on experience of the system, in spiral model, the customers are allowed to provide their view of the suitability of the system and also they are allowed to view each development process to ensure that their requirements are exhaustively incorporated into the system.