System Development Life Cycle Models

By Author: Sherry Roberts
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Introduction
System Development Life Cycle is a framework that describes the activities carried out at each stage of a software development project. It is the structure imposed on the development of a software product and has several models used that describe the approach to each activity taking place. The designing of the SDLC process was to ensure that end result solutions that meet the requirements of the user in support of the business strategic goals and objectives. The process also provides a comprehensive guide to assist the project managers in all the aspects IT system development. There are different methods in SDLC that are in use, and each of them has a basis on the 7-step model (Shikha & Jain, 2012). The model has a procedure on system progression required to change an IT system from conception to disposition. The seven steps are conceptual planning, requirements definition, design, development and testing, implementation, operations and maintenance, and deposition. Conceptual planning involves the identification of a need to have or enhance a system. The developer assesses the costs and feasibility, risks, ...
... and the various project planning approaches available. The next phase of planning and defining the requirements comes after defining the project and committing certain resources for the project implementation. In the design, decisions are made on how to meet the functional requirements of the system. There is both a preliminary and a final system design in order to fully develop the system. The next step involves developing and testing whereby systems are acquired based on the detailed specifications of the design. The system should function as expected and according to the requirements provided. Installation entails the incorporation of the system into the production environment. It also involves the training of the users, data conversions, and evaluation of the operations of the business. In the operations and maintenance, the main objective is to ensure that the system meets the needs of the sponsor, as well as all the specifications. In the last phase of disposition, the system is ready for shutdown after it meets the desired end result (Sadagopan, 1997).

Common characteristics
In the two methods, the system developers have to identify the system requirements before working on the development process. However, the seven-step model is tedious in this and takes more time than the six-step model (Taya & Gupta, 2011).
In both methods, the developers have to test the system before it is fully allowed to operate although the testing occurs at different times.
Different characteristics
It is a prototyping model that uses an iterative approach other than the linear approach used in the seven-step model. It carries out the implementation and maintenance phases after testing the prototype and finding it to meet the requirements of the user. In contrast to the seven-step model, testing occurs before implementing such that in case of any issue, it is not easy to identify. The 6-step models takes less time to analyze, design and implement a system, other than the seven-step model. Thus, it avoids delays that could arise in the system development life cycle. The prototype helps in having smaller versions of the system being developed, hence offering a quick and less costly approach to system development (Taya & Gupta, 2011).
The 6-step model allows for users suggestions on ways of improving the prototype. The suggestions are incorporated into another prototype and the process continues until a final system is developed. Therefore, the knowledge and challenges faced in developing the prototype are used to develop the real system. In comparison with the seven-step model, it has no smaller sections of the system under development, and hence the process of developing the system continues entirely. In addition, it is easy to detect and correct any errors in the prototypes, other than working on the entire system such that a slight error may lead to starting the whole process afresh. The method is highly flexible in comparison to the basic seven-step model that is rigid in its operations. It has a higher guarantee of success than the original seven-step model (Hurst, 2014).

The model provides faster results, requires less up-front information, and has greater flexibility. It divides the project into small steps that allow the development team to demonstrate results early and hence obtain feedback from the users (Shikha & Jain, 2012).
The required specifications are identified at the beginning of the system development life cycle and remain the same throughout the process. It is similar to the seven-step model that also identifies the required specifications at the beginning of the process. In addition, the two system development life cycles are less costly to develop and use. The systems used in the 5-step model are simple that is similar to the seven-step model. Hence, both are easy to understand and follow at each stage of the process. The phases in the 5-step model do not overlap just like in the seven-step model (Taya & Gupta, 2011).
Different characteristics
The requirements are not well understood in the beginning until the process reaches a considerable stage, but in the seven-step model, the requirements are well understood in the beginning. In this, model, there is a possibility of having a reusable component within the system, but it is not the case for the seven-step model. Risk analysis does not arise in the model, but it is a key considerate in the seven-step model. The model has a high possibility of success, unlike the other model. It takes lesser time to the implementation than the extended duration for the seven-step model. The model is less flexible in terms of uses, unlike the other basic model that is rigid according to the specifications outlined (Taya & Gupta, 2011).
Spiral model

Common characteristics
It combines both the concepts of top-down and bottom down approaches. It can also be applicable to other models, hence referred to as a meta-model (Boehm, 1988). The specifications of the requirements for the entire process are identified at the beginning as it is the case for the seven-step model. The requirements are easy to understand just like those of the seven-step model.
Different characteristics
The cost of developing the system is higher using the model than that of the seven-step model. In addition, the system developed using the approach is more complex than the seven-step model. It involves the carrying out of the risk analysis throughout the process unlike that of the seven-step model that does it only at the beginning. It requires the involvement of the user at all phases, unlike that of the seven-step model in which user involvement is at the beginning. The model has a high guarantee of success and is more flexible, unlike the other model which is rigid and has a limited guarantee of success (Shikha & Jain, 2012).
Conclusion
All the models developed for the system development life cycle have a basis on the basic seven-step model. However, each of the developed models has varying and distinct characteristics that identify them from others. The comparison presented in the paper focuses on the iterative, prototype, and the spiral models that are different in various aspects to the seven-step model. Therefore, every system developer has to understand each of the models and their features in order to use a model that meets the needs of the project at hand. However, all of them have a basic structure that identifies them as SDLC types.

References
Boehm, B. W. (1988). A Spiral Model of Software Development and Enhancement: Computer, 61-72
Hurst J. (2014) Comparing Software Development Life Cycles; SANNS Software Security
Sadagopan S. (1997) Management Information Systems; pp. 174-184 ISBN 8120311809, 9788120311800
Shikha M. & Jain D. (2012) A comparative analysis of different types of models in Software development life cycles International Journal of Advanced Research in Computer science and software Engineering; Vol. 2(5)

Sherry Roberts is the author of this paper. A senior editor at Melda Research in best research paper writing service. If you need a similar paper you can place your order for a custom research paper from affordable custom research papers services.