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The Systems Development Life Cycle

 Many steps must be followed when developing a new information system. The system development life cycle (SDLC) is a model that tries to structure these steps. SDLC can be defined as a step-by-step approach that is used in developing information systems. At the early stages of development, three choices need to be made. The first one is the task that will be handled by your information technology human resource. This is known as in-sourcing. Self-sourcing is the next step that focus on how much end-users can do. The last choice is known as outsourcing that measure how much the third-party outside can do outside the organization (Beynon, 2009).  

There are seven phases in an SDLC model:
Phase 1: Planning:
This phase focuses on the solid plan that will work as a guide for developing your information system. It involves the project manager who is trained to plan and manage projects. The manager defines the project plan and develops it. He follows the plan to ensure that it is completed in time. There are three activities in this phase that include defining the system, setting the scope of the project, and defining the project plan.
Phase 2: Analysis:
In this phase, the IT experts do research on the business requirements for the system proposed. A joint application development session is also developed in this phase. The business requirements are then approved after which errors are identified to be fixed in the process.

Phase 3: Design:
In the third phase, a technical blueprint is designed to show how the proposal system will progress. The design phase focuses more on technical work more than business work. The software and hardware are well defined also for the telecommunication equipment that are needed to run the system. A graphic presentation of the design is finally made.
Phase 4: Development:
All detailed design documents are important in the development phase. They are used in building a technical architecture. In this stage, a database for the software programs is made. Due to the changing technology, developing a system may take a long time.

Phase 5: Testing:
In the testing stage of SDLC, the system is tested to ensure that it is working, and it meets all the requirements. Test conditions are used depending on the expected results. All tests must be done without skipping any of the steps.

Phase 6: Implementation:
In this stage, the system is distributed to all the human resource departments to be used for daily activities. The workers will use a user document provided to will give guidelines on how to use the system. Internal training to the knowledge workers is also important.

Phase 7: Maintenance:
The final stage is the maintenance stage where the SDLC is monitored and supported to ensure that the goals of the business are well met. I help desk can be used for workers to enquire about the new system. Business is by nature dynamic and not static, and as business change, the system will also need to change. This means that you need to keep your system updated depending on the changes in the business. Workers are also informed of any changes that take place in the new system to ensure that the goals are met (Whitten, 2003).

SPIRAL SDLC MODEL
The spiral model is as prototype and sequential model that is mainly used for large projects that require progressive enhancement. In every spiral, there is a specific activity done to give the output that is part of the management software. These activities repeat themselves in the whole cycle until the complete software is complete.
There are four phases common in spiral software that includes planning, risk assessment, engineering phase, and evaluation.
Planning:
In planning, the business requirement is gathered, and a feasibility study done. Then the requirements highlighted are streamlined, studied well to produce a final list of requirements.

Risk analysis:
In the risk analysis stage, various activities are done to help in identifying potential risks in the project. This involves studying the requirements critically and documenting all potential risks and the measures that can be taken against them (Fabrycky, 2006).
Engineering stage:
In the engineering stage, the actual development takes place where technical work is done. The project focuses on engineering process more than the business requirement. The software is then tested, and the results recorded. They are summarized, and a defect report prepared.
Evaluation stage:
In this stage, the customers are allowed to do an evaluation of the system and give their comments and views about its functions and efficiency. A document is prepared for the approved feature of the system.

The above picture is a presentation of a spiral model where each color shows a different spiral. In the first phase, all the four activities are done. The process repeats itself in the other three spirals.
COMPARISON
The spiral model is mostly used where the project is very large and where the risks need a continuous evaluation. It can handle complicated requirements, unlike the 7 stage model that is only appropriate for normal-size projects. The fist model is only applicable when a new system is needed in a business organization, unlike the spiral model that does well when a system requires several changes. The 7-phase model takes a short time while the spiral model needs more time, to get the feedback of the user and the customers. Frequent releases also do well with the spiral model than in the 7-stage model. Also, the spiral model has more advantages than the 7-stage SDLC. The spiral model develops faster than the 7 stage model. It can handle large systems in a more strategic way than the 7 stage model. The process of risk evaluation is credible, and all phases are always under control. Unlike the first model, the spiral model allows more features into the system, which are added systematically, and the software always release early to the users. The customers in the spiral model are allowed to assess the system and give their comments and views about the system. This is followed by a comprehensive report that includes the approved features and the implemented changes. In the spiral model, the changes made are easily implemented, and, therefore, less time is used to review it.
The 7 stage SDLC model uses experts in the risk assessment stage, unlike the spiral model that do not consider its importance. The spiral model does not benefit small project, but the 7-stage model do well. The spiral model can infinitely go, and there is much documentation involved. The intermediate phases are also more compared to the 7-stage model. When the spiral model is used for small projects, it tends to be too expensive to implement. In the first model, every stage has its independent activities. This allows the management to move to the next stage to perform a different task. The circle is complete at the seventh stage. In the spiral, every stage has its cycle (Cummings, 2006). The four activities are repeated in all phases. This makes it have four complete loops and hence 4 phases. The experienced human resource is needed in the implementation of this SDLC model. The model is costly since risk assessment and analysis is more involving. In 7 stage model, the company uses its existing experts in risk analysis. The users are trained on how to use the system, and an inquiry desk is made available for the workers to consult (McConnell, 2000). The spiral model does not have the training section. This makes it hard for the users to operate a new system.
CONCLUSION
In a nutshell, the two models have both similarities and differences. The major difference is that the first model has seven stages while the spiral model has only four stages. Their methods of risk assessment are different and hence making 7 stage model reliable only for small projects. Big projects can successfully be carried out using the spiral method since it has more integrated risk assessment and analysis process. Although the progress of a spiral model is fast, it takes more time since all the affected parties are involved in the implementation process. More time is needed to allow the users to evaluate the system before the final approval.

References
Beynon P. (2009). Business Information Systems. Palgrave, Basingstoke.

Fabrycky, W. J. (2006) Systems engineering and analysis (4th ed.) New Jersey: Prentice Hall.

Cummings, H. (2006). Management Information Systems for the Information Age. Toronto, McGraw-Hill Ryerson.

McConnell, S. (2000) “7: Lifecycle Planning”. Rapid Development. Redmond, Washington: Microsoft Press. p. 140.

Richard H. (1986). Tutorial: software engineering project management. Computer Society Press of the IEEE. p.130.

Whitten, J., L. (2003). Systems Analysis and Design Methods. 6th edition.

Carolyn Morgan is the author of this paper. A senior editor at MeldaResearch.Com in college research paper services. If you need a similar paper you can place your order from best medical essay service.

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