System Development Life Cycle models

Abstract
The major purpose of the research paper is to describe the phases involved in system development life cycle. It provides a description of the 7-step SDLC model and the 4-step SDLC model. The two models have both comparing and contrasting features as described in the paper. The stages involved in the 4-step model are planning, risk analysis, engineering, and evaluation. For the 7-step model, the phases are planning, system analysis, system design, development, Testing, Implementation, and Maintenance.

Introduction
The success of a project involving system development depends on the careful observance of the stages involved. The approaches may vary depending on the type of the project, but it’s important to adhere to the selected approach. Every project has an initiation stage that defines the commencement of the project, and a final stage that signifies the closure. System development life cycle is a process that has the stages involved in the development of systems. There are several models applicable in system development, and each has a different approach to system development (Lewis, 2008). The principle aim of the research is to describe the 7-step SDLC model, the 4-Step SDLC model, and the associated comparison and differences. It provides the defining characteristics of each model in details.
7-Step SDLC Model
The 7-Step SDLC model is a linear form of approach in system development that has seven stages to follow. The seven phases follow one another in sequence and requires the system developer to adhere to them as outlined. They are planning, system analysis, system design, development, Testing, Implementation, and Maintenance (Buragga & Zaman, 2013).
Phase 1: Planning
It is the first phase and very important in system development. It involves the description of the features and operations required in the proposed system in details. The major focus is on the layouts, process diagrams, rules, and documentation. The project assumes it shape and direction from the planning phase. Planning phase helps to establish whether it is feasible to have a new system in line with the strategic business goals. The main considerations are the resources, costs, time, associated benefits, and other essential requirements (Cervone, 2007).
Phase 2: System Analysis
The project analyst identifies the problem in the organization and responds by providing a solution. The solution has to align with the organizational goals, functions, and operations. The business work to ensure that the needs of the end user are in perspective. The proposed system requirements are considered to ensure that they are attainable. The major activities involved include gathering the requirements, the structural analysis, and the required support. The proposed system must satisfy to meet the needs of the end users before approval for the next phase (Shikha & Jain, 2012).
Phase 3: System Design
The third stage entails the submission of the full details of the specific functions and tools of the proposed system. Other details are the requirements of building the system, features, process diagrams, and the necessary documentation. The end users then discuss and establish their information needs for the system. They also consider the essential components of the system in accomplishing its objectives. The design phase has two major areas; the logical system design, and the physical system design. Logical design is the blueprint of the system, and the physical design has the cost and materials of the system (Valacich, Joey & Hoffer, 2015).
Phase 4: System Development
Development phase converts the idea into paper into the actual system. The organization gets the assistance from professional programmers, database developers, and network engineers to make the solution a reality. They work in collaboration with the company IT experts to develop the system. The stage involves initial development and putting the system into production. Most of the practical work of building and programming the system ends in the development phase. Partial installation occurs as well as training on the key aspects of the system (Lewis, 2008).
Phase 5: Testing
The quality assurance professionals perform integration and testing of the system after installation. Testing has a focus on the programs and procedures involved in the system to ensure that they meet the goals as defined. It may occur severally to check for the errors, bugs, and compatibility until the end user certifies it. Other aims of testing are to ensure ease of use and interoperability. The problems that exist must be addressed through verification and validation procedures (Shikha & Jain, 2012).
Phase 6: Implementation
  Implementation put the project into production. The system is ready for the working environment, and thus extensive training is necessary. The components of the previous systems move to the new system through the preferred method. It can be through phased implementation, pilot testing, parallel conversion, or direct cutover from the old system (Hurst, 2014).
Phase 7: Maintenance
After rolling out the system into operation, some changes, corrections, additions, and modifications are necessary to ensure user comfort. The procedures take place as long as there are changes in the organization. The activities involved in maintenance help to fine-tune and boost the performance of the system and may continue forever (Taya & Gupta, 2011).

4-Step SDLC model
The 4-step model is an iterative software development model mostly applicable in the high-end risky projects. It combines the features of other models, hence is comprehensive than other models. The software development project undergoes through four repetitive stages until the completion of the project. The four major stages involved are planning, risk analysis, engineering, and Evaluation (Schwalbe, 2013).
Planning Phase
Planning is an important phase in system development. It involves the gathering of all the requirements to make the project successful. In the planning phase, the system developer gathers the business requirements for ensuring that they meet the laid out objectives. It acts as the baseline for the system development process. The subsequent steps are the identification of the system requirements, the subsystem requirements, and the unit requirements. The system analyst has to communicate with the business leaders to ensure that what goes to documentation is a replica of the proposed solution.  A feasibility study is also important during planning since it forms the basis of either recanting the process or proceeding with the actual system development. The planning phase lays the foundation for all the subsequent phases (Supannika, Barry & Richard, 2014).
Risk Analysis phase
Risk analysis includes the identification, estimation, and monitoring of the technical feasibility and the management risks in undertaking the project. It is an important stage in system development since it helps to identify the potential threats to successful completion of the system development life cycle. Risk analysis helps to identify the project constraints and hence alternative approaches can be identified to counter the effects of the constraints (Hoffer, George & Valacich, 2006). It also involves addressing of the operational and technical issues associated with the project. As a response to the identified issues, risk mitigation is in focus to address the issues. The evaluation of the risk mitigation strategy determines the future actions.
Engineering phase
The phase involves the development of the planned system.  Testing also occurs in the engineering phase to ascertain the effectiveness of the system in meeting the business goals. The major deliverables obtained from the phase are the program code, test case and results, summary report, and the defect report (Taya & Gupta, 2011).
Evaluation phase
It is the last phase that involves a review of the progress and a consideration of all the parameters. The major problems identified require addressing by taking the corrective measures. The customers also evaluate the system and give their feedback and approval (Shikha & Jain, 2012).
Comparison and Contrast of the 7-Step and the 4-Step model
The two models discussed apply to system development life cycle though they follow differing approaches. In both, there is planning as the initial and most important phase in system development (Hurst, 2014). Both models also consider testing as an essential aspect of system development that comes before implementing the system into action. That notwithstanding, the two SDLC models have varying features that that form the basis of their different approaches.
The 4-step model allows customer feedback and evaluation, thereby allowing modifications and changes in the progress of system development. However, the 7-Step model does not have much customer feedback since their concerns never end up in the system. The 4-step model is more flexible than the 7-step model of the processes involved in system development. Risk analysis is an essential aspect of the 4-step model that lacks in the 7-step model. The 70-step model is appropriate for the small and the less-risky projects, unlike the 4-step model that is good for the large and more risky projects. The 7-step model is linear with clearly defined timelines, unlike the 4-step model that is iterative and may continue infinitely (Hurst, 2014).
Conclusion
System development life cycle is an essential process in project management since it ensures a successful completion of the project. SDLC occurs in different models, but the focus of the paper is on the 7-step and the 4-step models. The 7- step is linear and suitable for the small projects whereas the 4-step model is iterative and suitable for the large projects. In SDLC, the choice of the model depends on the type of the project.

References
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Cervone, H. F. (2007). The system development life cycle: Systems 23(4), 348-352.
Hoffer, J., George, J., & Valacich, J. (2006) Modern systems analysis and design 6th Edition: Prentice Hall: U.S.A.Texts:
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Taya S. & Gupta S. (2011) Comparative Analysis of Software Development Life Cycle Models, IJCST Vol. 2(4)
Valacich J., Joey F. & Hoffer A. (2015) Essentials of Systems Analysis and Design Pearson Education ISBN 1292076615, 9781292076614

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