System Development Life Cycle

Introduction

The multistep process of developing and implementing an information system is referred to as the System Development Life Cycle. There are various SDLC models with each consisting of a series of defined phases or steps. This paper discusses two types of System Life Cycle Models: Seven steps model and the spiral model.

Seven step model

Planning

The objectives and requirements of the project are determined at the planning step. An estimation of resources including costs and personnel is also made in relation to the proposed project. The available information is analyzed, and alternative solutions are considered. When the most viable alternative is arrived at, the information is put together into a project plan. (Jeremy, 2008)

System Analysis

The end user requirements are determined at this phase. The project team determines the end-user requirements with the assistance of customer focus groups, which present their needs and expectations on the system and how it will perform. The needs and requirements are documented in this phase. (Jeremy, 2008)

System design

The design step is the architectural phase of system development. Charts are used to show the flow of data processing, and the project team establishes the most logical design. The operations and functions of the system under development are described in detail during this phase. Reviews on the design are also conducted to ensure the design addresses efficiency, practicality, cost, security, and flexibility. (Jeremy, 2008)

System development

During the system development phase, the system developers execute the requirements of the design step. Actual user interface screens and database are designed by the developers, the code for the data flow process are also generated in this phase. The system development phase entails the conversion of the detailed design into a finished product. (Jeremy, 2008)

Testing phase

The testing phase involves the testing of all aspects of the system for performance and functionality. The whole system is tested for integration with other products and other previous versions with which it requires interacting. Fundamentally, the main purpose of the testing step is to validate that the system includes all the end user requirements reflected in the analysis step. Additionally, the testing phase also ensures that all the functions are accurately functioning; that the system is aligned to the standards of the business and the end users and that the system works with all other systems including the previous systems. (Jeremy, 2008)

Implementation Phase

The implementation phase entails the deployment and installation of the system in end user’s premises, ready to become running. End user training may be required to ensure that they can effectively use the system. The length of implementation is dependent on the complexity of the system.

Maintenance Phase

The maintenance phase is carried out on a periodic basis to ensure that the system does not become obsolete. Maintenance involves continuous evaluation of system’s performance. It also entails providing latest updates for particular system components to ensure that it meets the right standards. (Jeremy, 2008)

Spiral model

The Spiral Lifecycle model is comparable to the Incremental model except that it incorporates a risk analysis process. A project passes through four phases repeatedly in sequence in spirals. Critical requirements are identified for the first spiral at the start of the process while the Subsequent spirals add functionality to the baseline spiral. (University of Maryland, 2007)

Planning Phase

The business clearly defines its high-level requirements and project goals during this phase. The need and purpose of the system are also established and documented during this step. Key rules are also identified here in the initiation phase. The planning phase entails defining timelines, resources and other project related information. Interviews are conducted to help in developing a comprehensive system that fits users’ requirements. (University of Maryland, 2007)

Risk Analysis

The risk analysis step is fundamental to assess both management and technical risks associated with the project. Risks are identified, and alternative solutions are developed to address factors that may deter the successful completion of the system. (Shelly & Harry, 2009)

Engineering step

A representation of the system is built at this phase. A prototype is tested against the risk evaluated based on the expectations of the end users. The prototype is refined and rectified until end user expectations are achieved.

Evaluation

The final system is thoroughly evaluated during this step. End user feedback is required on which to base the evaluation.

The figure shows spiral model representing four phases; planning, risk analysis, engineering, and evaluation. The radius component represents the project cost while the angular component represents the progress in the current spiral.

Comparing the two models

Spiral Life Cycle Model represents a very flexible system lifecycle model. The seven step model is a rigid life cycle model system on the other hand. The project manager in a spiral model can determine the development phases according to the complexity of the project. The spiral model is transparent as Project monitoring is very effective and easy given that each phase and each loop is reviewed by concerned people. The seven step model does not allow much interaction with the end users during its development. This makes it less transparent. Gary (Shelly & Harry, 2009)

The spiral model is more attractive compared to the seven step model as Risk Management is an inbuilt feature of the model. In a spiral model, alterations can easily be introduced later in the life cycle. Coping with such changes isn’t a difficult task for a spiral model project manager. The introduction of changes in the seven step model presents a difficulty.

Spiral models are appropriate for high-risk projects, where business requirements may be unstable. They are not suitable for low-risk projects. Seven step models suit low-risk projects where projects are not exposed to high risks to warrant detailed risk analysis.

Spiral Model usually involves high cost compared to the seven step model. Seven step models are cheaper since risk analysis is not fundamental to the development process. They do not also require expertise to carry out these steps. (Valacich et al, 2015)

Protocols and Rules need to be followed properly to successfully implement the spiral model. The factor makes it tough as they should be followed throughout the span of the project. Seven step model is easy to develop rules, and protocols are not detailed or complex. In the spiral model, using the same prototype in future presents a difficulty as a result of various customizations allowed from the client.

References

Gary Shelly, Harry J. Rosenblatt (2009) Systems Analysis and Design Cengage Learning ISBN0324597665, 9780324597660

Jeremy Lewis (2008) SDLC 100 Success Secrets Emereo Pty Limited ISBN 1921523158, 9781921523151

Valacich J., Joey F., Hoffer A. (2015) Essentials of Systems Analysis and Design Pearson Education ISBN 1292076615, 9781292076614

University of Maryland (2007) Conceptual Model for the Systems Development Life Cycle ProQuest ISBN 0549425217, 9780549425212

Weitzel, J. R., & Kerschberg, L. (1989). Systems: THE SDLC. Communications Of The ACM, 32(4), 482-488

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