SDLC Models
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SDLC models
The seven stage SDLC model
There are several models of designing systems. In this section, the paper will be on the seven steps of system development life cycle. The seven steps include planning, development, implementation, Testing, system analysis, system design, and documentation (Garraffa, 2016). Every step is important in the end product of the scheme.

Concept Planning

This stage is the initial step of any life cycle of a system. It is amid this step that needs to obtain or essentially improve a system is distinguished, the economic worth and expenses are evaluated, and the dangers and different methodologies of planning a system are characterized. The roles and obligations regarding the Asset Manager, Sponsor's Representative, System Development Agent (SDA), System development Agent (SSA), and different part is in SDLC approach are assigned amid this stage and redesigned all through the framework's life cycle.

Arranging and Requirements Definition

This phase starts after the project has been characterized and required assets have been submitted. The principal part of this stage includes gathering, describing and approving functional, support and preparing necessities. The second part is coming up with the initial life cycle administration plans, including planning the project, configuration administration, Configuration Management (CM), support, operations, and preparing management.

Design

Amid this stage, useful, support and preparing necessities are converted into preparatory and detailed outlines. Choices are made to address how the system will cater for functional needs. A preliminary framework design, accentuating mechanical components of the design, is created as an abnormal state control. At that point, a last (definite) structure outline is delivered that grows the plan by determining all the specific detail expected to build up the system.
Development and Testing

During this stage, systems are produced or procured according to a detailed outline of the design. The system is approved through a succession of the unit, mix, execution, system, and acknowledgment testing. The goal is to guarantee that the capacity of the system is as expected and that support's prerequisites are fulfilled. All the components of the system, interaction, applications, and related documentation are acquired, tried, and coordinated. This stage requires the strong participation of the user to confirm thorough testing of all prerequisites and to meet all business needs.

Implementation

During this stage, the new or improved system is introduced in the working environment, users are educated, information is changed over according to the requirements, the system is swung over to the sponsor, and business procedures are assessed. This stage incorporates endeavors required to execute, resolve system issues recognized amid the usage process, and plan for sustainment.

Operations and Maintenance

The system gets to be operational amid this stage. The stress amid this juncture is to guarantee that sponsor needs to keep on being met and that the system keeps on performing as per expectations. The software and the hardware parts of the system are regularly upgraded to ensure that the system is operational. The training of the users is continuous at this stage, as required, to familiarize new users with the system or to acquaint new elements with current users. Extra user support is given, as a progressing movement, to resolve reported issues

Disposition

This stage is the end of the system's life cycle. It accommodates the precise end of a framework to guarantee that vital data is saved for potential future access and additionally reactivation. When the system has in in disposition stage, it means it is surplus and additionally outdated and has been booked for a shutdown. The accentuation of this phase is to guarantee that the system is bundled and discarded as per appropriate directions and prerequisites.

The four-step model

According to Wixom Dennis and Tegarden, the system development life cycle is the process of realizing how the information system can be useful to the day to day activities of the business (Dennis, 2015). The process is done by designing a system, building and delivering it to the users. The three men suggested the four-step model which includes; planning, analysis, design, and implementation.

Planning

In this stage of planning, two activities take place. The first one is the feasibility study. Feasibility study involves the analysis of the economic aspects of the system that is analyzing whether the organization can afford and whether it will benefit the company. The other item in feasibility is organizational and operational aspects. Here the team considers if it needs the system and whether they will use it. The last category in the feasibility is the technical part of it. The company considers if they are in a position to build the system and the availability of the technology to support it. The second item in planning is creating a plan (Highsmith, 2013). Creating a plan involves having a general view of the system and it is important because it keeps the project on track, and also it can be used for evaluation.

Analysis

In the analysis step, the plan is now broken down into parts and also involves the drawing of a diagram to represent an overview. The concerned parties gather all the required materials by contacting the stakeholders and the technical providers. The analysis also involves developing a proposal that will be presented to the stakeholders.

Design

The designers are responsible for making critical decisions based on what happened in the previous stage. For example, they decide whether the system will be built in-house or outsourced depending on the availability of the materials. It is also upon the designers to decide how the system will operate and how the final users will use it. Finally, in the design step, the feasibility study is reexamined so as to ensure that the company is in a position to support the system.

Implementation

Implementation is the final stage if this model. In this stage, the system is built or purchased and tested. The end users are trained on the use of the scheme to ensure the effectiveness of the program. After the members are trained, a support plan is put in place to facilitate any issues that may arise. The end users are then allowed to use the system and its effectiveness in executing the organization practices is evaluated.

Similitudes and Differences between Seven-Step and Four-Step SDLC Models

As much as the two models are diverse in the quantity of steps they utilize in the system advancement, they are both system improvement models. It implies that the two systems are utilized as a part of the development of software, applications, and systems. The utilization of one model over alternate relies on upon the sort of system, application, or software being created. The four-stage SDLC model is utilized as a part of the development of costly and complicated systems and which require quite a while to be created. Then again, 6 Systems Development Life Cycle the seven-stage SDLC model is utilized as a part of the advancement of straightforward systems, applications, programming (Coronel, 2016).

The two models being SDLC models are distinctive in the number of the stages they utilize during the time spent for the creation of the system. The seven-stage SDLC model, as the name recommends uses seven stages from conceptual planning through to disposition as has been talked about beforehand. Then again, the four-stage model utilizes four steps to guarantee the improvement of the system from the gathering and identifying the requirements and recognizable proof of the system prerequisites for system assessment. The four-stage SDLC display has much documentation in light of its transitional steps which ought to be recorded quickly.

In this way, the progression turns out to be expensive, and it can't be applied to the improvement of small projects (Buede, 2016). Then again, seven-stage SDLC show has less documentation since it doesn't have a middle of the road stages. In this way, the model is not exorbitant, particularly when it is utilized in the improvement of small systems and activities.

References
Buede, D. M. (2016). The engineering design of systems: models and methods. John Wiley & Sons.
Coronel, C. &. (2016). atabase systems: design, implementation, & management. Cengage Learning.
Dennis, A. W. (2015). Systems analysis and design: An object-oriented approach with UML. John Wiley & Sons.
Garraffa, M. S. (2016). The one-dimensional cutting stock problem with sequence-dependent cut losses. International Transactions in Operational Research, 5-24.
Highsmith, J. (2013). Adaptive software development: a collaborative approach to managing complex systems. Addison-Wesley.