Software development existence cycle models are frameworks that manual the development of software program tasks from start to completion. There are several software development existence cycle fashions, every with its personal set of benefits and drawbacks. In this answer, we will compare some of the maximum popular software development life cycle fashions, inclusive of the Waterfall version, the Agile version, and the Spiral version.
Waterfall Model
The Waterfall model is a linear and sequential model that follows a strict series of steps inside the software improvement system. It includes five levels: Requirements accumulating and analysis, Design, Implementation, Testing, and Maintenance. Each phase has to be finished earlier than transferring on to the next phase. The Waterfall version is useful while necessities are truly defined, and modifications are not likely to arise in the course of the task. However, this version isn’t always desirable for projects that require flexibility and steady changes. It also can be hard to perceive issues early on in the manner.
The Classical Waterfall Model
The classical waterfall model is a linear model of software development that was introduced in the 1970s. It divides the process of making software into separate phases that must be done one after the other before going on to the next phase. The model was based on the way that manufacturing and building work is done in steps. There are several phases of the Classical waterfall model.
- Gathering Requirements: Project requirements are acquired from the client or stakeholders at this phase. The requirements are analyzed for further scopes, scalability, and potential risk.
- Designing System: This phase includes the high-level and the low-level design specification of the system’s architecture.
- Implementation of Software: During this phase, the physical coding of the software takes place. Programmers develop code in accordance with the design specifications. This stage leads to the development of software modules and components.
- Testing of Software: The software is tested properly the defects, bugs and errors. Several kind of testing is performed like Unit testing, Integration testing and system testing.
- Deployment of Software: On ce the software testing is properly done, the software is deployed to the production environment for the end user.
- Maintenance of Software: This is the last and the final phase of the classic waterfall model. In this phase the ongoing maintenance and the support of the software occurs.
Advantages of the Classical Waterfall Model
- Clear and Structured process: The model is very straightforward and it is very easy to implement.
- Documentation: Each phase requires documentation, which aims in better understanding, knowledge transfer between the team members.
- Well suited for small project: Classic waterfall model works good for the small project
Disadvantages of the Classical Waterfall Model
- Inflexible: The sequential nature of the model makes it inflexible to changes. If the requirement changes after the project goes to the next stage then it becomes so time consuming and cost effective to rewrite the new changes.
- Variable demands are hard to meet: This technique assumes that all client needs can be precisely specified at the outset of the project, yet customers’ needs change with time. After requirements definition, amendment requests are tough.
- Late detection of Defects: Defects are not detected until the testing phase comes into picture and after that resolving that particular defect becomes costly.
- Risk management: The model’s structure can lead to a lack of proper risk management.
The Iterative Waterfall Model
The iterative waterfall model is the modified version of the classical waterfall model. The iterative waterfall model follows the sequential software development process. In the traditional Waterfall Model, each phase is finished before going on to the next one, and there isn’t no such scope to go back to phases that have already been done. On the other hand, iterative waterfall model uses “iterations” to let comments, changes, and improvements happen during the development process.
- Gathering Requirements: Similar to the classical waterfall model, project requirements are acquired from the client or stakeholders at this phase. The requirements are analyzed for further scopes, scalability and potential risk.
- Designing System: This phase includes the high level and the low level design specification of the system’s architecture.
- Implementation of Software: During this phase, the physical coding of the software takes place. Programmers develop code in accordance with the design specifications. This stage leads to the development of software modules and components.
- Testing of Software: The software is tested properly the defects, bugs and errors. Several kinds of testing is performed like Unit testing, Integration testing and system testing.
- Evaluation Phase: Iteration comes into play at this point. Instead of putting the software into use right after testing, stakeholders look at it. Feedback is collected, and any changes that need to be made are found.
- Adjustment Phase: In the adjustment phase, changes are made to the software, design, or requirements based on the comments and evaluations.
- Reiteration: Reiteration happens allowing for incremental improvements based on stakeholder feedback and changing requirements.
Advantages of the Iterative Waterfall Model
- Incorporating Feedbacks: In traditional waterfall there was no option for the feedback but Iterative waterfall model gives the privilege of working the feedback provided from one phase to the previous phase.
- Continuous Improvement: As the software is run over and over again, it gets better and better over time.
- More Flexibility: Compared to the traditional Waterfall Model, the model can better adapt to changes in needs.
Disadvantages of the Iterative Waterfall Model
- Increased Complexity: Keeping track of iterations and multiple rounds can make the project management process more complicated.
- Time and Cost: Iterations can take more time and cost more money if they are not handled well.
Agile Model
The Agile version is an iterative and incremental method to software improvement. This version is primarily based at the Agile Manifesto, which emphasises flexibility, collaboration, and rapid reaction to trade. Agile improvement involves the continuous delivery of running software program in brief iterations, commonly lasting from one to 4 weeks. The Agile version is well-desirable for initiatives with swiftly converting necessities or for groups that cost collaboration and communication. However, this model calls for an excessive degree of collaboration between group individuals, and it may be tough to control large projects.
Advantages of the Agile Model
- Flexibility: Agile projects has the flexible as they can easily change themselves for meeting new needs, goals and perform as per market condition.
- Frequent Deliverables: Agile projects help in producing software in shorter iterations, which overall impacts to see real progress and making changes easily.
- Customer Satisfaction: Agile helps in delivering useful features at a time, that gives customer more satisfaction.
- Continuous Improvement: Agile teams helps in continuously improving their processes and try to become more effective and efficient.
Disadvantages of the Agile Model
- Lack of Predictability: Because of the flexibility of Agile, it is difficult to get exact estimation of project costs, timelines for some long term project.
- Complex Project Management: Because of making of Agile in smaller steps, skilled management of project is required to keep project goals in mind.
Spiral Model
The Spiral version is a chance-driven version that mixes elements of each the Waterfall and Agile fashions. This model involves non-stop chance evaluation and mitigation for the duration of the software development manner. The Spiral version consists of 4 levels: Planning, Risk Analysis, Engineering, and Evaluation. Each section includes a combination of making plans, design, implementation, and trying out. This version is useful whilst managing big or complicated tasks where necessities aren’t nicely understood. However, the Spiral model can be time-eating, and it may be hard to decide when to move from one segment to another.
Selection of Appropriate Existence Cycle Model for a Venture
Selection of right lifecycle model to finish a project is the most vital assignment. It may be decided on via maintaining the benefits and drawbacks of diverse models in mind. The unique troubles that are analysed earlier than choosing a appropriate lifestyles cycle model are given beneath :
- Characteristics of the software to be developed: The choice of the life cycle model largely depends on the type of the software that is being developed. For small services projects, the agile model is favoured. On the other hand, for product and embedded development, the Iterative Waterfall model can be preferred. The evolutionary model is suitable to develop an object-oriented project. User interface part of the project is mainly developed through prototyping model.
- Characteristics of the development team: Team member’s skill level is an important factor to deciding the life cycle model to use. If the development team is experienced in developing similar software, then even an embedded software can be developed using the Iterative Waterfall model. If the development team is entirely novice, then even a simple data processing application may require a prototyping model.
- Risk associated with the project: If the risks are few and can be anticipated at the start of the project, then prototyping model is useful. If the risks are difficult to determine at the beginning of the project but are likely to increase as the development proceeds, then the spiral model is the best model to use.
- Characteristics of the customer: If the customer is not quite familiar with computers, then the requirements are likely to change frequently as it would be difficult to form complete, consistent and unambiguous requirements. Thus, a prototyping model may be necessary to reduce later change requests from the customers. Initially, the customer’s confidence is high on the development team. During the lengthy development process, customer confidence normally drops off as no working software is yet visible. So, the evolutionary model is useful as the customer can experience a partially working software much earlier than whole complete software. Another advantage of the evolutionary model is that it reduces the customer’s trauma of getting used to an entirely new system.
Frequently Asked Questions
Q.1: What is the basic difference between the Spiral and the Iterative model?
Answer:
The Spiral model combines iterative development with risk analysis, whereas the Iterative model involves repeating development phases.
Q.2: What is the Waterfall model, and how does it differ from Agile?
Answer:
Waterfall is a linear, sequential approach, while Agile is iterative and flexible, accommodating changes during development.
