Once a wise man said: “If you fail to plan, you plan to fail”. The System development life cycle (SDLC) offers a structure to the challenge transitioning from beginning to the project end. There are various SDLC methodologies used to guide professionals using project-based work models. The Model specifies multiple stages of the process and how it can be carried out. Also, selecting the Model comes with a high impact on the testing.
Here, in this article, we’ll explore the different types of SDLC models, their advantages and disadvantages, and when to use them. One can think of SDLC models as tools that deliver the best software projects with understanding each Model and its usage.
What is the software process model?
A software process model is a kind of an abstraction of the software development process. The models specify the stages and process the order. Think of the software model as a representation of the order of activities that form the sequence. Generally, a model can be defined as:
- The tasks to be performed
- The pre and postcondition for each task
- The input and output of each task
- The flow and sequence of each task
Factors for how to choose a software process
Choosing a suitable software process model might be a tough job. If you know your requirements, it would be easier to choose the Model that best suits your needs. Check the below factors that would help you to select the best software process model.
- Project needs: Before choosing the Model, take some time in understanding the project needs. Clarify the organization and team expectations. The user needs to specify the requirement in detail after each iterative session. Check the requirement change during the development process.
- Project size: Choose the project size and work on large projects with bigger teams. Get more extensive and vast project management plans.
- Cost of delay: Check if the project’s high time-bound with a massive charge of delay along with timelines flexibility.
- Project complexity: We might not know about the project complexity, but it might require changing the cost of delaying work. Make sure your project needs constant monitoring or feedback from the client.
- Customer involvement: Check if you’re seeking to consult the customer during the process or need a user who needs to participate in all phases.
- Technology familiarity: It involves the developer’s knowledge and experience with the project domain, software language, and other methods needed for the development.
- Project resources: It adds the amount and availability of staff, funds, and other resources.
Types of Software Development Life Cycles
Waterfall model
The waterfall model is a plan-driven process, a sequential model scheduled for all activities before starting the project. Each activity comes in the waterfall model that represents a separate phase plotted in a linear order.
The waterfall model comes with the following phases:
- Requirement
- Design
- Implementation
- Testing
- Maintenance
- Deployment
Each of the above phases needs one or more documents approved before the next phase begins. However, the steps are likely to overlap the feed information that differs from one another. The Model is quite easy to understand and does not need customer involvement after the specification is done. There’s no way to try this Model until the last phase. The Model is very rigid in structure and should understand the need completely and unlikely to radically change.
V-shaped model
The V model is named the Verification and Validation model as it’s an extension for a waterfall model. One can gather the needs at the beginning as later it cannot be changed. One needs to have corresponding testing activity for each stage.
The Model is easy to understand, highly disciplined, and makes it easier for project management. It isn’t suitable for a complex project as there might be changing needs and unclear concepts. But the V model is the right choice for all software development for all downtimes and failed projects.
RAD model
The rapid Application Development process is an adoption of the waterfall model that targets developing software quickly. The RAD model is generally based on the concept that comes with a better system designed in lesser time and focuses on groups with gathering system requirements. The model includes:
- Data Modeling
- Business Modeling
- Process Modeling
- Testing and Turnover
- Application Generations
RAD may result in a low level of rejection compared to another model when placed into production. It uses the best approach that is especially suited for developing software that drives user interface requirements. Few of the GUI builders are called Rapid application development tools.
Prototype model
The Model works on the requirement gathering where the developer and user meet and define the purpose of software and their needs. With this, a quick design is created to focus on the aspects of the software that is visible to the user. It leads to developing a prototype where any modification or changes are needed to be made to the prototype.
This looping takes place with better versions of the prototype created. It allows users to add new changes updated in the prototype. The process would continue and satisfy their system. The prototype is later converted to the existing system along with all considerations for security and quality.
Spiral method
The spiral model is a risk-driven process like an iterative model that delivers projects in loops. Unlike other models, the phases address the problem that has the greatest risk of causing a failure. One can address the following stage for each cycle:
- Address the high-risk problem by determining the alternative solutions and objectives.
- Develop a solution by verifying if it’s acceptable.
- Evaluate the alternative by identifying the risk and offering possible solutions.
- Plan for the next cycle.
Iterative and incremental method
The incremental model allows stakeholders and developers to check results using the first increment. The developer only focuses on a clear and complete definition of the whole system before you start. The Model is great for a project with loosely coupled parts and projects with exact, precise needs.
While the Iterative model develops a system by building small portions of features where it helps to meet the initial scope and quickly release the feedback, once you start the implementation, all it needs is enhanced iteratively in the evolving version until the system is completed. The model process begins with a part of the software that implements and identifies the needs.
Similar to the incremental Model, the iterative Model allows checking results at the early stage of development. It’s a good choice for significant software development needs, which can easily be broken down into modules.
Agile development
The Model encourages continuous iterations of development. Each incremental part is designed & developed over an iteration designed for a small to extensive process and completed within a few weeks. The process mainly focuses on implementing a small set of features with minimizing the documentation of using informal communication. Check the following things we need to consider for using the Agile development process.
- Requirement assumed to change
- The customer involved during each iteration
- The system evolves over a series of small iterations.
- Documentation did when needed.
The agile process comes with a realistic approach that isn’t very complex. Its present challenges during the transfer phase where very little documentation is needed. They commonly use agile methodologies including Scrum, Extreme Programming, and Kanban.
What to learn next?
Excellent, you have made it to the end. Hope the above types of models have a better understanding of what software models work better for you. Here at Agile Infoways, we have several SDLC options depending on the number of projects. Most often, our tasks are performed using more flexible models for the optimal software development process.
To summarized each model, below we have shown its benefits-
- The waterfall model is used for smaller projects, but needs are precise and unnecessary to change quickly. Each stage is well-defined and is very easy to understand.
- The incremental and iterative models are a good match for massive projects where initial versions of the software are generated at first.
- Agile Models are best suits for small to medium-sized projects where rapid changes are required. The customer is involved in each stage which saves time and money.
- In the prototyping model, one can visualize some software ingredients, which help avoid misunderstanding between the client and the development team.
- The Spiral model helps to combine the elements of the prototyping and waterfall model. The method is suitable for large, complex, and expensive projects.
Agile Infoways is here to offer you the best IT engineers devoted to propelling the project forward through each iteration. The choice of choosing a methodology would depend on the unique interest and tasks. Get in touch with our experts and get the best in return.