A process used to design, develop and test the high quality of software is known as the Software Development Life Cycle. SDLC is acronym used for Software Development Life Cycle i.e. also called as Software Development Process. SDLC is used by industries to produce high-quality software that meets customer expectations and provide fast delivery. SDLC is used to flag the errors in the software creation process before they are discovered in the previous stages.
What is SDLC?
SDLC defines different tasks to be performed in each step of software development. The life cycle defined the quality and efficiency of software to be developed in the process. The various stages of SDLC are shown in the image given below:
Stage 1: Planning
Planning is the basic fundamental stage where the process starts. Senior members of the team involved in this stage. They performed it with inputs from the customer, and sales department work on it by doing market surveys and discussions with the domain experts in the industry.
This information is then used to plan the basic project approach that how the project will be developed and their feasibility according to the economic, technical and operational areas. How the project will be designed and what will be required in the whole process of project development is decided in the planning stage. Also, the risk associated with the project will also be defined in this.
Stage 2: Requirement Analysis
The customer will give all requirement that what they want in the project and what will be the flow of the project. All requirement will be then defined and documented and then this will be approved by the customer and the market analysts to make sure that product which is to be developed is useful for the industry. This all is documented in a format which is called SRS (Software requirement specification). This SRS report consists all the required details which are required in the whole process of software development life cycle.
Stage 3: Software Designing
Designing is the reference to start the development of the product. This will be followed when the best architecture to be developed in the step by step process. When we prepare the SRS report, this is proposed in that more than one design approach for the project to be followed and documented in a Design Document Specification (DDS). DDS is sent to the stakeholders and reviewed on the different parameters including design modularity, risk assessment, budget and time constraints, product robustness, and last but not the least this keeps in mind that the best design approach is selected for the project. Project’s data flow representation with respect to architectural modules also represented in this stage. DDS is the document which had to be followed in the coming stages so this should be clearly defined all the architecture with the minutes of the details in it.
Stage 4: Software Development
From this stage, the actual work starts with the coding or programming. The codes are generated as per the DDS in this stage. If the DDS is prepared very carefully and all designs are in an organized manner then the code can be generated without hassle.
The process success depends on the developer should be skilled and expert. He / She must know how to follow the coding guidelines and programming tools like interpreters, compilers, and debuggers. The programming language which is to be used decided as per the project requirement.
Stage 5: Software Testing
When the project is ready with the design and code, then this stage of testing will occur. Usually, testing is the part of all stages in the modern approach of SDLC. However, in this stage, the final product is to be tested where the product defect is reported, if any. The defect will be tracked, fixed and retested to remove to give the product as per the quality standard.
Stage 6: Software Deployment
When the product testing is done and all bugs are fixed the product is ready to be deployed in the appropriate market. Sometimes product deployment is done as per the strategy of the organization. The product is released in the selected segment to test its response in the real environment which is known as UAT (User Acceptance Testing). If the result received as positive then it is released in the whole segment and if there is any enhancement suggested, the product will be released after the changes applied.
SDLC Models
SDLC is the industry standard approach used to manage the phases of an engineering project. In the common methods, SDLC includes () models that are used to trace a project from the planning to final release including operation and maintenance. Here are the different models or methodologies that are used in SDLC approach.
1: Waterfall SDLC Models
Waterfall model is considered as the oldest method used widely for SDLC methodologies. Waterfall model is a straightforward approach and a structured model. But in recent years, the popularity decreases of the waterfall model. This model has a rigid structure that strictly allows being followed the steps as given in the above picture. In the very initial stage the requirements to be defined in this model. Only after that, the process starts. This is the downside of this model.
Each stage is to be finished to go to the next stage. This model is not useful if the flexibility is needed and the project is for the long term. But waterfall is still a strong solution for government contractors.
2. Iterative SDLC Models
The other model in SDLC is the Iterative model. This model is the repetition incarnate. This does not start with the known requirements. Unlike the other models, in this development team initialize the software requirements and test and evaluate them for finding further requirements. And then the design and implementation phase is executed. After each step, the new version of the software is produced. Improvements are applied in each iteration until the complete product is ready. The main advantage of this model is the customer gets the working version of the project in the early stages of the process.
The iterative model is same as agile except the external involvements are less scope of each increment is fixed. The popular example of the Iterative model is IBM’s Rational Unified Process (RUP).
3. Agile SDLC Models
The agile methodology is the opposite of the waterfall model. The difference is rather than focuses on requirement analysis, design, and testing, an agile model makes them all in an ongoing process which is done by the involvement of management, developers, and customers. Initially work is broken in segments called “sprints” and the responsible team tackles the needs of the particular segment with their customers and performs testing. Agile works well where speed and flexibility is the need of projects like in small organizations and startups.
4. Lean SDLC Models
The lean methodologies are inspired by lean manufacturing practices and principles which are:
- Eliminate waste 2.Amplify learning
- Decide as late possible
- Deliver as fast as possible
- Empower the team
- Build integrity in
- See the whole
Lean is closely interconnected with Agile as they both focused on speed and flexibility for continuous improvement. Lean is mainly work on which it must be worked at that time. Teams are also focused to cut waste and finding opportunities at every turn throughout the SDLC process by dropping the unnecessary meetings to reduce the documentation timing. The major difference in agile and lean with respect to customer satisfaction is agile give the top priority to the stakeholder feedback and lean emphasizes the elimination of waste to create more value for a customer that enhance satisfaction.
5. Prototyping SDLC Models
As the name specifies, in this model the team focus to produce an early model of the product, system, software or application to be developed. This is not completely fully functional or tested, but it’s only to give the customer an idea about what’s to come. According to the feedback of the customer on the prototype model, the team implements the product by following the rest of the SDLC phases.
6. Spiral SDLC Models
The spiral model allows teams to take the multiple SDLC methodologies on the risk pattern of the given project. When the team chooses the iterative and waterfall model, they have to face the challenge that to know when is the right moment to move to the next phase. The organizations that are not sure about their requirements or modifications during their risk analysis can go with this methodology. This is the most flexible approach. In this project passes through 4 phases allowing for multiple rounds of refinement:
- Determine Objectives
- Identify and Resolve Risks
- Development and Test
- Plan the next Iteration
Risk management is another benefit of spiral SDLC approach. This is typically used by large organizations.
People Also Read: What is RAD?
7. DevOps SDLC Models
DevOps is the latest methodology to the SDLC models and for the newcomers. Now, this method is adopted by many software companies and IT organizations. As the name specifies, the purpose of this model is to bring the development teams together with the operational for streamline delivery and support.
The advantage to using this model is an organizational risk is reduced and changes become more fluid. Amazon Web Services says about DevOps methodology: “DevOps is the combination of cultural philosophies, practices, and tools that increase an organization’s ability to deliver applications and services at high velocity: evolving and improving products at a faster pace than organizations using traditional software development and infrastructure management processes.”
8. V-model SDLC Models
The development in the classic waterfall model came out to be as V-model. The difference is that the testing phase associated in each development stage of V-model. V-model is known as the Verification and the Validation model also. In this model, the process happens in a sequential manner that is V-shape.
In the V-model, the testing phase is planned in parallel. Therefore, the verification phase is on one side of the ‘V’ and validation phase is on the other side of ‘V’. The advantage of this model is that a highly disciplined model and very effective for smaller projects where requirements are very well understood.
Choosing the best SDLC model When you choose the best SDLC approach for your organization it is important to remember that one solution may not fit in every scenario. So consider to discuss with an expert IT analyst and do the proper research.
You can also read it here.