Phases of Software Development Life Cycle (SDLC) Models

The software development life cycle, or SDLC, is a project management concept that discusses the various stages encountered while developing an information system. It defines the various steps of completing a project, beginning from the idea conception stage and leading to the project deployment, implementation, and future maintenance steps. In the information technology sector, the SDLC model is commonly applied to the development of hardware or software. If solely concerned with the development of software, the SDLC model is referred to as the software development life cycle.

The SDLC model includes various steps which are often completed iteratively and lead to the development of a robust and efficient system. The original SDLC variant, described as the Waterfall model, includes seven distinct steps. Eventually, other SDLC models have also emerged such as the rapid application model, the fountain model, and many more. However, one of the most commonly used SDLC variants nowadays is the Agile model of software development. Here we provide you with a comprehensive discussion about the seven original phases in the original waterfall model and how they are modified to give way to the Agile model.

Here are different stages of a Software development life cycle (SDLC);

The SDLC process includes seven primary stages, each of which is concerned with a different phase of an efficient product development process. These stages are described as:

• Planning stage – It is the phase in which the system developers sit together to identify and define the problem and assess if any of the existing systems can help address the same. In case of the unavailability of any such existing system, the planning team will be responsible for demarcating the various objectives of the software development project that they have to undertake. During this phase of an SDLC, the developers prepare an outline and schedule for the project which helps them ensure that the development process remains on track and any issues are detected before it impairs their productivity or efficiency. In this stage, the developing team also sketches out the budgetary and other resource requirements of the software development process.
• Requirement gathering and analysis – In this phase, all necessary information about the customer’s demands and requirements are collected. Here, the business analysts and product developers identify the product requirements based on the end-user specifications and the purpose that the product is meant to serve. It is a key stage of the product development process in which the developers are required to address any ambiguities surrounding the product idea and functionality. In this stage, some prototypes may also be developed. The requirement data gathered in this stage is depicted in the SRS document.
• Design – In this stage, the developers address the various design aspect of the product or the application and convert the observations noted in the SRS document into a comprehensive program or code. Here, the developers create the product’s various user and system interfaces, and its databases and address its network requirements.
• Development stage – Based on the design document obtained at the end of the previous stage, the developers now write the source codes for each of the various product components. In this stage, the developer essentially designs the actual application which meets all the criteria outlined in the prior stages. Here, the developer must focus on any code requirements specified by the clients and choose a programming language that best serves the purpose of the product.
• Testing stage – It is a crucial step in the software development process. Here the integrity and functionality of the code written by the developers are tested to determine if the system serves the necessary purpose it is meant to serve. In this phase of the SDLC, the developers intricately analyze their program and detect any bugs or drawbacks that must be addressed. This step is significant because it enables the system developers to maintain the integrity and quality of the product.
• Implementation/ deployment phase – After being tested, the system is integrated into the product scenario or a hypothetical production environment where it will be tested against customer expectations. In this, customer usability/acceptability is also assessed. By the end of this phase, a product is ideally ready for market launch.
• Maintenance – It is the final stage of an SDLC process where the product/system developers shift to a product maintenance mode. In this stage, the developers address customer grievances and are responsible for introducing suitable changes in the program whenever necessary.

The waterfall model of SDLC

The waterfall model was the first process model of SDLC to be introduced and is also referred to as the linear-sequential life cycle model. In this model of systems development, each phase must be duly completed before initiating the next phase. The various phases of the SDLC are arranged sequentially where each stage is initiated only after the completion of the previous stages. This model initiates with the completion of the product planning stage and begins with the requirement gathering and analysis stage. All other stages described above followed suit and in a linear/sequential pattern. The waterfall model has its inherent advantages and disadvantages.

Advantages of the waterfall model –   

• This model is easy to use and implement
• Due to its inherent rigidity, each stage of the model has specific deliverables which allow adequate performance review and analysis
• It works especially well for smaller projects
• The process results are easy to understand and assess

Disadvantages of the waterfall model – 

• No functional product or system will be released until much later in the SDLC process.
• It is not suitable for complex and object-oriented projects.
• It is a poor choice for undertaking prolonged and ongoing projects or processes.
• The model has high levels of risk and uncertainty as any testable product is not available until much later. Any revision in product design would thus lead to the utilization or wastage of a substantial amount of resources.
• This model does not accommodate changing requirements as the entire process relies on the initially developed SRS document.
• As the product is implemented at the end of the development process, it prevents early detection of any functional shortcomings or challenges.

Thus, the waterfall model represents the original SDLC concept which is best suited for simple and small-scale projects. However, this particular model fails to accommodate the increasing complexity of the modern-day business environment and is not suitable for implementing large-scale complex projects. 

The agile model of SDLC

The waterfall model of SDLC, although simple and easy to manage, did not meet the performance standards of the contemporary commercial world. To fulfill its drawbacks, especially for long and complex projects, emerged the concept of the agile SDLC model. This SDLC model is unique in the fact that it allows the due modification of the software development life cycle as per the specific needs of each new product. Instead of following the sequential process development strategy of the waterfall model, the agile model allows the division of the entire SDLC process into small time frames, during which some specific features or components of the product will be released. The key differentiating factor of this SDLC model is its iterative approach. In each iteration, a software development cycle takes place, and a partially functional system or software is produced. At the end of the final iterative phase, the finished product with all its features is produced and marketed. This model also has its inherent pros and cons which are discussed below.

Pros of the agile model – 

• It is a realistic project management approach that allows the stagewise development and testing of the product.
• It promotes efficient teamwork 
• This is a good model for constantly changing or evolving product or system environments.
• It reduces the planning requirements of the ADLC process.
• The resources and budgetary requirements of the entire SDLC process are distributed among each iterative phase, leading to the easy management and flexible operation of the development system.

Cons of the agile model – 

• Despite the minimal planning requirements of this model, an overall plan and agile project management approach are essential for the suitable execution of the process, in the absence of a suitable organizational culture, the SDLC could become disoriented and lead to disarray.
• Due to the discontinuous nature of the process, the agile model is highly dependent on individual efficiencies and the customers’ capability to communicate the needs of the project. Any miscommunication between the developers and the customer can lead to the summary disruption of the entire SDLC process.

Examples of the types of software development life cycle (SDLC) assignments;

• Network Protocols and SDLC
• Assignment On Network Protocols And Sdlc
• NETWORK PROTOCOLS, SDLC & ITSM.
• Agile And Sdlc Assignment Analysis
• SDLC Security Model - Report
• NETWORK PROTOCOLS, SDLC & ITSM.
• Option 1: System Development Life Cycle (SDLC): Student Database
• NETWORK PROTOCOLS, SDLC & ITSM.
• Network Protocols, SDLC & ITSM.
• IT FUNDAMENTALS: NETWORK PROTOCOLS AND SDLC.

To conclude, the Software Development Life Cycle is a key concept of the project management process and is often undertaken following various us models. For a simple project, the waterfall model is duly suitable while the agile model is suitable for addressing the advanced needs of a complex software development process. Whatever your product development needs are, choose your SDLC model accordingly.