Software Development Life Cycle Phases & Models

SDLC is the process of development for software products. It is also known as the development lifecycle and it involves various phases such as requirement analysis, design, development, and testing. Software Development Life Cycle includes the steps taken from inception to final delivery, and it can be used as a part of the project management methodology. SDLC helps in achieving the desired result, reducing time to market and reducing the cost of development by improving quality.

Phases of Software Development Life Cycle

Software Development Life Cycle Phases

1. Requirement Analysis

Requirement analysis is the first step of SDLC. In this, you collect and analyze user needs, business goals and objectives, and other stakeholder requirements. You also create a complete list of all the features that will be included in your project.

2. Planning

Planning is the process of defining the goals, objectives, activities, and timelines for a software development project. It plays an important role in SDLC as it helps in identifying the need for further analysis and design phases.

Planning consists of the following activities:

• Understanding the business needs of stakeholders and users.

• Identifying appropriate approaches.

• Establishing an appropriate project structure including teams and roles, responsibilities, communication channels, etc.

3. Designing

Designing is a phase where the details of how the software should function in order to meet the requirements are planned out. Depending on the project, these details can include screen designs, databases, sketches, system interfaces, and prototypes. Clients use these details to make final product design choices.

During this phase, the 3 major aspects of software namely View, Model, and Function are detailed for every feature that the software is supposed to provide. For instance, in a web application, View designing activity includes the user interface part of the software i.e. content styling (fonts, color, etc), content matter & arrangement,  image selection, etc. Model designing involves preparing definitions for a data structure (how data is handled) and database (how data is stored). Function designing consists of activities that prepare business logic (flow of control) and the User Experience user interaction methodology. 

The designing of the User Interface known as UI (ie. View) and User Experience known as UX (Functional part of the View) go hand in hand and involve decisions from stakeholders of the software. Business logic and Model development are more developer intensive. One of the main parts of the Model is the Database. Database design is the definition of how database tables and fields are organized. Business logic is a collection of executable programming code that makes decisions based on the user input (via View) and Current State (via Model). So there are various programming paradigms to choose from. The most popular one in web application designing is the object-oriented programming paradigm. Object-oriented design is a method for designing programs that break down complex problems into smaller, more manageable ones. The designing phase may sometimes involve the creation of a functional prototype as a proof of concept. This is a good way to test a concept before the start of coding. 

The design stage includes:

• Analysis of business requirements.

• Analysis of system requirements.

• Designing the architecture, user interface, and data structures of the system.

• Implementation of these designs in code/models (based on programming language).

4. Coding And Unit Testing

Coding is the process of writing source code. It involves creating a program or software, usually by combining several modules that perform discrete functions. After coding, it must be compiled and linked to create an executable file for use on a computer system or network.

Unit testing is a type of software testing that tests individual units of source code to determine if those units meet their design and functionality requirements. Unit testing can be done manually but is often automated with tools such as unit test frameworks or record-and-playback tools.

5. System Testing

System testing is the process of testing a software application as a whole. It is usually performed to verify that the software meets the requirements, to ensure that all components function together, and to detect where further refinement is needed. System testing is usually performed after unit testing and before acceptance testing.

System testers plan, design and execute tests that are used to determine whether or not an application works as expected, using various test cases based on requirements defined by business analysts who understand both technical and business aspects of a project; developers create code that represents those requirements; system testers then write tests based on those specifications in order to test all possible scenarios within their scope (which may include input values, database queries, etc).

6. Deployment 

Deployment is the last stage of the software development lifecycle. It’s the process of making a software product available for use by end users. It includes all activities which take place after the testing and validation of a product or system. In deployment, the software is installed on the target platform, tested, and documented. It is different from installation because it involves transferring the product to an end-user environment, whereas installation involves transferring it to an execution environment on a developer’s machine.

A part of the deployment is a phase known as Staging. Staging is essentially deploying the software into a mock environment for the use of the decision-making stakeholders of the software. Staging is one of the most important stages in SDLC as it provides an opportunity to test whether the developed software meets its requirements or not before the final deployment. If there are any issues with the developed software then they can be resolved before moving forward to Operations ie. in the use of the software in the user environment.

7. Operations and Maintenance

The Operation Stage is the final stage of the software development life cycle. The operation stage is where the software is finally deployed and put into use by end users.

The following are some of the key activities that occur in this stage:

• The final system functionality is tested by end users to ensure that it meets their needs.

• A decision is made about whether or not to deploy one or more releases of the software.

• System administration tasks are performed, such as installing updated versions of operating systems and application packages, configuring security settings, and setting up backups.

• User training is provided so that end users can become familiar with using the system effectively.

• Support contracts are established for ongoing maintenance and support of the system throughout its lifecycle.

• Maintenance is the process of modifying software to correct defects, improve performance or other attributes, or adapt to a changed environment. Maintenance generally focuses on modifications to existing software that fix bugs or add features without changing the underlying design of the system. Maintenance aims to keep software functional, and effective, and provide compatibility with newer versions of hardware and software.

• Maintenance occurs in the initial release of a product or service and continues through its expected useful life. Maintenance may be performed by the original developers, or by other developers who specialize in maintaining systems they did not build. The frequency of updates varies widely across systems, from daily updates to annual updates. 

Maintenance activities include:

• Refactoring code to improve readability or maintainability

• Fixing bugs that were discovered in testing or by end users

• Adding new features requested by users

• Upgrading the system from one version to another

Software Development Life Cycle Models

There are several software development life cycle (SDLC) models that have been developed over time. The following steps will walk you through each of these models which has its own advantages and disadvantages:

softwaree development life cycle models

1. Waterfall Model 

This is a sequential model where all tasks are completed before moving on to the next phase. It’s considered highly structured with strict rules on what happens when. However, it can be difficult to manage complex projects using this approach without creating additional layers of management or having too many people assigned to each task at once.

The advantage of the waterfall model is that it provides a good structure for managing large projects, which helps to manage the complexity, risk, and uncertainty associated with software development projects.

The main disadvantage of the waterfall model is that it doesn’t allow changes or enhancements to be made once the design is done and the development is underway. One needs to have a thorough knowledge of the entire software before attempting development.

2. Iterative Model

The iterative modeling approach to software development is designed to reduce risk and provide flexibility by allowing changes to be made at any point in the process. In this approach, the phases are repeated until all requirements are met, but each iteration takes less time than the previous one because the developers know which iteration of a project works better than the preceding one. The advantage of iterative development models is that they allow for changes to be made during or after each phase, greatly reducing risk and cost.

The advantage of an iterative model is that it creates a good working environment for developers and testers to work in as they can see their work being used by other people throughout the project. This way they can fix bugs as soon as they come up instead of waiting until a later stage when it is too late to change anything without affecting other parts of the application. 

The disadvantage of this model is that it can take longer than a waterfall because each step needs to be tested thoroughly before moving on to another step.

3. V-Model

The V-model extends its predecessor by adding a verification stage at the end of each planning phase and it is an extension of the waterfall model. It was designed as a way to better manage the complexity of large projects by breaking them down into smaller phases with clear objectives, deliverables, and deliverables. This allows companies to tailor their own process based on their individual needs while still maintaining some standardization across projects within an organization.

The advantage of this model is that it provides a clear understanding of all the phases involved in the software development process.

It reduces the risk of failure at any stage by identifying issues at an early stage. It also allows you to identify problems in time so that they can be resolved before they become major issues later on in the project lifecycle.

It enables you to plan and control resources efficiently as each phase has a specific time duration for completion which helps in better resource allocation and utilization across different phases of SDLC

Disadvantage: It does not provide any guidance on how to manage resources during each phase of SDLC which leaves it up to individual companies or teams to decide how much time will be spent on each phase based on their own

4. Big-Bang Model

The big bang model is a software development life cycle (SDLC) in which the entire system is developed at once. This approach may be used when the system requirements are well-defined and there are clear objectives for the project.

A big bang model is a waterfall approach that involves completing each phase before moving on to the next one. Each phase is typically linked to requirements gathering, design, development, testing and implementation.

The big bang model has some advantages over other approaches. It allows you to plan tasks in advance and implement them in an efficient manner. This can lead to better results because there is less room for errors or changes in direction during development.

The big bang model also allows you to test your application as soon as it’s finished, rather than waiting until after all features have been implemented. This means you can make improvements without having to wait until later on in development or rework parts of your code that aren’t working correctly or efficiently enough yet.

The disadvantage of this model is that it’s very inflexible. If something goes wrong later in the project, there’s no easy way to fix it except by going back to an earlier stage and doing something differently (which may mean throwing away work done so far). Also, if someone thinks up an idea later in the project that would have been useful earlier on, they may not be able to implement it using only this type of model

5. Incremental Model

The incremental approach is more suitable for complex, large-scale projects. The incremental development process involves defining the system requirements in detail and dividing them into smaller tasks that are then assigned to individuals or teams. These teams work simultaneously on different parts of the project until they are completed. This allows you to deliver usable software at an early stage of development, thus saving time and money by avoiding rework caused by issues identified late in the project life cycle.

The advantage of this approach is that you get to see your product evolve throughout its development cycle, which allows you to make changes if they are needed before they become too costly. It also allows you to add new features without a large time investment.

The disadvantage of this approach is that it can take longer than a waterfall model because there are many small steps involved in each phase. This means that your team will spend more time communicating between each other and waiting for feedback from different team members.

6. Agile Model 

This is an iterative approach that focuses on the rapid delivery of working software rather than trying to plan everything up front in detail before implementing anything new or changing anything old. It’s considered less structured than the waterfall model, but it’s also easier to adapt if things go wrong along the way due to changes in requirements or other factors affecting projects like unexpected delays caused by external factors.

Advantages: The first advantage of the Agile method is it has short release cycles. The Agile method is more flexible and can be easily adapted to changing requirements. It encourages collaboration between the customers and developers.

Disadvantages: There are some disadvantages also in the Agile Model it does not give enough time for proper documentation or documentation which is not complete as per the requirements, it cannot be used when there are many dependencies between tasks, and a lot of time is required to complete each task, etc.

Challenges for SDLC

The SDLC is a process through which the software development team goes through in order to build and deliver a product. The process involves several important steps like requirements gathering, design, coding, testing, and deployment.

At each step in SDLC, there are various challenges and risks that can impact the overall performance of the project. So it is very important for any organization to understand these challenges so as to overcome them in order to achieve better results. Automation plays an important role here as it helps us with developing strategies that will help us reduce our efforts while working on development projects thus improving our overall productivity.

The Role of Automation in Software Development Life Cycle(SDLC)

There are several reasons why software development organizations implement automation into their SDLC. The primary reason is to improve quality and reduce defects. Automated testing can be performed more frequently than manual testing, which means that the automated tests will identify issues earlier in the SDLC where they are easier to fix.

Automation also enables organizations to release new versions of their software more frequently. Since automated tests run very quickly (often in minutes), they enable organizations to increase the cadence of releases, thereby reducing the risk of releasing a version of the software that contains a critical bug. Moreover, when automated tests are written for each feature being developed, it allows developers to focus on developing new features instead of writing code for regression testing purposes (which is often necessary with manual testing).

In addition to improving quality and increasing cadence, automation also helps reduce costs associated with developing software. By leveraging automation tools such as Selenium WebDriver or Robot Framework, developers can spend less time performing repetitive tasks that are required during manual testing activities such as clicking through web pages or filling out forms on the screen. Instead of having humans perform these types of tasks over and over again during manual testing activities.

Conclusion

The software development life cycle is a systematic process that helps guide the software development team (both software developers and project managers) through the organization’s goal of producing successful software products. This process addresses all aspects of delivering a quality product, including initial requirements, design, implementation and testing, integration, deployment, support, and maintenance. The SDLC serves as a roadmap to help navigate an organization through the development of software products. We strive to make our software products successful so they can meet the goals of our clients and customers.