Software Development Life Cycle (SDLC) Models & Phases

Software Development Life Cycle (SDLC) Methodologies & Phases in Software Engineering: The software development life cycle comes into the picture when you prepare high-quality software. Implementing this life cycle structure into our software development helps us get a quality product within a defined time.

Following different phases helps us find out where we need to improve to improve that point in future iterations to increase productivity and software quality.

If you look into the different stages of different methodologies, they are the same from one methodology to another. Sometimes, those phases or stages occur in order or mixed, and you may feel like some steps occur in parallel.

The workflow of SDLC may be involved in a repetitive transaction or the iteration of phases to get the final software.

SDLC Phases

Following are the best practices and stages of SDLC to ensure that the process works in a smooth, efficient, and productive way:

Requirement analysis
Architecture design
Feasibility study
Software development
Software Development Life Cycle (SDLC)
Software Development Life Cycle (SDLC)

Requirement Analysis Phase

This is the initial stage of the SDLC model, which is a planning phase. In this phase, collaboration happens between taking orders from the organization’s tech, business, and leadership minutes. and also some activities will be carried out in this stage, which include

  • Analyze and translate the business questions into engineering problems by considering cost, performance, functionality, and risk.
  • Evaluate the broad scope of the project to identify the available resources.
  • Consider project opportunities and risk across the technical and business aspects of every decision choice in SDLC phases.

The output of a requirement analysis phase is project plans, schedules, cost estimation, and procurement requirements.

Feasibility Study In Software Engineering

A document is prepared once the requirements are clearly understood from SRS ( software requirement specification). This document should be thoroughly followed by the developers and reviewed by the customer for future reference.

The feasibility study evaluates the following vital aspects, which are:

  • Economic: we are trying to find out if it is financially viable to invest in this project based on the available resources.
  • Legal: what is the scope of Regulation and the organizational capacity to guarantee compliance?
  • Operational: can you feel the requirement within the scope of the definition according to the proposed operational framework and workflow?
  • Technical: What is the availability of Technology and HR resources to support the SDLC process?
  • Schedule: can we finish the project on time?

After going through all the above vital points, the Executive Decision-makers should answer those book key questions and study them carefully before proceeding with the software design and implementation process.

If you follow the Waterfall model, the output will be a document listing all the requirements. But if you follow the Agile methodology, you will get a backlog of tasks.

Architectural Design Phase

Once the requirements are understood, software architects and developers begin designing the software. For the design of the software, the architect may use an architecture framework to compose an application by utilizing the existing components, promoting reuse and standardization.

Similarly, developers have started using some design patterns to solve algorithm problems inconsistently. In the design, the phase makes a model to represent how the software application will work. For that, this design phase has some key aspects, which include:

  • Architecture: architectures are responsible for defining the programming language, industry practice, overall design, and use of any existing template of the organization.
  • User interface: it defines how a customer interacts with the software and also how the software will respond to the inputs.
  • Platforms: here, we are considering the developed software that will run on which platform, like Apple, Android, and Windows version Linux.
  • Programming: Here, we define what programming language will be used, including the method for solving the problems and performing task applications.
  • Communication: here, we define how the application can communicate with other assets to search a central server, database, and separate instance of the application.
  • Security: Here, try to figure out how to secure the application, which may include an SSL certificate to the application, password protection, and secure storage of files & and credentials.

While taking into consideration all the points, a prototype can be prepared. This prototype is an earlier software version demonstrating how the application will look and work.

This design and the prototype can be demonstrated to stakeholders to get feedback or improve the application. Making a prototype is less expensive than rewriting the code to make a change in the development phase.

This phase’s output is design documents listing all the patterns and components selected for the project.

Software Development Phase

In this phase, the developers are started writing the code with the chosen programming language. If that’s a small project, then the complete system is handled by a single developer, but if that’s a big project, in that case, I broke off with several teams.

Suppose multiple teams are working on this project to develop the application. In that case, a source code management application will be introduced, which helps the developer to track the code changes.

Depending on the software testing methodology, if you are following a methodology, the timebox is divided with sprints, or if you are following a waterfall methodology, then the complete application will be delivered.

The development teams should produce software as quickly as possible regardless of methodology. Also, the business stakeholders are engaged regularly in the agile methods to ensure the expectations are met.

The output of this phase is testable and functional software.

Testing Phase

The testing phase is one of the crucial stages of the SDLC model. It is impossible to deliver a quality software product without software testing. A test plan was created based on the predefined software requirement during the testing time.

The test plan contains the availability of resources for testing, instructions, and assignments for testers. Also, the test plan includes what type of test should be conducted and which test reports should be delivered to the technical executive and decision-makers.

In the testing phase of SDLC, the developed software goes through a variety of testing to measure the quality of the product. which includes:

Code quality
Integration testing
Security testing
Performance testing

Automating all this type of testing without skipping is the best way to do this. To perform this type of testing, you can use the help of a famous automation tool like Selenium.

The output of this testing phase is functional software, which is ready for deployment to the production environment.

Deployment Phase

In the development phase, the application is made available to the end-user. Many companies prepare for the deployment phase. but before shipping or delivering the final product to the customer, there are some procedures and preparations of activities involved, like:

  • Documentation
  • Transferring ownership and licensing
  • Deploying and installing the product on the customer system

the output of this phase is software release to production of the working software.

Maintenance Phase

The development cycle is almost finished because the end customers have delivered and used the application. But still, the maintenance phase is critical because the end-user may have found some bugs not during the testing. These errors are to be resolved as soon as possible.

Besides bug fixtures, you can get additional feature requests for future releases. And each new release request launches a new development life cycle.

Advantages / Benefits of SDLC:

  • The SDLC process gives software developers and clients a clear and defined goal.
  • It provides a better understanding of how the project will be accomplished in phases or stages.
  • It facilitates planning, control, data management, technical guidance, and implementation processes of application development.
  • The SDLC guarantees better quality assurance factors and less rework.
  • The final product will be solid and reliable because it underwent intense testing in the development process.
  • It offers an organized approach that is easy to understand and less confusing for developers and clients.
  • Major roles are defined clearly during the SDLC, as their accomplishments are also defined.
  • Its structure can accommodate a team of people with different skills and expertise, having various roles to play in the project’s success.
  • SDLC allows for adjustments or changes in strategy, approach, or tactics even during development without affecting its successful outcome.
  • The SDLC facilitates software versioning as it has a proper version control system.
  • Better decision-making is possible because of accurate and detailed documentation that stakeholders and clients can easily access.
  • The Software Development Life Cycle promotes teamwork, synergy, and coordination among team members due to its clear definition of the responsibilities and accountabilities of each member involved in the process.
  • It ensures less costly and more cost-effective software development because all the costs from each project phase are included in the total budget.
  • The SDLC facilitates the smooth rollout of applications as it has a proper deployment planning system.
  • Application maintenance is also provided as part of the Software Development Life Cycle.
  • Modern SDLC is not limited to programming languages but can be applied in other domains like architecture and design.
  • A better understanding of a project’s scope, issues, and possible solutions is possible due to the clear definition of roles and responsibilities set in the process of SDLC.
  • There is less or no ambiguity in the responsibilities and accountabilities of each team member.
  • The software product’s quality is guaranteed because it is subjected to intense testing after each phase or stage of SDLC.
  • Compared to a non-structured approach or other software development process methodology, shortening development time is possible with a well-established Software Development Life Cycle.
  • There is a high level of predictability due to the involvement and collaboration of all concerned parties in the software development cycle.
  • It assures lesser cost overruns than a project without a Software Development Life Cycle or proper SDLCM implementation structure, processes, and procedures.
  • Applications developed following an established SDLC process are more reliable and less prone to errors or bugs.
  • It can be integrated into other software development processes like Software Engineering, Software Development Processes, Information Technology Service Management, and Project Management, among others.

Disadvantages / Problems / Limitations:

  • Often, the SDLC is implemented by project managers who are not technically sound in computer science. This often leads to poor project management due to the very technical nature of software development.
  • It is cumbersome and difficult to implement, especially for those who are unskilled or unfamiliar with this kind of methodology.
  • The SDLC can be applied only in small-scale projects with a defined scope, time frame, and budget.
  • It cannot be applied to projects that require flexibility, creativity, and adaptability, which are inherent to many innovative software developments.
  • The SDLC mostly applies to software development but can also be used in other disciplines like architecture and design.

Other SDLC Models

There are multiple software development models available, and various organizations follow those. Some of these models are:

Waterfall model
Iterative-incremental model
Spiral model
V-shaped model

Final Words

Planning to develop software always starts with a concept, and after that, it slowly goes through a series of phases from analysis to deployment. For the development of any software, we are following several methods.

However, two of these methods are mostly used by various organizations. One is the waterfall model, which is very common, and the other is the agile model, rapidly overtaking large and small companies. Whichever method you choose, use the right tool for the job.

It is very challenging to deliver software without following any method. Because we can say that there is no perfect method, but it’s far better to use a method than none.

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