Published on May 28, 2020
Updated on May 28, 2020
Read time 8 minutes
A Comprehensive Guide of the Software Development Life Cycle
If you have been working as a software professional in the industry for a day or a lifetime, then you probably know that the Software Development Life Cycle is part of the daily rituals.
Assuming that you don’t know anything about SDLC or software development life cycle, this article will fill you in on everything you need to get started. We talk about SDLC in general; what it is, how it works, what are the phases that it goes through. In addition, we also look at a few software development lifecycle models that help to refine the overall workflow.
What is the Software Development Life Cycle?
The Software Development Life cycle or SDLC is a thorough process to manufacture software that systematically ensures that the quality and the correctness of the software is according to the standards set by the company and the industry.
This life cycle aims to ensure that the software’s that are being manufactured in the industry are properly falling under the expectation bracket of the customer. One thing it ensures is that the development process of the software stays inside the already agreed upon cost and time frame.
The software development life cycle is a compilation of ideas and plans that explain the whole process of planning, building, maintaining software from initiation to completion. And it’s not a stagnant process either.
In every step of the way, some various processes and deliverables need to be worked on, to make sure that the next phase of the lifecycle goes smoothly.
Why use SDLC?
The following are a few of the reasons why we SDLC is important to produce software.
- It offers a basis for project planning, scheduling, and estimating
- It is a mechanism for project tracking and control
- Increased and enhance development speed
- Helps you to decrease project risk and project management plan overhead
- Provides a framework for a standard set of activities and deliverables
- Increases visibility of project planning to all involved stakeholders of the development process
- Improved client relations
What are the Phases included in the Software Development Lifecycle?
The whole lifecycle is divided into the following stages. They are:
- Requirement collection and analysis
- Feasibility study
- Installation/ Deployment
Let’s dive into the details of these phases and find out how the software development lifecycle works.
1. Requirements Collections and Analysis
This is the first stage of the Software development life cycle which is executed by the most senior members of the development team. This execution is based on the inputs submitted by all of the domain experts and stakeholders connected to the industry.
One other important thing that is performed in this stage is the planning for the recognition of any potential risks and scope creeps, and the quality assurance requirements for the software in question.
This stage is important also because it makes the following entities connected to the project, quite clear. They are:
- Project Scope
- Anticipated Opportunities
- Anticipated Issues
- Anticipated Directives
Learn the complete process of project scope, here:
2. Feasibility Study
Once the initial phase in over where we look over the requirements and how the software is going to be planned, we move on to the next step where all of the software needs and requirements are put onto paper and properly documented.
This document that is compiled in this step is done so with the help of the Software Requirement Specification document. It is known as the SRS document. This document includes every information that is to know about the development process and how everything is going to be designed and developed within the project development lifecycle.
Mainly there are 5 different feasibility checks that every project goes through.
- Economic: Can this project be completed on the budget that the whole upper management and the stakeholders signed off on?
- Schedule: Decide that the project can be completed within the given schedule or not
- Legal: Can this project pass the cyber law requirements and other regulatory compliances?
- Technical: Need to check whether the current computer system can support the software
- Operation feasibility: Can we create operations that are expected by the client?
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In the next stage of the software development life cycle, all of the software design and system documents are created on the specifications and requirements provided in the requirement specification document.
What this does is that it enables the team to easily define every nook and cranny of the system architecture.
Traditionally, there are two different types of design documents that are created in this phase of the software development life cycle. They are:
High-Level Design (HLD)
- Brief description and name of each module
- Interface relationship and dependencies between modules
- Complete architecture diagrams along with technology details
- An outline of the functionality of every module
- Database tables identified along with their key elements
Low-Level Design (LLD)
- Functional logic of the modules
- Complete detail of the interface
- Listing of error messages
- Database tables, which include type and size
- Addresses all types of dependency issues
- Complete input and outputs for every module
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Once the critical design phase is complete, the team members now direct their focus to one of the most important stages of the software development life cycle and that is coding.
The task allocation is performed in this stage which lets all of the team members and the developers know what their goals and milestones are regarding this project. This is basically the longest phase of the SDLC.
When the coding is complete and the software has been completed, it is passed over to the realm of testing. This is where the testers test each nook and cranny of the software until they find issues and errors that are hindering a seamless execution of the software.
This testing is performed, to verify that the entire application is working without any hiccups according to the requirements provided to the team by the customer.
In this stage of the SDLC, the testing team finds all of the issues and errors that are putting obstacles in seamless execution of the software and when they find them, these errors or issues are communicated to the developers.
These developers fix these issues and send the software back to the tester to run a re-test. This process goes back and forth until finally, the software is free of any issues that hinder its successful execution according to the criteria set by the customer.
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Once the coding and testing of the software have been completed by the respective teams and departments, we move onto the final deployment process. The software in this deployment step is free of any bugs or issues and is finally released, based on the valuable feedback the team receives from the project manager.
Once the system has been successfully installed or deployed according to the feedback given by the project manager of the whole shebang, the customers start using the software that has been carefully and expertly crafted by the team members.
When that happens, the following three activities follow suit. They are as follows:
- Bug fixing – bugs are reported because of some scenarios which are not tested at all
- Enhancement – Adding some new features into the existing software
- Upgrade – Upgrading the application to the newer versions of the Software
What Are the Most Popular Models of the Software Development Life Cycle?
The following models are the ones that make up the whole SDLC. They are:
1. Waterfall Model
One of the most important models of the software development life cycle that is widely accepted across the board is the waterfall model. In this model, the whole bigger chunk of the software development process is broken down into tiny phases that the team needs to accomplish.
In this model, the outcome of the previous phase acts as an input for the next phase in the roster. One other thing to remember is that the waterfall model is very intensive when it comes to documentation. This means that the team has to document every phase as it comes along.
The next important model in the software development life cycle is the V-model. In this model, the phases are planned in parallel. This means that all the verifications that are needed and the validations that are necessary for the project are conducted on either the opposite side.
3. Agile Model
The Agile methodology is not only important but also comes with numerous benefits when it comes to software development or even when it comes to the project management paradigm as a whole. This methodology is a vital process that enables the interaction of two especially important phases of the SDLC process, which are testing and development.
In the Agile course of action, the whole big chunk of the project development process is divided into smaller builds that the team members can perform. These builds are performed in small iterations that are called sprints. These sprints can last from 1 to 3 weeks depending on the size of the team and the development process.
4. Spiral Model
The Spiral model of the software development life cycle is a risk-driven one. This helps all the team members to adopt one or more process models included in the software development life cycle’s arsenal like the waterfall, Agile or V-model, etc.
This strategy enables the team members to use all of the best features of every one of those models and use them to their advantage in the process of software development.
Based on everything we have talked about the software development lifecycle, some of the key highlights could be summed up as appended below. Bear in mind that SDLC is an ever-evolving phenomenon due to changing technology and industry needs. Feel free to improvise as a project manager – or a program manager for that matter.
- The SDLC is a systematic process for building software that ensures the quality and correctness of the software built
- SDLC process provides a framework for a standard set of activities and deliverables
- The senior team members conduct the requirement analysis phase
- In the Design phase, the system and software design documents are prepared as per the requirement specification document
- Testing is the next phase which is conducted to verify that the entire application works according to the customer requirement.
- Bug fixing, upgrade, and engagement actions covered in the maintenance face
- SDLC consists of a detailed plan which explains how to plan, build, and maintain specific software
- The full form SDLC is Software Development Lifecycle
- Seven different SDLC stages are 1) Requirement collection and analysis 2) Feasibility study: 3) Design 4) Coding 5) Testing: 6) Installation/Deployment and 7) Maintenance
- Feasibility Study stage includes everything which should be designed and developed during the project life cycle
- In the coding phase, developers start to build the entire system by writing code using the chosen programming language
- Installation and deployment face begins when the software testing phase is over, and no bugs or errors left in the system
- Waterfall, Incremental, Agile, V model, Spiral, Big Bang are some of the popular SDLC models
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