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Software Development Life Cycle

What is the software development life cycle?

The software development life cycle, also known as SDLC or systems development life cycle, is a clearly defined and highly organised methodical process for developing and refining software.

The software development life cycle in generally described as in the following 7 stages – although there are multiple variations of this which combine some of the steps:

  • Planning
  • Requirements
  • Design and prototyping
  • Development
  • Testing
  • Deployment
  • Operations and maintenance

Software Development Life Cycle Importance

The software development life cycle is key for building software and ensuring the quality and correctness of the software built. It also helps to provide a framework for a standard set of activities and deliverables. 

If you are considering investing in an embedded software solution or mobile app that provides an exceptional user experience, then you will want to know the processes that are involved in building such a specialist product. 

This article will outline the software development framework and cover a detailed plan for building, deploying and maintaining the software as well as some of the common models utilising the SDLC.

Software Development Life Cycle Stages

Planning and Analysis

The first and most important stage of the SDLC is to gather all relevant information in regards to customer expectations, goals and objectives along with a detailed breakdown of what the customer wants to achieve long-term. 

At this stage, the project manager will set up a meeting with you to discuss these requirements such as what the purpose of the product is and who will be the end-user. The project manager will also help you to identify any potential gaps in the market. 

The meeting will also present a chance to discuss the opportunities and risks of pursuing the project. Clear structured documentation will help us to analyse the technical and economical aspects impacting the application development process. Involvement from our team will help calculate the ROI and determine the overall project cost and timescale for completion. 

Example: A customer wants to have an application that involves a tracking system to monitor and collect data. In this case, the stated requirements will need to be clear about what data the system will need to collect, how it will collect it and what the end results need to be.

Design and Prototyping

During the design phase, the conceptualisation of the solution is created. This will determine whether the software architecture is meeting the specific project requirements. Custom tailored software design by software architects helps us to set definitive workflows and standards. This stage of the process will be built using the final prototype and mockups, to check the functionality and usability of the solution and potential software development tools that can be used for the future development and processes to realise the business needs and objectives. 

There are two types of design documents developed in this phase; high-level design and low-level design. High-level design will include a brief description and outline about the functionality of each module, interface relationship and dependencies, database tables and complete architecture diagrams. Low-level design will assess the functional logic of the modules, database tables, complete detail of the interface, address all types of dependency issues, listing of error messages and inputs and outputs for each module.

Coding and Implementation

The implementation phase, also defined as the development and coding phase, is about writing code and converting all the design documentation into actual software and is the most lengthy part of the development process. 

The entire system will be built using the chosen programming language such as Javascript and all tasks will be divided into units or modules and assigned to various developers across the development team. 

The newly built and tested application is then moved to the testing and integration phase to deploy any immediate changes. The software engineering team has to make sure that the code meets all software requirements and specifications.

QA Testing and Integration

The software engineering team will then set out to deploy the software once complete into the testing environment. This is where the quality assurance testing team will set out and use a whole range of frameworks alongside unit testing to conduct a series of tests. 

Software quality assurance testing is an engineering process that ensures quality with all tests carried out in a robust testing environment, allocating time accordingly to each process, prioritising bug fixes and selecting the release criteria carefully. 

These tests include functionality testing, systems integration and user acceptance testing to ensure the code is clean and the business goals have been met. Once the system has been validated and is bug-free, the system will be ready for launch.

Support and Maintenance

During the final stages of the product development phase, there will be the opportunity for ongoing maintenance and support post-launch. Once the customer starts using the deployed system, any issues that may occur will be fixed. Maintenance support can be one of the following, including bug fixing, system upgrades or software enhancements. 

There could be a number of reasons that a software system may need maintenance including improving the design features for better usability or implementing enhancements or accommodating new programs so that different hardware, software, system features and telecommunications facilities can be used.

Software Development Life Cycle Models

In the software industry, the most popular software development life cycle models are the:

  • Waterfall model
  • V-shaped model
  • Iterative model
  • Spiral model
  • Big bang model
  • Agile model

Learn more about the popular models below.

Waterfall Model

The waterfall model, also known as the linear-sequential life cycle model, is a sequential software development process in which the steps flow steadily downwards (like a cascading waterfall) through the various stages in the process and is primarily used by government, manufacturing and construction industries. Although there are various modified waterfall models, the original waterfall model is said to have involved:

  • System and software requirements
  • Analysis
  • Design
  • Coding
  • Testing
  • Operations

V-Shaped Model

The v-shaped model, also known as the verification and validation model, is a sequential software development process in which the steps flow in a v-shape, down in a linear fashion and then bent up after the coding stage. The v-shaped model is primarily used in the medical device industry. Although there are various versions of the v-shaped model, the original version is said to have involved:

  • Requirements
  • System design
  • Architecture design
  • Module design
  • Implementation/coding
  • Unit testing
  • Integration testing
  • System testing
  • Acceptance testing

Iterative Model

The iterative model is a circular development model based on the concept of incremental development, which means that development initially focuses on an initial simplified version (MVP feature sets) and then progressively becomes more complex as the feature sets expand until the entire product is developed. This process is called iterative incremental development because it is said to be completed through repeated cycles (iterative) of small portions (incremental) and includes the following steps:

  • Initial planning
  • Planning
  • Requirements
  • Analysis and design
  • Implementation
  • Testing
  • Evaluation
  • Everything again..
  • Everything again..
  • Everything again until it’s ready…
  • Deployment

Spiral Model

The spiral model, also known as the meta model, subsumes other SDLC models including the waterfall and iterative models, and is known to be risk averse because of the way the spiral model handles risks after projects have begun. In the spiral model, software development is completed by repeatedly passing through phases of iteration called spirals, which are:

  • Plan objectives or identify alternative solutions
  • Perform risk analysis
  • Develop and test next level of product
  • Review, evaluate and plan the next phase

Big Bang Model

The big bang model is an SDLC model that does not follow a specific set of processes or planning and is very high risk because it adopts a just-do-it approach without analysis or clear requirements.

Agile Model

The agile SDLC model is a process in which development is completed in small, quick segments, or increments. Essentially, it is a mix of interactive and incremental approaches focused on being flexible and adaptable. The agile model is one of the most widely used models in the technology industry because it gives teams the flexibility of measuring progress regularly, adapting to changing environments and needs of users, and receiving feedback in real-time by releasing working software and updated feature sets more frequently and getting feedback from the market. The agile model works something like:

  • Brainstorm and requirements analysis
  • Design documentation and prototyping
  • Development iterations, demo and feedback
  • Quality assurance, testing, iterations, demo and feedback
  • Development, production and technical support
  • Repeat

OR instead…

  • Plan
  • Design
  • Develop
  • Test
  • Release
  • Feedback
  • Repeat

Conclusion 

In short, the software development life cycle is a structured process which can vary from company to company aiming to deliver the best quality products. It can be shaped or adjusted to the needs of the customer or according to the needs of the project that is being worked on. 

It is a foundational model used to arrange a framework and equip every team member engaged in technical and non-technical activities. Other benefits of the software lifecycle processes are that it provides visibility for all those involved in the project, eliminates risks like going over budget and provides a realistic outline of deliverables. Find out more about our embedded software development services here

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