An important methodology in the creation of software and applications is the software development life cycle (SDLC). The software development life cycle is a term used in systems engineering, information systems, and software engineering to describe a process for planning, creating, testing, and deploying an information system.
An important aspect of project management is choosing the right SDLC model, such as Agile, iterative, or spiral methodologies, to ensure successful project execution.
There are many phases involved in the software development life cycle.
What is the Systems Development Life Cycle?
The SDLC is a project management model that outlines the stages necessary to bring a project from its initial idea or conception to deployment and later maintenance. It is an important tool for project managers and system analysts, helping to ensure that projects are completed on time, within budget, and to the required quality standards.
By following the SDLC, project managers can systematically plan, execute, and control the development process, ensuring that all aspects of the project are addressed comprehensively. This structured approach not only enhances the efficiency of the development life cycle but also mitigates risks and ensures that the final product aligns with the business objectives and user needs.
Key Objectives of SDLC
The key objectives of SDLC include improving the quality of software products, reducing development time and cost, enhancing customer satisfaction, and better managing software development projects. SDLC also aims to improve communication among team members, reduce the risk of project failure, and improve the scalability and maintainability of software products.
By following the SDLC process, development teams can ensure that their software products meet the required standards and are delivered on time and within budget. Additionally, the SDLC framework promotes a disciplined approach to software development, encouraging continuous improvement and adaptation to changing project requirements, which is needed for achieving long-term project success.
What are the Phases of the Systems Development Life Cycle (SDLC)?
SDLC Phase 1: Preliminary Analysis
What is the first step of the SDLC? Phase 1 of the systems development life cycle involves a preliminary analysis, an initial phase at the start of a project that determines whether the concept is viable; any proposed alternative solutions; the cost benefit evaluation; and finally the submission of the preliminary plan for recommendations. Before the preliminary analysis is complete, the developer performs feasibility studies to determine whether to fix the existing system or create a new system to replace the old.
The different components of the feasibility study within the system development life cycle include:
- Operational Feasibility – measures how well a proposed system solves the problems, provides the required solutions, takes advantage of the opportunities identified during scope definition, and how the system satisfies the requirements identified in the requirements analysis phase of the system development life cycle.
- Economic Feasibility – determines the positive economic benefits that the system will provide (cost benefit analysis).
- Technical Feasibility – confirms the system will perform and verifies there are no production barriers.
- Human Factors Feasibility – determines whether the system is relevant and can be managed by the end user.
What Is a Cost Benefit Analysis?
A cost benefit analysis (CBA) is a systematic approach to estimating the strengths and weaknesses of alternatives and is used to determine options that provide the best approach to achieve the most benefit within the system development life cycle.
What Are the Phases in a Cost Benefit Analysis?
The first phase is to compile a comprehensive list of all the costs and benefits associated with the system. Costs include direct and indirect costs, intangible costs, opportunity costs and cost of potential risks. Benefits include direct and indirect revenues and intangible benefits. The final step is to quantitatively compare the results of the aggregate costs and benefits to determine if the benefits outweigh the costs.
SDLC Phase 2: Systems Analysis
Phase 2 of the systems development life cycle defines the project goals broken down into defined functions and operation of the application. During this analysis stage, facts are gathered and interpreted, problems are diagnosed, and improvements are recommended. There are several tools that can be used for systems analysis, and they include:
- CASE (Computer Aided Systems/Software Engineering) – organizes and controls the development of software or systems through use of a computer-assisted method. Using CASE allows everyone to share a common view of the project and where it stands at each stage of development.
- Requirements Gathering – provides alternative means to illustrate, explain, and specify exactly what must be delivered to meet business goals.
- Structured Analysis and Design Technique (SADT) – helps people describe and understand systems through a diagrammatic notation. SADT can be used as a functional analysis tool of a given process, using successive levels of detail.
SDLC Phase 3: Systems Design
Phase 3 of the systems development life cycle describes the desired features and operations of the system. The objective of the systems design phase is to transform all requirements into detailed specifications covering all aspects of the system. This includes the creation of a Software Requirement Specification (SRS) that outlines all necessary details and specifications. It should also assess and plan for security risks. Finally, approval to progress to the development phase must be granted to complete the systems design phase.
SDLC Phase 4: Development
Phase 4 of the systems development life cycle is when developers write code for the desired features and operations. The development stage is critical within the SDLC as it involves building applications according to predefined design documents and specifications. Adhering to project specifications during this phase ensures that the coding and system creation processes align with the previously defined requirements and design documents. Programming tools like compilers, interpreters, and language are used for coding. The objective of the development phase within the system development life cycle is to build the system, test and integrate the units into larger components, prepare the technical environment for the system, and finally get approval to progress to the integration and testing phase.
SDLC Phase 5: Integration and Testing
During Phase 5 of the systems development life cycle, the developer tests the system for bugs and errors to make it compliant and accurate. This phase, known as the testing stage, is critical for ensuring that the application’s features align with user expectations and quality standards. The integration and testing phase are usually carried out by a quality assurance professional. There are many different types of testing for a system including:
- Path Testing – ensures that every path through a problem has been executed at least once.
- Data Set Testing – separates the system into a training set and testing set then randomly samples the data to help ensure that the testing and training sets are similar.
- Unit Testing – takes individual units of software source code and tests them to determine whether they are fit for use.
- System Testing – conducts testing on a complete, integrated system to evaluate the system’s compliance with its specified requirements.
- Integration Testing – combines and tests individual software modules as a group.
- Black-Box Testing – examines the functionality of an application without peering into its internal structures or workings.
- White-Box Testing – tests internal structures or workings of an application giving an internal perspective of the system.
- Regression Testing – verifies that software that was previously developed and tested still performs correctly after it was changed or interfaced with other software.
- Automation Testing – automates some repetitive tasks in a formalized testing process already in place.
- User Acceptance Testing (UAT) – also known as beta-testing, tests software in the real world by the intended audience.
- Software Performance Testing – determines how a system performs in terms of responsiveness and stability under a particular workload.
SDLC Phase 6: Acceptance, Installation, and Deployment
Phase 6 of the initial development state of the systems development life cycle puts the software into production and runs as needed. If it performs the tasks correctly and represents the system, the developer moves on to the next phase of maintenance within the system development life cycle.
During deployment of the system there are two processes of changeover:
- Direct Changeover – one-to-one replacement of the old and new systems.
- Parallel Run – both systems are executed simultaneously. If the data is identical between the manual process and the system, then the system is deployed.
SDLC Phase 7: Maintenance
Phase 7 of the systems development life cycle, known as the maintenance stage, assesses and ensures that the system does not become obsolete. The objective of the maintenance phase of the system development life cycle is to manage all changes to the system to support the end user, monitor the system’s performance, perform required security activities, and finally move into the training and documentation for end user support.
SDLC Phase 8: Evaluation
Phase 8 of the systems development life cycle is the post-implementation review. This phase identifies whether the system meets the initial requirements and objectives. This is when the system is evaluated for weaknesses. The objective of the evaluation phase of the systems development life cycle is to deploy the system and train the system end users.
SDLC Phase 9: Disposal
Phase 9 of the systems development life cycle is when plans are initiated to discard system information, hardware, and software in a transition to a new system. It is important to dispose of system information discreetly and securely, as much of the information can be of a personal nature.
SDLC Models
There are several SDLC models, each with its own strengths and weaknesses. These models include the Waterfall model, Agile model, Iterative model, Spiral model, and V-Model. Each model offers a different approach to the software development process, catering to various project needs and complexities. Understanding these models allows project managers and development teams to choose the most appropriate methodology for their specific project, ensuring a more efficient and effective development cycle.
Importance of the Systems Development Life Cycle SDLC
If a problem is identified during any phase of the systems development life cycle, the developer may have to proceed through the life cycle phases once more. All phases of the systems development life cycle need to occur for the success of the app and satisfaction of its users.
Want to Become a Web Application Developer?
Are you interested in the phases of the systems development life cycle SDLC? Want to become a web application developer? The Web Application Design and Development program has a class that teaches the system development Life cycle.
The system development life cycle component of the course introduces aspects of methodology, the unique phases, and the roles that IT professionals and the development team play in the various stages of a project. Students learn how to collect and document requirements, translate them to application design, and trace each project artifact to its original scope.