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The **Systems Development Life Cycle (SDLC)**, or //Software Development Life Cycle// in [|systems engineering], [|information systems] and [|software engineering], is a process of creating or altering information systems, and the models and [|methodologies] that people use to develop these systems. In software engineering the SDLC concept underpins many kinds of [|software development methodologies]. These methodologies form the framework for planning and controlling the creation of an information system

Systems Development Life Cycle (SDLC) is a process used by a [|systems analyst] to develop an [|information system], including [|requirements], [|validation], [|training], and user (stakeholder) ownership. Any SDLC should result in a high quality system that meets or exceeds customer expectations, reaches completion within time and cost estimates, works effectiv ely and efficiently in the current and planned [|Information Technology] [|infrastructure], and is inexpensive to maintain and cost-effective to enhance Computer systems are complex and often (especially with the recent rise of [|Service-Oriented Architecture]) link multiple traditional systems potentially supplied by different software vendors. To manage this level of complexity, a number of SDLC models or methodologies have been created, such as "[|waterfall]"; "[|spiral]"; "[|Agile software development]"; "[|rapid prototyping]"; "[|incremental]"; and "synchronize and stabilize".[|[][|3]SDLC models can be described along a spectrum of agile to iterative to sequential. [|Agile methodologies], such as [|XP] and [|Scrum], focus on lightweight processes which allow for rapid changes along the development cycle. [|Iterative] methodologies, such as [|Rational Unified Process] and [|Dynamic Systems Development Method], focus on limited project scope and expanding or improving products by multiple iterations. Sequential or big-design-up-front (BDUF) models, such as [|Waterfall], focus on complete and correct planning to guide large projects and risks to successful and predictable results[//[|citation needed]//]. Other models, such as [|Anamorphic Development], tend to focus on a form of development that is guided by project scope and adaptive iterations of feature development. In [|project management] a project can be defined both with a [|project life cycle] (PLC) and an SDLC, during which slightly different activities occur. According to Taylor (2004) "the project life cycle encompasses all the activities of the [|project], while the systems development life cycle focuses on realizing the product [|requirements]".[|[][|4] [[image:saleeh/800px-CPT-SystemLifeSycle_svg.png width="440" height="269"]] The System Development Life Cycle framework provides a sequence of activities for system designers and developers to follow. It consists of a set of steps or phases in which each phase of the SDLC uses the results of the previous one. A Systems Development Life Cycle (SDLC) adheres to important phases that are essential for developers, such as [|planning], [|analysis], [|design], and [|implementation], and are explained in the section below. A number of system development life cycle (SDLC) models have been created: waterfall, fountain, spiral, build and fix, rapid prototyping, incremental, and synchronize and stabilize. The oldest of these, and the best known, is the [|waterfall model]: a sequence of stages in which the output of each stage becomes the input for the next. These stages can be characterized and divided up in different ways, including the following[ **Project planning, feasibility study**: Establishes a high-level view of the intended project and determines its goals. > = System analysis = > The goal of [|system analysis] is to determine where the problem is in an attempt to fix the system. This step involves [|breaking down] the system in different pieces to analyze the situation, analyzing project goals, breaking down what needs to be created and attempting to engage users so that definite requirements can be defined. > [|Requirements analysis] sometimes requires individuals/teams from client as well as service provider sides to get detailed and accurate requirements; often there has to be a lot of communication to and from to understand these requirements. Requirement gathering is the most crucial aspect as many times communication gaps arise in this phase and this leads to validation errors and bugs in the software program. > > = Design = > In [|systems design] the design functions and operations are described in detail, including screen layouts, business rules, process diagrams and other documentation. The output of this stage will describe the new system as a collection of modules or subsystems. > The design stage takes as its initial input the requirements identified in the approved requirements document. For each requirement, a set of one or more design elements will be produced as a result of interviews, workshops, and/or prototype efforts. > Design elements describe the desired software features in detail, and generally include functional hierarchy diagrams, screen layout diagrams, tables of business rules, business process diagrams, pseudocode, and a complete entity-relationship diagram with a full data dictionary. These design elements are intended to describe the software in sufficient detail that skilled programmers may develop the software with minimal additional input design. > > = Testing = > The code is tested at various levels in [|software testing]. Unit, system and user acceptance testings are often performed. This is a grey area as many different opinions exist as to what the stages of testing are and how much if any iteration occurs. Iteration is not generally part of the waterfall model, but usually some occur at this stage. In the testing the whole system is test one by one > Following are the types of testing: > > = Operations and maintenance = > The [|deployment] of the system includes changes and enhancements before the decommissioning or sunset of the system. [|Maintaining] the system is an important aspect of SDLC. As key personnel change positions in the organization, new changes will be implemented, which will require system updates.[[image:saleeh/SDLC_Phases_Related_to_Management_Controls.jpg width="473" height="238"]] > The Systems Development Life Cycle (SDLC) phases serve as a programmatic guide to project activity and provide a flexible but consistent way to conduct projects to a depth matching the scope of the project. Each of the SDLC phase objectives are described in this section with key deliverables, a description of recommended tasks, and a summary of related control objectives for effective management. It is critical for the project manager to establish and monitor control objectives during each SDLC phase while executing projects. Control objectives help to provide a clear statement of the desired result or purpose and should be used throughout the entire SDLC process. Control objectives can be grouped into major categories (Domains), and relate to the SDLC phases as shown in the figureTo manage and control any SDLC initiative, each project will be required to establish some degree of a [|Work Breakdown Structure] (WBS) to capture and schedule the work necessary to complete the project. The WBS and all programmatic material should be kept in the “Project Description” section of the project notebook. The WBS format is mostly left to the project manager to establish in a way that best describes the project work. There are some key areas that must be defined in the WBS as part of the SDLC policy. The following diagram describes three key areas that will be addressed in the WBS in a manner established by the project manager.[|[][|8]
 * **Systems analysis, requirements definition**: Defines project goals into defined functions and operation of the intended application. Analyzes end-user information needs.
 * **Systems design**: Describes desired features and operations in detail, including screen layouts, business rules, process diagrams, pseudocode and other documentation.
 * **Implementation**: The real code is written here.
 * **Integration and testing**: Brings all the pieces together into a special testing environment, then checks for errors, bugs and interoperability.
 * **Acceptance, installation, deployment**: The final stage of initial development, where the software is put into production and runs actual business.
 * **Maintenance**: What happens during the rest of the software's life: changes, correction, additions, moves to a different computing platform and more. This, the least glamorous and perhaps most important step of all, goes on seemingly forever.
 * //Defect testing// the failed scenarios, including [|defect tracking]
 * [|Path testing]
 * [|Data set testing]
 * [|Unit testing]
 * [|System testing]
 * [|Integration testing]
 * [|Black-box testing]
 * [|White-box testing]
 * [|Regression testing]
 * [|Automation testing]
 * [|User acceptance testing]
 * =Performance testing=