systems development life cycle for other uses see sdlc disambiguation model of the systems development life cycle highlighting the maintenance phase the systems development life cycle sdlc also referred to as the application development lifecycle 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 there are usually six stages in this cycle analysis design development and testing implementation documentation and evaluation overview a systems development life cycle is composed of a number of clearly defined and distinct work phases which are used by systems engineers and systems developers to plan for design build test and deliver information systems like anything that is manufactured on an assembly line an sdlc aims to produce highquality systems that meet or exceed customer expectations based on customer requirements by delivering systems which move through each clearly defined phase within scheduled time frames and cost estimates computer systems are complex and often especially with the recent rise of serviceoriented 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 sdlc can be described along a spectrum of agile to iterative to sequential methodologies agile methodologies such as xp and scrum focus on lightweight processes which allow for rapid changes without necessarily following the pattern of sdlc approach 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 bigdesignupfront bduf models such as waterfall focus on complete and correct planning to guide large projects and risks to successful and predictable results 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 sdlc is used during the development of an it project it describes the different stages involved in the project from the drawing board through the completion of the project the sdlc is not a methodology per se but rather a description of the phases in the life cycle of a software application these phases broadly speaking are investigation analysis design build test implement and maintenance and support all software development methodologies such as the more commonly known waterfall and scrum methodologies follow the sdlc phases but the method of doing that varies vastly between methodologies in the scrum methodology for example one could say a single user story goes through all the phases of the sdlc within a single twoweek sprint contrast this to the waterfall methodology as another example where every business requirement recorded in the analysis phase of the sdlc in a document called the business requirements specification is translated into featurefunctional descriptions recorded in the design phase in a document called the functional specification which are then all built in one go as a collection of solution features typically over a period of three to nine months or more these methodologies are obviously quite different approaches yet they both contain the sdlc phases in which a requirement is born then travels through the life cycle phases ending in the final phase of maintenance and support afterwhich typically the whole life cycle starts again for a subsequent version of the software application history and details the product life cycle describes the process for building information systems in a very deliberate structured and methodical way reiterating each stage of the products life the systems development life cycle according to elliott strachan radford 2004 originated in the 1960s to develop large scale functional business systems in an age of large scale business conglomerates information systems activities revolved around heavy data processing and number crunching routines several systems development frameworks have been partly based on sdlc such as the structured systems analysis and design method ssadm produced for the uk government office of government commerce in the 1980s ever since according to elliott 2004 the traditional life cycle approaches to systems development have been increasingly replaced with alternative approaches and frameworks which attempted to overcome some of the inherent deficiencies of the traditional sdlc phases 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 the sdlc adheres to important phases that are essential for developerssuch as planning analysis design and implementationand are explained in the section below this includes evaluation of the currently used system information gathering feasibility studies and request approval a number of sdlc models have been created including waterfall fountain spiral build and fix rapid prototyping incremental synchronize and stabilize preliminary analysis begin with a preliminary analysis propose alternative solutions describe costs and benefits and submit a preliminary plan with recommendations conduct the preliminary analysis discover the organizations objectives and the nature and scope of the problem under study even if a problem refers only to a small segment of the organization itself find out what the objectives of the organization itself are then see how the problem being studied fits in with them propose alternative solutions after digging into the organizations objectives and specific problems several solutions may have been discovered however alternate proposals may still come from interviewing employees clients suppliers andor consultants insight may also be gained by researching what competitors are doing cost benefit analysis analyze and describe the costs and benefits of implementing the proposed changes in the end the ultimate decision on whether to leave the system as is improve it or develop a new system will be guided by this and the rest of the preliminary analysis data systems analysis requirements definition define project goals into defined functions and operations of the intended application this involves the process of gathering and interpreting facts diagnosing problems and recommending improvements to the system project goals will be further aided by analysis of enduser information needs and the removal of any inconsistencies and incompleteness in these requirements a series of steps followed by the developer include collection of facts obtain end user requirements through documentation client interviews observation and questionnaires scrutiny of the existing system identify pros and cons of the current system inplace so as to carry forward the pros and avoid the cons in the new system analysis of the proposed system find solutions to the shortcomings described in step two and prepare the specifications using any specific user proposals systems design at this step desired features and operations are described in detail including screen layouts business rules process diagrams pseudocode and other documentation development the real code is written here integration and testing all the pieces are brought together into a special testing environment then checked for errors bugs and interoperability acceptance installation deployment this is the final stage of initial development where the software is put into production and runs actual business maintenance during the maintenance stage of the sdlc the system is assessedevaluated to ensure it does not become obsolete this is also where changes are made to initial software evaluation some companies do not view this as an official stage of the sdlc while others consider it to be an extension of the maintenance stage and may be referred to in some circles as postimplementation review this is where the system that was developed as well as the entire process is evaluated some of the questions that need to be answered include if the newly implemented system meets the initial business requirements and objectives if the system is reliable and faulttolerant and if it functions according to the approved functional requirements in addition to evaluating the software that was released it is important to assess the effectiveness of the development process if there are any aspects of the entire process or certain stages that management is not satisfied with this is the time to improve disposal in this phase plans are developed for discontinuing the use of system information hardware and software and making the transition to a new system the purpose here is to properly move archive discard or destroy information hardware and software that is being replaced in a manner that prevents any possibility of unauthorized disclosure of sensitive data the disposal activities ensure proper migration to a new system particular emphasis is given to proper preservation and archiving of data processed by the previous system all of this should be done in accordance with the organizations security requirements in the following diagram these stages of the systems development life cycle are divided in ten steps from definition to creation and modification of it work products a tenphase version of the systems development life cycle not every project will require that the phases be sequentially executed however the phases are interdependent depending upon the size and complexity of the project phases may be combined or may overlap system investigation first the it system proposal is investigated during this step consider all current priorities that would be affected and how they should be handled before any system planning is done a feasibility study should be conducted to determine if creating a new or improved system is a viable solution this will help to determine the costs benefits resource requirements and specific user needs required for completion the development process can only continue once management approves of the recommendations from the feasibility study the following represent different components of the feasibility study operational feasibility economic feasibility technical feasibility human factors feasibility legalpolitical feasibility analysis the goal of 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 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 andor prototype efforts design elements describe the desired system features in detail and they generally include functional hierarchy diagrams screen layout diagrams tables of business rules business process diagrams pseudocode and a complete entityrelationship diagram with a full data dictionary these design elements are intended to describe the system in sufficient detail such that skilled developers and engineers may develop and deliver the system with minimal additional input design environments environments are controlled areas where systems developers can build distribute install configure test and execute systems that move through the sdlc each environment is aligned with different areas of the sdlc and is intended to have specific purposes examples of such environments include the development environment where developers can work independently of each other before trying to merge their work with the work of others common build environment where merged work can be built together as a combined system systems integration testing environment where basic testing of a systems integration points to other upstream or downstream systems can be tested user acceptance testing environment where business stakeholders can test against their original business requirements and production environment where systems finally get deployed for final use by their intended end users 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 the means to rectify defects and validate fixes prior to deployment is incorporated into this phase the following are types of testing that may be relevant depending on the type of system under development defect testing the failed scenarios including defect tracking path testing data set testing unit testing system testing integration testing blackbox testing whitebox testing regression testing automation testing user acceptance testing software performance testing training and transition once a system has been stabilized through adequate testing the sdlc ensures that proper training on the system is performed or documented before transitioning the system to its support staff and end users training usually covers operational training for those people who will be responsible for supporting the system as well as training for those end users who will be using the system after its delivery to a production operating environment after training has been successfully completed systems engineers and developers transition the system to its final production environment where it is intended to be used by its end users and supported by its support and operations staff 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 there are two approaches to system development the traditional approach structured and object oriented information engineering includes the traditional system approach which is also called the structured analysis and design technique the object oriented approach views information system as a collection of objects that are integrated with each other to make a full and complete information system evaluation the final phase of the sdlc is to measure the effectiveness of the system and evaluate potential enhancements systems analysis and design the systems analysis and design sad is the process of developing information systems is that effectively use hardware software data processes and people to support the companys businesses objectives system analysis and design can be considered the metadevelopment activity which serves to set the stage and bound the problem sad can be leveraged to set the correct balance among competing highlevel requirements in the functional and nonfunctional analysis domains system analysis and design interacts strongly with distributed enterprise architecture enterprise it architecture and business architecture and relies heavily on concepts such as partitioning interfaces personae and roles and deploymentoperational modeling to arrive at a highlevel system description this high level description is then further broken down into the components and modules which can be analyzed designed and constructed separately and integrated to accomplish the business goal sdlc and sad are cornerstones of full life cycle product and system planning objectoriented analysis objectoriented analysis ooa is the process of analyzing a task also known as a problem domain to develop a conceptual model that can then be used to complete the task a typical ooa model would describe computer software that could be used to satisfy a set of customerdefined requirements during the analysis phase of problemsolving a programmer might consider a written requirements statement a formal vision document or interviews with stakeholders or other interested parties the task to be addressed might be divided into several subtasks or domains each representing a different business technological or other areas of interest each subtask would be analyzed separately implementation constraints eg concurrency distribution persistence or how the system is to be built are not considered during the analysis phase rather they are addressed during objectoriented design ood the conceptual model that results from ooa will typically consist of a set of use cases one or more uml class diagrams and a number of interaction diagrams it may also include some kind of user interface mockup the input for objectoriented design is provided by the output of objectoriented analysis realize that an output artifact does not need to be completely developed to serve as input of objectoriented design analysis and design may occur in parallel and in practice the results of one activity can feed the other in a short feedback cycle through an iterative process both analysis and design can be performed incrementally and the artifacts can be continuously grown instead of completely developed in one shot some typical but common to all types of design analysis input artifacts for objectoriented conceptual model conceptual model is the result of objectoriented analysis it captures concepts in the problem domain the conceptual model is explicitly chosen to be independent of implementation details such as concurrency or data storage use case use case is a description of sequences of events that taken together lead to a system doing something useful each use case provides one or more scenarios that convey how the system should interact with the users called actors to achieve a specific business goal or function use case actors may be end users or other systems in many circumstances use cases are further elaborated into use case diagrams use case diagrams are used to identify the actor users or other systems and the processes they perform system sequence diagram system sequence diagram ssd is a picture that shows for a particular scenario of a use case the events that external actors generate their order and possible intersystem events user interface documentations if applicable document that shows and describes the look and feel of the end products user interface it is not mandatory to have this but it helps to visualize the endproduct and therefore helps the designer relational data model if applicable a data model is an abstract model that describes how data is represented and used if an object database is not used the relational data model should usually be created before the design since the strategy chosen for objectrelational mapping is an output of the oo design process however it is possible to develop the relational data model and the objectoriented design artifacts in parallel and the growth of an artifact can stimulate the refinement of other artifacts life cycle management and control spiu phases related to management controls the 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 figure to 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 the diagram shows coverage spans numerous phases of the sdlc but the associated mcd has a subset of primary mappings to the sdlc phases for example analysis and design is primarily performed as part of the acquisition and implementation domain and system build and prototype is primarily performed as part of delivery and support work breakdown structured organization work breakdown structure the upper section of the work breakdown structure wbs should identify the major phases and milestones of the project in a summary fashion in addition the upper section should provide an overview of the full scope and timeline of the project and will be part of the initial project description effort leading to project approval the middle section of the wbs is based on the seven systems development life cycle phases as a guide for wbs task development the wbs elements should consist of milestones and tasks as opposed to activities and have a definitive period usually two weeks or more each task must have a measurable output ex document decision or analysis a wbs task may rely on one or more activities eg software engineering systems engineering and may require close coordination with other tasks either internal or external to the project any part of the project needing support from contractors should have a statement of work sow written to include the appropriate tasks from the sdlc phases the development of a sow does not occur during a specific phase of sdlc but is developed to include the work from the sdlc process that may be conducted by external resources such as contractors baselines baselines are an important part of the systems development life cycle these baselines are established after four of the five phases of the sdlc and are critical to the iterative nature of the model each baseline is considered as a milestone in the sdlc functional baseline established after the conceptual design phase allocated baseline established after the preliminary design phase product baseline established after the detail design and development phase updated product baseline established after the production construction phase complementary methodologies complementary software development methods to systems development life cycle are software prototyping joint applications development jad rapid application development rad extreme programming xp opensource development enduser development objectoriented programming comparison of methodology approaches post anderson 2006 sdlc rad open source objects jad prototyping end user control formal mis weak standards joint user user time frame long short medium any medium short short users many few few varies few one or two one mis staff many few hundreds split few one or two none transactiondss transaction both both both dss dss dss interface minimal minimal weak windows crucial crucial crucial documentation and training vital limited internal in objects limited weak none integrity and security vital vital unknown in objects limited weak weak reusability limited some maybe vital limited weak none strengths and weaknesses few people in the modern computing world would use a strict waterfall model for their sdlc as many modern methodologies have superseded this thinking some will argue that the sdlc no longer applies to models like agile computing but it is still a term widely in use in technology circles the sdlc practice has advantages in traditional models of systems development that lends itself more to a structured environment the disadvantages to using the sdlc methodology is when there is need for iterative development or ie web development or ecommerce where stakeholders need to review on a regular basis the software being designed a comparison of the strengths and weaknesses of sdlc strength and weaknesses of sdlc strengths weaknesses control increased development time monitor large projects increased development cost detailed steps systems must be defined up front evaluate costs and completion targets rigidity documentation hard to estimate costs project overruns well defined user input user input is sometimes limited ease of maintenance little parallelism development and design standards automation of documentation and standards is limited tolerates changes in mis of staffing does not tolerate changes in requirements projects canned early on the result in little or no value an alternative to the sdlc is rapid application development which combines prototyping joint application development and implementation of case tools the advantages of rad are speed reduced development cost and active user involvement in the development process system lifecycle the system lifecycle in systems engineering is a view of a system or proposed system that addresses all phases of its existence to include system conception design and development production andor construction distribution operation maintenance and support retirement phaseout and disposal conceptual design the conceptual design stage is the stage where an identified need is examined requirements for potential solutions are defined potential solutions are evaluated and a system specification is developed the system specification represents the technical requirements that will provide overall guidance for system design because this document determines all future development the stage cannot be completed until a conceptual design review has determined that the system specification properly addresses the motivating need key steps within the conceptual design stage include need identification feasibility analysis system requirements analysis system specification conceptual design review preliminary system design during this stage of the system lifecycle subsystems that perform the desired system functions are designed and specified in compliance with the system specification interfaces between subsystems are defined as well as overall test and evaluation requirements at the completion of this stage a development specification is produced that is sufficient to perform detailed design and development key steps within the preliminary design stage include functional analysis requirements allocation detailed tradeoff studies synthesis of system options preliminary design of engineering models development specification preliminary design review for example as the system analyst of viti bank you have been tasked to examine the current information system viti bank is a fast growing bank in fiji customers in remote rural areas are finding difficulty to access the bank services it takes them days or even weeks to travel to a location to access the bank services with the vision of meeting the customers needs the bank has requested your services to examine the current system and to come up with solutions or recommendations of how the current system can be provided to meet its needs detail design and development this stage includes the development of detailed designs that brings initial design work into a completed with form of specifications this work includes the specification of interfaces between the system and its intended environment and a comprehensive evaluation of the systems logistical maintenance and support requirements the detail design and development is responsible for producing the product process and material specifications and may result in substantial changes to the development specification key steps within the detail design and development stage include detailed design detailed synthesis development of engineering and prototype models revision of development specification product process and material specification critical design review production and construction during the production andor construction stage the product is built or assembled in accordance with the requirements specified in the product process and material specifications and is deployed and tested within the operational target environment system assessments are conducted in order to correct deficiencies and adapt the system for continued improvement key steps within the product construction stage include production andor construction of system components acceptance testing system distribution and operation operational testing and evaluation system assessment utilization and support once fully deployed the system is used for its intended operational role and maintained within its operational environment key steps within the utilization and support stage include system operation in the user environment change management system modifications for improvement system assessment phaseout and disposal effectiveness and efficiency of the system must be continuously evaluated to determine when the product has met its maximum effective lifecycle considerations include continued existence of operational need matching between operational requirements and system performance feasibility of system phaseout versus maintenance and availability of alternative systems application lifecycle management decision cycle ipo model software development methodologies cummings haag 2006 management information systems for the information age toronto mcgrawhill ryerson beynondavies p 2009 business information systems palgrave basingstoke isbn9780230203686 computer world 2002 retrieved on june 22 2006 from the world wide web management information systems 2005 retrieved on june 22 2006 from the world wide web this article is based on material taken from the free online dictionary of computing prior to 1 november 2008 and incorporated under the relicensing terms of the gfdl version 13 or later wikimedia commons has media related to systems development life cycle the agile system development lifecycle pension benefit guaranty corporation information technology solutions lifecycle methodology fsa life cycle framework hhs enterprise performance life cycle framework the open systems development life cycle system development life cycle evolution modeling zero deviation life cycle integrated defense atl life cycle management chart the us dod form of this concept vtesoftware engineeringfields computer programming requirements engineering software deployment software design software maintenance software testing systems analysis formal methods concepts data modeling enterprise architecture functional specification modeling language orthogonality programming paradigm software software archaeology software architecture software configuration management software development methodology software development process software quality software quality assurance software verification and validation structured analysis orientations agile aspectoriented object orientation ontology service orientation sdlc modelsdevelopmental agile eup executable uml incremental model iterative model prototype model rad up scrum spiral model vmodel waterfall model xp other spice cmmi data model er model function model information model metamodeling object model systems model view model languages idef uml usl sysml softwareengineers victor basili kent beck grady booch fred brooks barry boehm peter chen danese cooper ward cunningham tom demarco edsger w dijkstra delores m etter martin fowler adele goldstine margaret hamilton c a r hoare lois haibt mary jean harrold grace hopper watts humphrey michael a jackson ivar jacobson alan kay nancy leveson stephen j mellor bertrand meyer david parnas trygve reenskaug winston w royce james rumbaugh mary shaw peri tarr elaine weyuker niklaus wirth edward yourdon related fields computer science computer engineering project management risk management systems engineering category commons vtesystems engineeringsubfields aerospace engineering biological systems engineering configuration management earth systems engineering and management electrical engineering enterprise systems engineering performance engineering reliability engineering safety engineering processes requirements engineering functional specification system integration verification and validation design review concepts business process system system lifecycle vmodel systems development life cycle tools decisionmaking function modelling idef optimization quality function deployment system dynamics systems modeling language systems analysis systems modeling work breakdown structure people james s albus ruzena bajcsy benjamin s blanchard wernher von braun kathleen carley harold chestnut wolt fabrycky barbara grosz arthur david hall iii derek hitchins robert e machol radhika nagpal simon ramo joseph francis shea katia sycara manuela m veloso john n warfield related fields control engineering computer engineering industrial engineering operations research project management quality management risk management software engineering category 