Editing Systems development life cycle (section)

=== Waterfall ===
The oldest and best known is the [[waterfall model]], which uses a linear sequence of steps.<ref name="EverettSoftware07" /> Waterfall has different varieties. One variety is as follows:<ref name="US DJ03" /><ref name="EverettSoftware07" /><ref>{{cite web |url=http://www.computerworld.com/s/article/71151/System_Development_Life_Cycle |title=QuickStudy: System Development Life Cycle |first=Russell |last=Kay |date=May 14, 2002 |work=ComputerWorld}}</ref><ref name="TaylorIntro08">{{cite book |url=https://books.google.com/books?id=gqpZDNc5_Y4C&pg=SA12-PA6 |title=Introduction to Logistics Engineering |author=Taylor, G.D. |publisher=CRC Press |pages=12.6–12.18 |year=2008 |isbn=9781420088571}}</ref>

====  Preliminary analysis  ====
Conduct with a preliminary analysis, consider alternative solutions, estimate costs and benefits, and submit a preliminary plan with recommendations.
:* Conduct preliminary analysis: Identify the organization's objectives and define the nature and scope of the project. Ensure that the project fits with the objectives.
:* Consider alternative solutions: Alternatives may come from interviewing employees, clients, suppliers, and consultants, as well as competitive analysis.
:* Cost-benefit analysis: Analyze the costs and benefits of the project.

====  Systems analysis, requirements definition  ====
Decompose project goals{{Clarify|reason=Where did the goals come from?|date=January 2023}} into defined functions and operations. This involves gathering and interpreting facts, diagnosing problems, and recommending changes. Analyze end-user information needs and resolve inconsistencies and incompleteness:<ref>{{cite book|title=Information Systems Control and Audit |url=https://resource.cdn.icai.org/48513bos30870-sm-cp5.pdf |publisher=Institute of Chartered Accountants of India|chapter=Chapter 5|page=5.28|date=August 2013}}</ref>
:* Collect facts: Obtain end-user requirements by document review, client interviews, observation, and questionnaires.
:* Scrutinize existing system(s): Identify pros and cons.
:* Analyze the proposed system: Find solutions to issues and prepare specifications, incorporating appropriate user proposals.

====  Systems design  ====
At this step, desired features and operations are detailed, including screen layouts, [[business rule]]s, [[process flow diagram|process diagram]]s, [[pseudocode]], and other deliverables.

==== Development ====
Write the code.

==== Integration and testing ====
Assemble the modules in a testing environment. Check for errors, bugs, and interoperability.

==== Acceptance, installation, deployment ====
Put the system into production. This may involve training users, deploying hardware, and loading information from the prior system.

==== Maintenance ====
Monitor the system to assess its ongoing fitness. Make modest changes and fixes as needed. To maintain the quality of the system. Continual monitoring and updates ensure the system remains effective and high-quality.<ref>{{cite web |last1=Shah |first1=Kazim |title=The Maintenance Phase Of Software Development Life Cycle |url=https://www.primetechnologiesglobal.com/blog/maintenance-phase-of-software-development-life-cycle |website=primetechnologiesglobal |publisher=kazim shah |access-date=12 May 2024}}</ref>

==== Evaluation ====
The system and the process are reviewed. Relevant questions include whether the newly implemented system meets requirements and achieves project goals, whether the system is usable, reliable/available, properly scaled and fault-tolerant. Process checks include review of timelines and expenses, as well as user acceptance.

==== Disposal ====
At end of life, plans are developed for discontinuing the system and transitioning to its replacement. Related information and infrastructure must be repurposed, archived, discarded, or destroyed, while appropriately protecting security.<ref>{{cite web |last=Radack |first=S. |date=n.d. |title=The system development life cycle (SDLC) |url=https://csrc.nist.rip/publications/nistbul/april2009_system-development-life-cycle.pdf |publisher=National Institute of Standards and Technology}}</ref>

In the following diagram, these stages are divided into ten steps, from definition to creation and modification of IT work products: