SDLC-Software Development Life Cycle

Phases or stages of a project from inception through completion and delivery of the final product and maintenance too.

Software Development Stages

RequirementAnalysisDesignCodingTestingDeploymentMaintenance

Requirement PhaseBusiness Requirement – Represent high level objectives of the organization or customer requesting the system or product.General questions – who is going to use the system, how will they use the system, what data should be input into the system, what data should be output by the system.User Requirement – Describe the tasks the user must be able to accomplish with the product.Ex:- Enter user id in the Agent field, Enter the password in the password field, Click Ok.Functional Requirements – Define the application’s software functionality to enable user to accomplish their tasks, thereby satisfying the business requirements.Documented in a Software Requirement Specification (SRS)Ex – Allow access to authorized user ids and passwords, Deny access to invalid user ids and passwords.

Analysis PhaseThe process of identifying requirements, current problems, opportunities for improvement, timelines and Resources costs.Figuring out what your program should do in the best way possibleInvestigate the need for possible software automation in the given system.

Design PhaseDetermine the set of instructions that will lead to a solution that meets the customers requirements.Architecture, including hardware and software, software design are all part of the deliverables of a design phase.High Level Design Specification – List of modules and a brief description of each, Brief functionality of each module, interface relationship among modules, dependencies between modules, database tables identified with key elements.Low Level Design Specification – Detailed functional logic of the module, all interface details, completed input and output format of a module.

Coding PhaseThe specification from the detailed design phase are converted into programs.Code is produced from the deliverables of the design phase during implementation, and this is the longest phase of the software development phase.Design must be translated into a machine-readable form taking input as SRS. (One by team of developers, Reviews after every 500 lines of code (code inspection, code walkthrough)).

Testing PhaseFinding the hidden defects in developed Product.During testing, the implementation is tested against the requirements to make sure that the product is actually solving the needs addressed and gathering during the requirements phase.Unit, Integration, system and acceptance tests are done during this phase. Unit tests act on a specific component of the system, while system tests act on the system as a whole.

Deployment and Close PhaseDeploying the product at client side.Installation and setup of software application at the customer site

Maintenance PhaseMaintaining the software application.Provide supportIntegrate new features requested by customersSoftware is maintained due to changes (unexpected values into the system)

SDLC Models

Waterfall ModelIncremental/Overlapping ModelPrototyping ModelSpiral ModelV – ModelRapid Application Model