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SDLC MODEL

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KOMAL DAHERIYA

The document discusses various software development life cycle (SDLC) models. It describes the phases of SDLC as requirements gathering and analysis, design, development, testing, implementation, and maintenance. Several common models are explained in detail, including the waterfall model, prototyping model, incremental model, and spiral model. The waterfall model follows a sequential process from requirements to maintenance, while other iterative models allow for more customer feedback and flexibility to change requirements over multiple iterations of development. Choosing the appropriate model depends on factors like project risks, requirements stability, and need for early delivery of basic functionality.

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SOFTWARE DEVELOPMENT LIFE CYCLE (SDLC) By Komal Daheriya
SDLC MODEL A framework that describes the activities performed at each stage of a software development project.
SDLC PHASES  Requirements Gathering and Analysis  Design  Development  Testing  Implementation  Maintenance
SDLC MODEL To help understand and implement the SDLC phases various SDLC models have been created software development experts, universities, and standards organizations.
REASONS FOR USING SDLC MODEL Provides basis for project planning, estimating& scheduling. Provides framework for standard set of terminologies, activities & deliverables. Provides mechanism for project tracking and control. Increases visibility of project progress to all stakeholders.
ADVANTAGES OF CHOOSING AN APPROPRIATE SDLC Increased development speed. Increased product quality. Improved tracking & control. Decreased project risk. Decreased project management overhead.
COMMON LIFE CYCLE MODELS Waterfall model. Prototype model. Incremental Model. Spiral model.
WATERFALL MODEL Requirement Design Implementation Test Maintenance  Requirement :- Defines needed information, function, behavior performance & interface.  Design :- Data structures, Software architecture, interface representation, algorithm details.  Implementation :- Source code, data base, user documentation, testing.
WATERFALL MODEL Oldest and most well-known SDLC model. Follows a sequential step-by-step process from requirements analysis to maintenance. Systems that have well-defined and understood requirements are a good fit for the Waterfall Model. The waterfall model is also called is linear- sequentional model or classic life cycle model.
BENEFITS OF WATERFALL MODEL Easy to understand, easy to use. Provides structure to inexperienced staff. Sets requirements stability. Good for management control (plan, staff, track)
DRAWBACKS OF WATERFALL MODEL  All requirements must be fully specified upfront. Deliverables created for each phase are considered frozen – inhibits flexibility .  Can give a false impression of progress.  Little opportunity for customer to preview the system (until it may be too late).  The customer can see the working model of the project at the end.
WHEN TO CHOOSE IT Requirements are very well known. Product definition is stable. Technology is understood. New version of an existing product Porting an existing product to a new platform.
PROTOTYPING MODEL Requirement gathering Quick Design Building Prototype Engineering Product Refining Prototype Customer Evaluation Start Stop Prototyping Model
PROTOTYPING MODEL  Prototype is a working model of software with some limited functionality.  Prototype does not always hold the exact logic used in the actual software application.  Prototyping is used to allow the users evaluate developer proposals and try them out before implementation.  It helps get valuable feedback from the customer and helps software designers.
BENEFITS OF PROTOTYPE MODEL  Increased user involvement in the product even before its implementation.  Quicker user feedback is available leading to better solutions.  Missing functionality can be identified easily.  Confusing or difficult functions can be identified.  Reduces time and cost as the defects can be detected much earlier
DRAWBACK OF PROTOTYPE MODEL  Risk of insufficient requirement analysis owing to too much dependency on the prototype.  Users may get confused in the prototypes and actual systems.  The effort invested in building prototypes may be too much if it is not monitored properly.  The first version may have some compromises.  Some time developer may make implementation compromises to get prototype working quickly.
WHEN TO CHOOSE IT  Software application that are relatively easy to prototype almost always involve human- machine interaction (HCI) the prototyping model is suggested.  A general objective of software is defined but not detailed input, processing or output requirements.  When the developer is unsure of the efficiency of an algorithm or the adaptability of an operating system then prototype serves as a better choice.
INCREMENTAL MODEL Requirem ent Analysis Design Software Product Increment 1 Coding Requirem ent Analysis Design Coding Software Product Increment 2 Requirem ent Analysis Design Coding Software Product Increment n Iteration1 Iteration2 …… Iterationn Incremental Model
INCREMENTAL MODEL  The incremental model has some phases that are in waterfall model. But it is iterative in nature.  The first increment in this model is generally a core product.  Each increment builds the product and submits it to the customer for any suggested modifications.  The next increment implements on the customer’s suggestions and additional requirement in the previous increment.
BENEFITS OF INCREMENTAL MODEL  The incremental model can be adopted when there are less number of people involved in the project.  Customers gets important functionality early.  Lowers initial delivery cost.  Each release is a product increment, so that the customer will have a working product at hand all the time.  Requirements changes can be easily accommodated.
DRAWBACK OF INCREMENTAL MODEL  Requires effective planning of iterations.  Problems may arise pertaining to system architecture because not all requirements are gathered up front for the entire software life cycle.  Requires early definition of a complete and fully functional system to allow the definition of increments.
WHEN TO CHOOSE IT There is a need to get the basic functionality delivered fast.  A new technology is being used. Resource with needed skill set are not available. The domain is new to the team.
SPIRAL MODEL
SPIRAL MODEL  The spiral model is similar to the incremental model , with more emphasis placed on risk analysis.  Each loop in a spiral represents a development phase.  Each loop has four sections or quadrants.  The spiral model is dived in to a number of framework activities. The frame work activities are denoted by task regions.
BENEFITS OF SPIRAL MODEL  High amount of risk analysis hence, avoidance of risk is enhanced.  Strong approval & documentation control.  Changing requirements can be accommodated.  Good for large and mission-critical projects.  Software is produced early in the software life cycle.
DRAWBACK OF SPIRAL MODEL  Can be a costly model to use.  Management is more complex.  Not suitable for small or low risk projects and could be expensive for small projects.  Process is complex.  Spiral may go on indefinitely.  Large number of intermediate stages requires excessive documentation.
WHEN TO CHOOSE IT  When costs and risk evaluation is important  For medium to high-risk projects  Long-term project commitment unwise because of potential changes to economic priorities  Requirements are complex  New product line  Significant changes are expected (research and exploration).
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SDLC MODEL

  • 2. SDLC MODEL A framework that describes the activities performed at each stage of a software development project.
  • 3. SDLC PHASES  Requirements Gathering and Analysis  Design  Development  Testing  Implementation  Maintenance
  • 4. SDLC MODEL To help understand and implement the SDLC phases various SDLC models have been created software development experts, universities, and standards organizations.
  • 5. REASONS FOR USING SDLC MODEL Provides basis for project planning, estimating& scheduling. Provides framework for standard set of terminologies, activities & deliverables. Provides mechanism for project tracking and control. Increases visibility of project progress to all stakeholders.
  • 6. ADVANTAGES OF CHOOSING AN APPROPRIATE SDLC Increased development speed. Increased product quality. Improved tracking & control. Decreased project risk. Decreased project management overhead.
  • 7. COMMON LIFE CYCLE MODELS Waterfall model. Prototype model. Incremental Model. Spiral model.
  • 8. WATERFALL MODEL Requirement Design Implementation Test Maintenance  Requirement :- Defines needed information, function, behavior performance & interface.  Design :- Data structures, Software architecture, interface representation, algorithm details.  Implementation :- Source code, data base, user documentation, testing.
  • 9. WATERFALL MODEL Oldest and most well-known SDLC model. Follows a sequential step-by-step process from requirements analysis to maintenance. Systems that have well-defined and understood requirements are a good fit for the Waterfall Model. The waterfall model is also called is linear- sequentional model or classic life cycle model.
  • 10. BENEFITS OF WATERFALL MODEL Easy to understand, easy to use. Provides structure to inexperienced staff. Sets requirements stability. Good for management control (plan, staff, track)
  • 11. DRAWBACKS OF WATERFALL MODEL  All requirements must be fully specified upfront. Deliverables created for each phase are considered frozen – inhibits flexibility .  Can give a false impression of progress.  Little opportunity for customer to preview the system (until it may be too late).  The customer can see the working model of the project at the end.
  • 12. WHEN TO CHOOSE IT Requirements are very well known. Product definition is stable. Technology is understood. New version of an existing product Porting an existing product to a new platform.
  • 14. PROTOTYPING MODEL  Prototype is a working model of software with some limited functionality.  Prototype does not always hold the exact logic used in the actual software application.  Prototyping is used to allow the users evaluate developer proposals and try them out before implementation.  It helps get valuable feedback from the customer and helps software designers.
  • 15. BENEFITS OF PROTOTYPE MODEL  Increased user involvement in the product even before its implementation.  Quicker user feedback is available leading to better solutions.  Missing functionality can be identified easily.  Confusing or difficult functions can be identified.  Reduces time and cost as the defects can be detected much earlier
  • 16. DRAWBACK OF PROTOTYPE MODEL  Risk of insufficient requirement analysis owing to too much dependency on the prototype.  Users may get confused in the prototypes and actual systems.  The effort invested in building prototypes may be too much if it is not monitored properly.  The first version may have some compromises.  Some time developer may make implementation compromises to get prototype working quickly.
  • 17. WHEN TO CHOOSE IT  Software application that are relatively easy to prototype almost always involve human- machine interaction (HCI) the prototyping model is suggested.  A general objective of software is defined but not detailed input, processing or output requirements.  When the developer is unsure of the efficiency of an algorithm or the adaptability of an operating system then prototype serves as a better choice.
  • 18. INCREMENTAL MODEL Requirem ent Analysis Design Software Product Increment 1 Coding Requirem ent Analysis Design Coding Software Product Increment 2 Requirem ent Analysis Design Coding Software Product Increment n Iteration1 Iteration2 …… Iterationn Incremental Model
  • 19. INCREMENTAL MODEL  The incremental model has some phases that are in waterfall model. But it is iterative in nature.  The first increment in this model is generally a core product.  Each increment builds the product and submits it to the customer for any suggested modifications.  The next increment implements on the customer’s suggestions and additional requirement in the previous increment.
  • 20. BENEFITS OF INCREMENTAL MODEL  The incremental model can be adopted when there are less number of people involved in the project.  Customers gets important functionality early.  Lowers initial delivery cost.  Each release is a product increment, so that the customer will have a working product at hand all the time.  Requirements changes can be easily accommodated.
  • 21. DRAWBACK OF INCREMENTAL MODEL  Requires effective planning of iterations.  Problems may arise pertaining to system architecture because not all requirements are gathered up front for the entire software life cycle.  Requires early definition of a complete and fully functional system to allow the definition of increments.
  • 22. WHEN TO CHOOSE IT There is a need to get the basic functionality delivered fast.  A new technology is being used. Resource with needed skill set are not available. The domain is new to the team.
  • 24. SPIRAL MODEL  The spiral model is similar to the incremental model , with more emphasis placed on risk analysis.  Each loop in a spiral represents a development phase.  Each loop has four sections or quadrants.  The spiral model is dived in to a number of framework activities. The frame work activities are denoted by task regions.
  • 25. BENEFITS OF SPIRAL MODEL  High amount of risk analysis hence, avoidance of risk is enhanced.  Strong approval & documentation control.  Changing requirements can be accommodated.  Good for large and mission-critical projects.  Software is produced early in the software life cycle.
  • 26. DRAWBACK OF SPIRAL MODEL  Can be a costly model to use.  Management is more complex.  Not suitable for small or low risk projects and could be expensive for small projects.  Process is complex.  Spiral may go on indefinitely.  Large number of intermediate stages requires excessive documentation.
  • 27. WHEN TO CHOOSE IT  When costs and risk evaluation is important  For medium to high-risk projects  Long-term project commitment unwise because of potential changes to economic priorities  Requirements are complex  New product line  Significant changes are expected (research and exploration).