System development life cycle models
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The document discusses four software development life cycle (SDLC) models: waterfall, spiral, iterative, and compares their pros and cons. The waterfall model is a sequential approach with distinct phases and rigid deliverables. The spiral model adds risk analysis and prototyping to the waterfall model. The iterative model specifies and implements parts of the software in iterations to continually refine requirements.
System development life cycle models
- 1. SYSTEMDEVELOPMENT LIFE CYCLE MODELS
- 2. OVERVIEW SDLC models Waterfall model Iterative model Spiral model
- 3. I. SDLCMODELS Is a simplified,abstracted description of a software development process series of steps, or phases, that provide a model for the development and lifecycle management of an application or piece of software division of software development work into distinct phases or activities with the intent of better planning and management subset of the systems development life cycle Waterfall Spiral Iterative SDLC models-
- 4. II.WATERFALLMODEL Irreversible sequential approach directing development flow downwards (alike waterfall) Emphasis on planning, time schedules, target dates, budgets and implementation of an entire system at one time
- 5. II.WATERFALLMODEL(CONTINUED) Pros Simplicity Requirement stability Easy structure to inexperienced staff Effective management control (plan, staff, track) Pitfalls Conventional model Least customer participation Debug requirement to be known at an early stage for correction- else wrong development= higher cost of production Rigid deliverables created at each phase Doesn’t reflect problem solving nature of software development
- 6. III. SPIRALMODEL defined by Barry Boehm in his 1988 article A Spiral Model of Software Development and Enhancement (Waterfall + Prototype) model adds 4th generation programming languages, rapid application development prototyping and risk analysis to the waterfall model intended for large, expensive, and complicated projects
- 7. III. SPIRALMODEL(CONTINUED) Identification Design Construct/Build Evaluation and Risk Analysis A. Identification: B. Design C. Construct/Build D. Evaluation and Risk analysis .
- 9. III. SPIRALMODEL(CONTINUED) Pros Avoidance of Risk is enhanced. Strong approval and documentation control. Implementation has priority over functionality. Additional Functionality can be added at a later date. Pitfalls Highly customized limiting re-usability Applied differently for each application Risk of not meeting budget or schedule Possibility to end up implemented as the Waterfall framework
- 10. IV. ITERATIVE MODEL does not attempt to start with a full specification of requirements development begins by specifying and implementing just part of the software, which can be reviewed in order to identify further requirements more than one iteration of the software development cycle may be in progress at the same time
- 11. IV. ITERATIVEMODEL Requirements •Gather requirements and specifications for software Design •New design or extension of earlier design Implementation and test Review • Software is evaluated •Current requirements are reviewed •Changes and additions to requirements proposed • Software is coded, integrated and tested Phases:
- 12. IV. ITERATIVEMODEL Pros Easy to locate flaws due to working model of the system at a very early stage of development Corrective measures in a limited budget. Cons Applicable only to large and bulky software development projects Hard to break a small software system into further small serviceable modules.
- 13. CONCLUSION SDLC plays an important role for development of a Software product.Each SDLC phase have a separate activities which are related to next phase.