Class prototype


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Class prototype

  1. 1. Prototyping  SDLC approach  Sample of system is prepared  Comprehensive system  Doesn't include all user requirements  Based on evolutionary method
  2. 2. Prototyping  Rapid software development to validate requirements  Help customers & developers understand the requirements for the system  Users can experiment with a prototype to see how the system supports their work  Prototype can reveal errors and omissions in the requirements
  3. 3. Prototyping  Considered as a risk reduction activity which reduces requirements risks  Used when all requirements cannot be identified and freezed initially  Throw-away model given to user  On the basis of feedback, actual system is developed
  4. 4. Prototyping  Misunderstandings between software users and developers are exposed  Missing services may be detected and confusing services may be identified  A working system is available early in the process
  5. 5. Prototyping  The throw-away prototype should NOT be considered as a final system  Some system characteristics may have been left out  There is no specification for long-term maintenance  The system will be poorly structured and difficult to maintain
  6. 6. Prototyping- 4 steps 1. Identify user’s basic information requirements 2. Develop initial Prototype system 3. Use of Prototype system to refine the user’s requirements 4. Revise & enhance Prototype system
  7. 7. Prototyping Establish prototype objectives Define prototype functionality Develop prototype Evaluate prototype Prototyping plan Outline definition Executable prototype Evaluation report
  8. 8. Prototyping- Step 1 1. Identify user’s basic information requirements  Form of outputs required from system  Based on users’ expectations, cost of workable prototype is calculated
  9. 9. Prototyping- Step 2 2. Develop initial Prototype system  Users’ basic information requirements  Minimum possible time  Efficiency is not main consideration
  10. 10. Prototyping- Step 3 3. Use of Prototype system to refine the user’s requirements  User gains hand-on experience on initially developed Prototype  Further refinements done, if required
  11. 11. Prototyping- Step 4 4. Revise & enhance Prototype system  Make necessary changes pointed by user after using Prototype  Steps 3 & 4 are repeated again & again  Refined as per user’s satisfaction
  12. 12. Prototyping Process Determine Requirements Requirements Construct Prototype Prototype Requirements Adjustments Demonstrate Prototype OK System Implementation
  13. 13. Prototyping Benefits •Improved system usability •Improved design quality •Developers learn from customers •Additional functionality neededPossible
  14. 14. Prototyping Benefits •Improved maintainability •Reduced overall development effort •“Try Out” ideas in limited cost •Functioning system into hands of user quickly
  15. 15. Prototyping Benefits •More Flexible •Steady, visible signs of progress •A more accurate end product •Users are actively involved in the development
  16. 16. Prototyping Benefits •Errors can be detected much earlier as the system is made side by side •Quicker user feedback is available leading to better solutions
  17. 17. Limitations Customer may want the prototype delivered Process may continue forever- Scope not well defined May increase the complexity of the system
  18. 18. When to use Requirements are unstable New, original development Develop user-interfaces
  19. 19. When not to use Requirements may change Return