software development processes


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software development processes

  1. 1. Software Development Models<br />MuwaffaqSalman<br />ShanatanuTyagi<br />Brian Simmons<br />Mark Quinn<br />
  2. 2. Software Development Process<br />A software development process or life cycle is a structure imposed on the development of a software product<br />There are several models for such processes<br />Each model describes approaches to a variety of tasks or activities that take place during the process.<br />
  3. 3. Some Development Models<br />Waterfall Model<br />Incremental Model<br />Spiral Model<br />
  4. 4. Waterfall Model<br /><ul><li>Also known as System Development Life Cycle (SDLC) Model or Linear Sequential Model
  5. 5. It is a linear and sequential software development process
  6. 6. It consists of phases such; as 1)Requirements analysis, 2)Design, 3)Implementation, 4)Testing, 5)Installation, 6)Maintenance
  7. 7. Once a phase of development is completed, the development process (or “flows” hence the name waterfall) proceeds to the next phase and cannot turn back</li></li></ul><li>Advantages of Waterfall Model<br />The emphasis on requirements and design before writing a single line of code ensures minimal wastage of time and effort<br />Getting the requirements and design out of the way first also improves quality and saves on cost as it's much easier to catch and fix bugs at the design stage than at the testing stage<br />Easy to understand as it’s structured, disciplined and progresses linearly through easily explainable phases<br />
  8. 8. Disadvantages of Waterfall Model<br />It is seen as somewhat unrealistic and unsuitable for the real world because of it’s upfront requirements<br />Inflexible as it’s difficult revisit phase once it’s completed phase<br />Costly to change scope and requirements<br />
  9. 9. Incremental Model<br /><ul><li>Developed in response to the weaknesses of the waterfall model
  10. 10. The Incremental model gives a particular amount of risk containment. Unless a problem was universal it would not hold up the perfect development process as the other components would still continue to develop in self-supporting
  11. 11. There are 2 incremental models as seen in figure 1 and figure 2
  12. 12. Both use the “Divide and Conquer” methodology where a large complex problem is separated into smaller parts </li></li></ul><li>Advantages of Incremental Model<br />Generates working software quickly and early during the software life cycle<br />More flexibility – less costly to change scope and requirements<br />Easier to test and debug during a smaller iteration<br />Easier to manage risk because risky pieces are identified and handled during its iteration<br />Each iteration is an easily managed milestone<br />
  13. 13. Disadvantages of Incremental Model<br />Each phase of an iteration is rigid and do not overlap each other<br />Problem may arise pertaining to system architecture because not all requirements are gathered up front for the entire software life cycle<br />
  14. 14. Spiral Model<br /><ul><li>Also designed in order to overcome the disadvantages of the waterfall model
  15. 15. Activities are organised in a spiral shape and divided into four quadrants
  16. 16. First Quadrant: focuses on gathering an understanding of the objectives
  17. 17. Second Quadrant: is to evaluate any alternatives and identify risks associated with these alternatives
  18. 18. Third Quadrant: If performance and other technical and operational issues are resolved the activities to develop and verify next-level product are performed
  19. 19. Fourth Quadrant: is a technical review carried out in order to asses, the status progress, maturity and risk of development to date.</li></li></ul><li>Advantages of Spiral Model<br />Increased risk analysis<br />Implementation has priority over functionality <br />Functionality can be added later<br />
  20. 20. Disadvantages of Spiral Model<br />Limited reusability<br />Risk of not meeting deadlines or exceeding budget <br />Possibility to end up using the waterfall model<br />