Other SDLC Models

Waterfall with Prototyping

Prototyping to analysis and design phases

  • Preview and validation of User Interface by customer.
  • Preview and validation of complex workflows by customer.
  • Technical risks mitigation etc. Feasibility.

    Biggest Risks

  • Correctness and completeness of earlier phases is a prerequisite of each phase.
  • Risks related to complex functionalities and large size of projects.
  • Might not handle all scenarios.


Evolutionary Prototyping Methodology.

  1. Here the system concept evolves during the project
    • Develop a prototype
    • Show it to customer. Get their feedback.
    • Refine the prototype. Repeat till prototype is “good”.
    • Complete any pending work and release the product.
  2. Appropriate when
    • Rapidly changing requirements
    • Customer can not commit to a set of requirements. Poor understanding of the application area (by customer or developer).
    • Poor understanding of technology, architecture or algorithms.
  3. Problems
    • Cant predict efforts, size, costs.
    • Demands on good engineering, to ensure sustaining every iteration.


Rapid Application Development

  1. Modified waterfall model that emphasizes an extremely short development life cycle
    • Methodology driven by tools which achieve rapid development
      • Joint Requirements Planning
      • Joint Application Development
      • Construction
      • Cutover
    • Costs of rework is very less. So, design and testing phases and shortened
  2. Appropriate if the requirements can be realized using the tools
    • CASE tools (such as VB, Borland Delphi, PowerBuilder etc.)


Product Lifecycle Models

  1. Modification of iterative model
    • Multiple cycles of development, adding newer features in every cycle.
    • Requirements driven by the market, not by specific customers.
      • Influenced by competing products.
      • Present customer base as well as targeted customers.
  2. Each cycle builds on earlier cycle’s work products
    • Stable architecture and standard development practices.
    • Requirements gathering and analysis is more tedious.
    • HLD and architecture inherited from earlier cycles.
    • DD & CUT combined to one stage.
    • System testing is elaborate.
    • Customer testing is more tedious: alpha and beta.
  3. Biggest Risks and Challenges
    • Conflicting requirements from diverse customer base.
    • Need to rapidly change to adapt to changing market pressures.