Sotware Life Cycle Models

Vision – focus on why Definition – focus on what Development – focus on how Maintenance – focus on change

A lifecycle model is a series of steps through which the product progresses.

These include

  1. requirements
  2. phase
  3. specification phase
  4. design phase
  5. implementation phase
  6. integration phase
  7. maintenance phase
  8. retirement

Software Development Lifecycle Models

  • Build-and-fix model
  • Waterfall model (linear sequential model)
    • Requirement Analysis and Definition
    • System and Software Design
    • Implementation and Unit Testing
    • Integration and system testing
    • Operation and Maintenance
  • Rapid prototyping model
  • Incremental model
  • Extreme programming (Rapid Application Development)
    • Another form of incremental model.
    • Fully functional system is very short (2-3 Months).
    • Requirements are well understood and project scope is constrained.
  • Synchronize-and-stabilize model (Used by Microsoft)
    • requirements have been captured by interviews,
    • project is then divided into 3 or 4 builds.
    • Each build is carried out by small teams working in parallel.
    • At the end of each day the code is synchronized (test and debug) and at the end of the build it is stabilized by freezing the build and removing any remaining defects.
  • Spiral model ( developed by Barry Boehm)
    • Waterfall model plus risk analysis
  • Object-oriented life-cycle models (iteration, parallelism, and incremental development.)
    • eXtreme Programming
      • pair programming.
        • In this, a team of two developers develop the software, working in team as a pair to the extent that they even share a single computer.
        • client representative is always present
      • user requirements are captured through stories.
      • Estimate for duration and cost of each story is then carried out
      • Stories for the next build are selected.
      • Then each build is divided into tasks
      • Test cases for task are drawn up first
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