Software Development Life Cycle

Software Development Life Cycle

1. Objectives

   • At the completion of this chapter, you will be able to:
     • ● Define software development life cycle.
     • ● Describe the Waterfall life cycle model.
     • Describe the V-Shaped life cycle model
     • Describe the Incremental life cycle model
     • ● Describe the Spiral life cycle model.

2. Pre-Test Questions

   • The answers to these questions are in Appendix A at the end of this manual.
     • What is a software development life cycle?
     • What are the four main phases of the general software development life cycle model?

3. Software Development Life Cycle Model

   • The term software development life cycle model is a way of describing the planning, designing, coding, and testing of a software system, as well as the method in which these steps are implemented. A variety of life cycle models exist, but they all include the same constituent parts. All life cycle models take a project through several primary phases: a requirements-gathering phase, a design phase, a construction or implementation phase, and a testing phase
     • Requirements
     • Design
     • Implementation
     • Testing

4. Waterfall Life Cycle Model

   • The Waterfall life cycle model, also known as the classic or linear-sequential life cycle model, is one of the simplest to understand and use. The Waterfall model is characterized by a series of steps that must be completed in a linear, sequential order.
     • Requirements
     • Design
     • Implementation and Unit Testing
     • Integration and System Testing

5. V-Shaped Life Cycle Model

   • Like the Waterfall model, the V-Shaped life cycle model provides a sequential path of discrete phases that must each be completed before development proceeds to the next phase.
     • System Test Planning
     • Requirements
     • Low Level Design
     • High Level Design
     • Unit Test Planning
     • Unit Testing
     • Integration Test Planning
     • System Testing
     • Implementation

6. Incremental Life Cycle Model

   • The Incremental life cycle model builds an iterative approach into the Waterfall model. Development projects are divided into several smaller, more manageable iterations. Each iteration passes through a mini-Waterfall process
     • Requirements
     • Design
     • Implementation and Unit Testing
     • Integration and System Testing
     • Operation

7. Spiral Life Cycle Model

   • The Spiral life cycle model is similar to the Incremental model but incorporates risk analysis. It is divided into four phases: planning, risk analysis, engineering, and evaluation

8. Summary

   • As a formalized approach to software development, the Waterfall model is simple and easy to use. This model can be easy to implement and manage because each phase has a specific purpose, and development occurs in only one phase at a time.

9. Post-Test Questions

   • Although the Waterfall model provides a good introduction to software life cycle models, its usefulness is limited. Due to the rigidity of the model, all requirements must be stated explicitly before development begins. If requirements change or are added, the project must start over from the beginning