This document discusses the phases of the software development life cycle according to Walker Royce's model. It describes the four phases: inception, elaboration, construction, and transition. The inception phase involves establishing objectives, scope, and initial architecture. The elaboration phase builds a prototype to validate the architecture. The construction phase integrates all components through testing. Finally, the transition phase prepares the software for deployment through activities like beta testing, training, and conversion. The model emphasizes separating research, design, and production activities for successful software development.