Waterfall organizes software delivery as a sequence: gather requirements, create a design, turn it into a work program, implement, test, and obtain user acceptance. section 1.3
Its structured sequence creates predictable handoffs but exposes important delivery risks:
- Disconnecting users from implementation can produce software that does not meet real needs. section 1.3
- Separating project managers from implementation makes complexity and cost harder to estimate accurately. section 1.3
- Big requirements upfront became less attractive as project complexity and uncertainty increased. section 1.3
Later adaptations added feedback between stages, while Spiral and V-model approaches explored alternatives. Agile shifted emphasis toward working software, customer collaboration, and accepting change. section 1.3
