**Category:** Development Methodologies **Tags:** - Project Management - Methodology **Abstract:** The waterfall model is a breakdown of project activities into linear sequential phases, where each phase depends on the deliverables of the previous one and corresponds to a specialization of tasks. ![[waterfall.png]] The waterfall development model originated in the manufacturing and construction industries; where the highly structured physical environments meant that design changes became prohibitively expensive much sooner in the development process. When first adopted for software development, there were no recognised alternatives for knowledge-based creative work. In Royce's original waterfall model, the following phases are followed in order: - **System and software requirements:** captured in a product requirements document - **Analysis:** resulting in models, schema, and business rules - **Design:** resulting in the software architecture - **Coding:** the development, proving, and integration of software - **Testing:** the systematic discovery and debugging of defects - **Operations:** the installation, migration, support, and maintenance of complete systems ## Notes - Waterfall has mostly fall out of style on favour of approaches like Agile - Waterfall has severe downfalls on situations where requirements are not clear at the begining of the project or adjusting for changes. ## Links - [Waterfall - Wikipedia](https://en.wikipedia.org/wiki/Waterfall_model)