The CP-6 operating system and its compilers, databases, communications, and end-user interfaces were designed, developed, tested, and installed at customer sites in three years from the date the project began. This paper describes the history of this project, the methodology used to produce the 4.7 million lines of code, and the metrics covering development productivity and software quality over
... [Show full abstract] 18 releases in the last 12 years. The rigorous methodology and standards used throughout the project, which cover the full lifecycle of design, development, and support, include a statistical database covering development manpower, lines of code produced, and error reports covering 12 years in customer installations. The project achieved software development productivity rates twice as high as those of comparable projects, and error rates half those of comparable projects for product software. The key lessons learned may be applied to other software development projects.