2.14. History
For the full story and citations, see "Iterative and Incremental Development: A Brief History" (IEEE Computer , June 2003, Larman and Basili), and also [Larman03]. Iterative methods go back farther than many realize. In the late 1950s, evolutionary, iterative, and incremental development (IID), rather than the waterfall, was applied on the Mercury space project, and in the early 1960s, on the Trident submarine project, in addition to many other large systems. The first published paper promoting iterative rather than waterfall development was published in 1968 at the IBM T.J. Watson Research Center.IID was used on many large defense and aerospace projects in the 1970s, including the USA Space Shuttle flight control software (built in 17 iterations averaging about four weeks each). A dominant software engineering thought-leader of the 1970s, Harlan Mills, wrote at that time about the failure of the waterfall for software projects, and the need for IID. Tom Gilb, a private consultant, created and published the IID Evo method in the 1970s, arguably the first fully-formed iterative method. The USA Department of Defense had adopted a waterfall standard in the late 1970s and early 1980s (DoD-2167); by the late 1980s they were experiencing significant failure (estimates of at least 50% of software projects cancelled or unusable), and so it was dropped, and eventually (starting in 1987) replaced by IID method standardsalthough the legacy of waterfall influence still confuses some DoD projects.Also in the 1980s, Dr. Frederick Brooks (of Mythical Man-Month fame), a major software engineering thoughtleader of that decade, wrote and spoke about the shortcomings of the waterfall and the need to instead use IID methods. Another 1980s milestone was the publication of the spiral model risk-driven IID method by Dr. Barry Boehm, citing the high risk of failure when the waterfall was applied.By the early 1990s, IID was widely recognized as the successor to the waterfall, and there was a flowering of iterative and evolutionary methods: UP, DSDM, Scrum, XP, and many more.