A developer's knowledge of a computing system's requirements is necessarily imperfect because organizations change. Many requirements lie in the future and are unknowable at the time the system is designed and built. To avoid burdensome maintenance costs developers must therefore rely on a system's ability to change gracefully-its flexibility. Flex
Bruce Johnson is Docent and Visiting Professor, Cultural History, University of Turku (Finland); Adjunct Professor, Contemporary Music Studies, Macquarie University (Sydney, Australia); Honorary Professor, Department of Music, University of Glasgow (Scotland, UK).