Software development in the FreeBSD project is incremental in the sense that a stream of contributions, including bugfixes and minor and major new features, go into a single branch in the repository, the development branch (or 'trunk'), and are required to preserve the software in a working state. This creates a succession of development releases, akin to the practice of frequent releasing argued by Eric S. Raymond in his essay 'The Cathedral and the Bazaar' to be the key to the success of Linux and other open source projects. The positive and negative impact of this approach is discussed based on a survey involving 72 project participants. On the positive side, the data indicate that it creates a highly motivating 'see bug, fix bug, see bug fixed in new release' life cycle, and helps integrate bugfixing with new development. On the negative side, the data indicates that the highly incremental model does not support the development of complex new features.

A decentralized variant of continuous integration can be defined in terms of two fundamental rules: (1) Developers' access to add contributions to the development version at any time, and (2) developers' obligation to integrate their own contributions properly. Decentralized, continuous integration may adapt well to organizations where developers work relatively independently, as in many open source projects. The approach raises the issue of how these organizations can exercise central control, as attaining the benefits of continuous integration requires that contributions are useful and satisfy the project's definition of successful integration. We have investigated the use of continuous integration in FreeBSD and Mozilla. Our account of quality assurance activities in the two open source projects distinguishes between Mintzberg's three complementary forms of central control: Standardization and control of work output, work processes, and worker skills. Our study indicates that two major challenges face projects using decentralized, continuous integration: (1) To balance the access to add contributions against the need to stabilize and mature the software prior to a release, and (2) to consider the developers' limited time and resources when interpreting their obligation to integrate their changes properly.

Electronic banking must be secure and easy to use. An evaluation of six Danish web-based electronic banking systems indicates that the systems have serious weaknesses with respect to ease of use. Our analysis of the weaknesses suggests that security requirements are among their causes and that the weaknesses may in turn cause decreased security. We view the conflict between ease of use and security in the context of usable security, a concept that is intended to match security principles and demands against user knowledge and motivation. Automation, instruction, and understanding can be identified as different approaches to usable security. Instruction is the main approach of the systems evaluated; automation relieves the user from involvement in security, as far as possible; and understanding goes beyond step-by-step instructions, to enable users to act competently and safely in situations that transcend preconceived instructions. We discuss the pros and cons of automation and understanding as alternative approaches to the design of web-based e-banking systems.

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Delegation of authority is the basic approach to coordination of work in FreeBSD, an open source software (OSS) project that develops and maintains an operating system. This essay combines a software engineering perspective with a knowledge creation perspective to discuss three central mechanisms in FreeBSD: (1) motivation, (2) quality control by frequent building, and (3) bugfixing by parallel debugging. It is argued that frequent building is the project’s key coordinating mechanism, and that build breakdowns play a constructive role in the processes of knowledge creation in FreeBSD. Copyright Springer Science+Business Media, LLC 2007Frequent building, Knowledge creation, Open source, Quality assurance,