May 1984 - Vol. 27 No. 5
Features
The legal protection of computer software
As new as the technology itself, a sometimes confusing array of legal protections are now available to safeguard the huge investment of time and money that goes into the development of sophisticated commercial software.
Accommodating uncertainty in software design
Recognition that most software is domain dependent (DD) is extremely important because the most commonly used software life-cycle models are not adequate for DD software. The nature of DD software, and the need to manage its life cycle effectively, calls for a new approach to software design and the implementation of software development environments.
A virtual memory system for picture processing
A virtual memory system designed specifically for picture processing, Raster Handler 2 provides programs with efficient access to pixels. It features square partition of images, imbalanced allocation of frames, and nondemand page replacement. RH2 is implemented in software and incorporates a prepaging algorithm designed specifically for picture processing.
An algorithm for optimized Boolean evaluation in information management systems
In cases where simple data validation techniques are inadequate and optimization policies relatively complex (e.g., in health and medical systems), a Boolean optimization algorithm can be used to report errors accurately and unambiguously. The algorithm is presented in the context of a data-validating software module that uses an LR(1)-parser. The algorithm's precision makes it of potential use for the retrieval of records that nearly satisfy a query.
Evolution and organizational information systems: an assessment of Nolan's stage model
Richard Nolan's stage model is the best known and most widely cited model of computing evolution in organizations. The model's development over a decade demonstrates its own evolution from a simple theory, based on the factoring of change states indicated by changes in computing budgets, to an elaborate account of the characteristics of six stages of computing growth. An analysis of the model's logical and empirical structure reveals a number of problems in its formulation that help to account for the fact that its principal tenets have not been independently validated. The model is shown to be an “evolutionistic” theory within the theories of evolution in the social sciences, focusing on assumed directions of growth and an implied end state toward which growth proceeds, and suffering from problems inherent in such theories. Further research based on an “evolutionary” view of computing growth is suggested as a means of improving theories of computing in organizations.
A critque of the stage hypothesis: theory and empirical evidence
The stage hypothesis on the assimilation of computing technology provides one of the most popular models for describing and managing the growth of administrative information systems. Despite little formal evidence of its reliability or robustness, it has achieved a high level of acceptance among practitioners. We describe and summarize the findings of seven empirical studies conducted during the past six years that tested various hypotheses derived from this model. The accumulation of evidence from these studies casts considerable doubt on the validity of the stage hypothesis as an explanatory structure for the growth of computing in organizations.
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Design of the S system for data analysis
S is a language and system for interactive data analysis and graphics. It emphasizes interactive analysis and graphics, ease of use, flexibility, and extensibility. While sharing many characteristics with other statistical systems, S differs significantly in its design goals, its implementation, and the way it is used. This paper presents some of the design concepts and implementation techniques in S and relates these general ideas in computing to the specific design goals for S and to other statistical systems.
