The Pervasiveness of Global Data in Evolving Software Systems

Abstract. In this research, we investigate the role of common coupling in evolving software systems. It can be argued that most software de-velopers understand that the use of global data has many harmful side-effects, and thus should be avoided. We are therefore interested in the answer to the following question: if global data does exist within a soft-ware project, how does global data usage evolve over a software project’s lifetime? Perhaps the constant refactoring and perfective maintenance eliminates global data usage, or conversely, perhaps the constant addi-tion of features and rapid development introduce an increasing reliance on global data? We are also interested in identifying if global data usage patterns are useful as a software metric that is indicative of an interesting or significant event in the software’s lifetime. The focus of this research is twofold: first to develop an effective and automatic technique for studying global data usage over the lifetime of large software systems and secondly, to leverage this technique in a case-study of global data usage for several large and evolving software systems in an effort to reach answers to these questions.

Penalties in multiple-choice and true-false questions

In multiple-choice and true-false (T-F) questions a student expresses his ignorance by leaving questions unanswered, guessing randomly, answering according to some predetermined formula or, in T-F tests, by marking all those which are unknown as 'true' or all as 'false'. Each of these no-knowledge strategies should, on average, yield the same score. It is shown that partial knowledge is awarded partmarks in multiple-choice. question and T-F tests, since the chance of guessing correctly is greater when students possess some knowledge than when they guess randomly. There is a constant relationship between the score obtained by the informed guesser and the minimum, maximum and randomguessing scores, this relationship being independent of the scoring system. Modifications of the scoring system (i.e. of the magnitude of the penalty for incorrect responses) affect only the reward for unanswered questions: in the absence of a penalty the reward for unanswered questions equals the minimum score - a score. which is unattainable by random guessing; with a large penalty the reward for unanswered questions approaches the maximum score obtainable

Comparing Private and Public Sector on Information Systems Development and Maintenance Efficiency

Part 5: EvaluationInternational audienceThis paper provides a comparison between public and private organizations on key figures relative to the information systems support activities. Many have claimed that public sector has a less satisfactory conduct of information system support than private sector. In this article we present selected data from survey investigations performed among Norwegian organizations on how they conduct information systems development and maintenance. This investigation has earlier been compared with similar investigations of this sort. A major finding from the previous comparisons is that even if we witness large changes in the underlying implementation technology and approaches used, a number of aspects such as the overall percentage of time used for maintaining and evolving systems in production compared to time used for development is remarkably stable. When we compare public and private organizations in the last survey, we find a small difference on some variables, but these are not statistically significant, thus cannot be used to conclude that IT development and evolutions is conducted more poorly in public sector than in private sector

The inevitable pain of software development: Why there is no silver bullet

Abstract. A variety of programming accidents, i.e., models, methods, artifacts, and tools, are examined to determine that each has a step that programmers find painful enough that they habitually avoid or postpone the step. This pain is generally where the programming accident meets requirements, the essence of software, and their relentless volatility. Hence, there is no silver bullet.