ISSN:1040-550X    

DOI:10.1002/smr.4360070102

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractThis paper explores the apparent paradox that, although performance improves with experience, the maintenance of a software system becomes more difficult as experience with it accumulates. It is asserted that this phenomenon is a side effect of the environment used to maintain the software. A decade of experience with a large and complex clinical information system is summarized to demonstrate that software maintenance may be inherently less difficult than original development. It is shown that a highly integrated, million‐line, operational system, used in life‐threatening situations, has been maintained effectively by a staff of six. During the past five years, the size of the system increased by 167%. In addition to maintaining a growing number of programs, the staff produced new programs at a rate of 0.64 programs per effort‐day. Moreover, the case study also demonstrates that this level of performance can be transported to other sites. The paper concludes with some observations regarding changes to the software process that will resolve the pa

ISSN:1040-550X    

DOI:10.1002/smr.4360070103

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractAn empirical study of software maintenance tasks was carried out in a large Norwegian organization in the period 1992–93. More than one hundred randomly selected maintenance tasks were studied through interviews with the maintainers performing the tasks immediately before they started the tasks and immediately after they had completed the tasks. The collected data is used to develop distributions and to test 33 hypotheses about software maintenance. The findings from the study indicate, for example, thatApplication system documentation plays only a minor role as maintenance information source.The maintenance productivity, measured in LOC/effort, is predicted by the size of the task and type of change in the source code, but seems rather independent of language level, maintainer experience, application age and application size.There is an economy of scale for software maintenance tasks.The type of programming language does not correlate with proportion of unexpected maintenance problems, task complexity or task size.The proportion of corrective maintenance decreases with increasing age of the applicatio

ISSN:1040-550X    

DOI:10.1002/smr.4360070104

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractMaintainers of old code often need to discover where particular program features are implemented. This paper presents a method, called ‘software reconnaissance’ for answering this question through an analysis of the execution of different test cases. The method is quite easy to implement, requiring only a test coverage monitor, some simple tools, and a surprisingly small number of test cases.A statistical case study is presented that shows the kind of results that can be obtained on a typical medium‐sized program. The method seems to be effective in identifying a small number of code components that are unique to a particular program feature, though it may not find all components that make up the feature's delocalized plan. A small protocol case study shows that professional programmers can learn to use the method quickly and can use the information that it produces.Software reconnaissance may be a simple but useful addition to the maintainer's tool kit in that it provides starting points for understanding a large program and a way of recovering some requirements traceability information from old code. For the researcher, it also provides a novel functionality ‘view’ of software that maps features to program components at different levels of

ISSN:1040-550X    

DOI:10.1002/smr.4360070105

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

摘要:

AbstractThis paper is concerned with just‐in‐time (JIT) manufacturing techniques and how they can be applied to the management of software maintenance. Traditional maintenance methods focus on the change to be made or the defect to be fixed. Their aim is to get the product working as quickly as possible. This paper argues that this approach of pushing work through the maintenance system is flawed. The experience of the manufacturing industries which have global competitors, is that focusing only on results does not win. An alternative is to concentrate on the process of software maintenance. This paper reports on initial experiments with two teams of programmers using JIT techniques for maintaining software. The purpose was to see if JIT could produce benefits when applied to this knowledge‐intensive and unpredictable task. If there is a software maintenance process, then JIT may be a way to optimize the functioning of this process. JIT requires that fault fixes or changes to the software are pulled, rather than pushed, through the maintenance process. A functioning JIT process gives immediate information on the quality of the process because programmers return any work which is not correct.The conclusion is that JIT approaches can work and do improve the quality of the maintenance done. The key impediments to using JIT in maintenance are the changes it requires in the way people work and the requirement for a different focus in the management of software mainte

ISSN:1040-550X    

DOI:10.1002/smr.4360070106

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY

ISSN:1040-550X    

DOI:10.1002/smr.4360070107

出版商:John Wiley&Sons, Ltd    

年代:1995

数据来源: WILEY