摘要:

AbstractMost MIS expense goes into the maintenance of existing software. Estimates vary from 50% to 60% at the low end up to 90%, even 95%, depending on responsibilities and the type of software. Coming up with better ways to maintain (i.e. understand, modify and update) existing software is unquestionably the most important challenge facing the software industry today.Saddled with obsolete but essential software, a growing number of organizations are faced with a series of unpalatable choices. One option is to simply continue with the same old software, patching it where possible to meet the most pressing needs. This approach has a number of limitations not the least of which are lost opportunity and reduced competitiveness. Moreover, owing to unforeseen and increasing interactions, time per unit of change (especially structural change) tends to increase exponentially throughout the maintenance life cycle.Eventually, old systems must either undergo a major overhaul or be replaced with new ones. Properly done, and implemented, either approach can add a measure of efficiency previously impossible—and cost recovery can often be accomplished over a reasonable period of time. The initial costs involved in such renewal, on the other hand, are often prohibitive.Faced with this dilemma, what are decision makers to do? In this paper, I propose a new approach to system maintenance which can both dramatically improve systems and minimize renewal costs. In turn, I describe a typical maintenance scenario, and consider the use of CASE restructuring tools. Then I show how the human or cognitive factor impinges on the maintenance issue, and how this implies the need for abstraction. Next, we note limitations of standard “bubble chart” and other notational schemes and introduce the FLOWform representation as a means of overcoming these limitations.Finally, with this background, I describe the Cognitive Approach to Systems Engineering and Re‐Engineering (CogApp). In this context, I summarize capabilities of the PRODOC re/NuSys WorkbenchTMwhich has been used to implement the CogApp. I close with a short case history describing application of this approach, and the results obtained th

ISSN:1040-550X    

DOI:10.1002/smr.4360020302

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractCompared to a decade ago, when the first comprehensive study was done in software maintenance, many changes have occurred in the practice of system development. Longitudinal data were obtained by using the same survey instrument, updated to reflect current practices, and sampling the same population. Comparing the current with 1977 results has helped to identify the persistent problems and issues as well as the emerging problems and issues.One of the important, but somewhat disturbing, conclusions is that maintenance problems are pretty much the same as during the 1970s (except for minor changes), despite advances made in structured methodologies and techniques. In terms of specific problems, personnel problems of maintenance programmers, i.e. turnover and availability, and programmer effectiveness problems, i.e. skills, motivation and productivity, have shown a rise, while problems associated with users' knowledge of computer systems have declined.

ISSN:1040-550X    

DOI:10.1002/smr.4360020303

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

摘要:

AbstractA JSP oriented program design environment has been produced at UMIST (known asMAJIC), which computerizes the whole of the JSP methodology. This computerization of JSP has shown some shortcomings of the method with regard to the maintenance of the finished programs. The method imposes restrictions on the modification of program and data structures which reduces the effectiveness of using the method to maintain existing structures. This paper investigates some of those restrictions in the light of the work done to produce theMAJICsystem. The restrictions are centred on the JSP mechanism for data structure correspondences, which are crucial to the use of JSP. Rules are proposed by which controlled modifications may be made to Jackson structures without, as is otherwise the case, of the need to reprocess large parts of the method. The rules were made in order to make a tool based on JSP more flexible, but they may equally be applied to maintenance of structures produced manually.

ISSN:1040-550X    

DOI:10.1002/smr.4360020304

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY

ISSN:1040-550X    

DOI:10.1002/smr.4360020301

出版商:John Wiley&Sons, Ltd    

年代:1990

数据来源: WILEY