Users of computer systems are now accustomed to the convenience of online help systems and generally demand these amenities in the computers they buy. However, recent studies as to the efficacy of certain types of assistance for certain classes of users raise important questions for designers.

As part of the program to provide information to Federal agencies on software tools for improving quality and productivity in software development and maintenance, data was collected on software engineering environments. Software engineering environments surround their users with software tools necessary for systematic development and maintenance of software. The purpose of this report is to characterize software engineering environments by type and by their relationship to the software life cycle and by their capabilities, limitations, primary users, and levels of support. This report provides examples of existing software engineering environments that are available commercially or in research laboratories. KEYWORDS framing environments; human factors; life cycle coverage; programming environments; software analysis; software engineering; software engineering environments; software support; software tools. FOREWORD Under the Brooks Act, the National Bureau of Standards Institute for Computer Sciences and Technology (ICST) promotes the cost effective selection, acquisition, and utilization of automatic data processing resources within Federal agencies. ICST efforts include research in computer science and technology, direct technical assistance, and the development of Federal standards for data processing equipment, practices, and software.ICST has published several documents on software tools as part of this responsibility and the growing recognition that the use of software tools and software engineering environments can reduce the effort necessary to develop and maintain computer software. The guidance is designed to assist Federal agencies in automating and standardizing their software development and maintenance projects. This report presents the results of the analysis of data and experience accumulated on software engineering environments. It characterizes environments and describes their features to enable readers to gain an understanding of how environments can aid software development and maintenance process. Future ICST documents will provide guidance in selecting and using software engineering environments.Certain commercial products are identified in this paper for clarification of specific concepts. In no case does such identification imply recommendation or endorsement by the National Bureau of Standards, nor does it imply that the material identified is necessarily the best for the purpose.

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Software tools are powerful productivity and quality aids that in many cases are not being used effectively. This report discusses an effort to lessen this problem by providing a formal way in which tools can be classified according to the features that they provide.

The original study emphasized the design phas e of a methodology . In particular, it attempted to isolate th e design phase from the implementation phase so that one coul d study the effects of one phase on the other, e .g ., a poor desig n followed by corrective implementation . In subsequent review, th e editor and other reviewers felt that this level o f differentiation added much initial complexity and risk to th e study . Consequently, the version that follows treats th e methodology as a "black box" and is therefore simpler than th e original . After this study has been successfully completed, a future study should be planned based on the outcome of this on e that attempts a higher degree of differentiation .R . Houghton, Edito r NOTE : The mention of trade names for several softwar e development methodologies does not constitute endorsement o f those methodologies by the National Bureau of Standards . Editing was performed under DoD ContractMuch has been said about the cost of software maintenance i n the Department of Defense (DoD) . In particular, one of the mai n goals of the Software Technology for Adaptable, Reliable System s (STARS) program is to reduce the cost of maintenance . Th e motivation for the study described in this paper is to hel p determine the characteristics of software developmen t methodologies that contribute to reduced costs for maintenance . When defined, these characteristics will form a basis for th e definition of standards for development methodlogies .Many recommendations have been made for improving th e process of software development over the past 30 years . Hig h level languages, timesharing systems, and programming technique s are among the ideas that have been successfully used . Many othe r ideas have been proposed, but not used extensively, making i t difficult to determine their effectiveness .The discipline of software engineering has emerged over th e past 15 years as a focal point for efforts to improve both th e quality of software products and the process by which they ar e created and evolved . After initial attempts in which isolate d methods were developed to address different phases of th e software lifecycle, recent work has concentrated on integratio n of methods .The integration of technical methods and managemen t procedures across the software lifecycle yields a mettiodo1ogy. fo r software development o a process that can be systematicall y followed from the initial system concept through product releas e and operation . The methodology may be supported by automate d tools, which may also be integrated into a programming suppor t environment . Finally, the methodology and the programmin g support environment normally are used in a work setting, one o r more physical locations in which the software development occurs .While one would like to evaluate software developmen t methodologies objectively, it is very difficult to do so sinc e they are dependent upon the programming support environment, th e software development organization applying the methodol...