IA/1(ID:8181/)Information Analyzer 1 - Langefors IA language from Uni Sweden References: Historical and Technical Background To meet the needs outlined above, the Information Systems Design and Optimization System (ISDOS) Project at the University of Michigan has been studying the systems building process with the objective of developing a methodology for computer-aided design and construction of information systems. A description of the ISDOS Project can be found in Teichroew and Sayani [9]. ISDOS was born at Case Institute of Technology (now Case-Western Reserve University) in 1967 and was moved to the University of Michigan in 1968. Affiliation with Purdue University is also maintained through the efforts of Dr. Jay F. Nunamaker, an original member of the ISDOS Project at Case. The work at ISDOS has involved both the study of existing techniques for requirements statement and the development of new Requirements Statement Languages. All techniques view the problem in essentially the same way. They describe how to produce outputs from inputs. All techniques provide some method for describing data relationships as the user views them. They provide some facility for stating the requirements of the problem. Several provide some facility for stating other data such as time and volume. Young and Kent [i0] represent the earliest work. Information Algebra is the work of the CODASYL Development Committee [ii]. Two other efforts have been reported by Langefors [12 and 13] and Lombardi [14]. Accurately Defined Systems (ADS) is a product of the National Cash Register Company (IS] and is described by Lynch [16]. The Time Automated Grid (TAG) system, a product of IBM, was developed by Myers [17] and is described by Kelly [18]. ADS and TAG use a practical, straightforward approach without attempting to develop any "theory" of data processing. ADS and TAG are systematic ways of recording the information that a systems analyst would gather. ADS or TAG could be used by any experienced systems analyst with very little instruction. Young and Kent and Information Algebra represent a problem definition approach that is more concerned with developing a theory. Both use a terminology and develop a notation that Xs not at all natural to most analysts. Lombardi's approach requires the completion of the system design before it can be used and resembles a non-procedural programming language rather than an RSL. However, Lombardi's work is relevant because it presents a non-procedural technique for stating requirements once the file processing runs have been determined. Langefors' technique uses the concept of precedence relationships among processes and files without indicating how these relationships are obtained and is relevant to the analysis of a problem statement rather than to the design of a system. However, it does suggest a number of desirable features of a requirements statement technique. Despite the availability of these RSL techniques, their use has not been extensive. To the best of our knowledge, the languages of Young and Kent and of Lombardi have not been used except in an experimental way. Information Algebra has been used only once by Katz and McGee [19]. It appears that the development and use of TAG has been discontinued by IBM. ADS appears to be gaining in user acceptance. The U. S. Navy [20], in the process of designing a financial system, and a number of other firms [21] have used ADS as a requirements statement technique. This current work is the result of an evolutionary process involving several different RSL's. The first development SSL/I (SODA Statement Language/I) is the work of Nunamaker [22]. SODA (Systems Optimization and Design Algorithm) is an ISDOS software component that produces specifications for program module and storage structure and for hardware selection from the requirements analyzed by an RSA. Extension of SSL/I resulted in the development of PSL/I (Problem Statement Language/I) described by Koch, Krohn, McGrew, and Sibley [23]. Experience with PSL/I indicated its shortcomings and led to PSL/II possessing improvements suggested by Hershey, Rataj, and Teichroew [24]. Simultaneous with the development of PSL/II, experience with ADS demonstrated the value of a forms-oriented RSL for ease of requirements statement. in Proceedings of the 1974 ACM Annual Conference San Diego, November, 1974 view details |