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List processing systems should be designed to facilitate production of large programs to manipulate large complex symbolic data stores. This paper presents an overview of a number of system features which the author feels are important to improve the productivity of programmers working in such domains. A systems view is taken, rather than focusing just on language features, since algorithms must be not only coded in a language form, but debugged, modified, made efficient, and run on data Because of this general framework, the requirements specified are applicable to the design of advanced programming systems for a wide range of applications Three aspects of programming systems are highlighted good interactive facilities, programmable control structures, and sophisticated data communication mechanisms Interactive features are described to facilitate program composition, entry, testing, debugging, editing, optimization, and packaging. Implementation of a generalized environment structure model specified would allow programming of various control regimes including multi processes, coroutines and backtracking. Alternative methods of procedure invocation required include invocation by pattern and by monitoring condition. The need for extended data forms, storage management, and extensibility are stressed, as is the duality of data retrieval and function evaluation. Syntax directed input and output of data would facilitate use of complex data stores. [ABSTRACT FROM AUTHOR]

The pedagogical advantages of a general purpose interactive system called NEWBASIC CATALYST are discussed. NEWBASIC CATLYST incorporates an advanced implementation of BASIC, system-level interactive features, and a general capability for extension through user oriented function attachment. Application of this last feature to provide a flexible CAI scan capability is illustrated. An example of interaction at the system level shows how students: can mix the advantages of independent or "solo" mode computing with those of guided or "dual'' mode interaction. Preliminary experience with the system in an urban secondary school setting is discussed. [ABSTRACT FROM AUTHOR]

Experiments designed to evaluate the capabilities of mechanized information retrieval systems, with emphasis on interactive (man-machine) language and on some of the mechanical and psychological limitations in their design, were conducted at the Moore School Information Systems Laboratory The bask assumption of the research is that an information retrieval system that provides for man-machine dialogue cat a remote inquiry terminal should provide a searcher with many of the tools Which would be available to him were he actually performing his search at a library or repository of documents. Factors involved in evaluation of such a system include ease of use, learning time, and effectiveness of actual retrieval. Three experiments and the conclusions resulting from them are detailed. [ABSTRACT FROM AUTHOR]