MINICOMPUTER PROGRAMMING LANGUAGES Walter Gorman and Michael Broussard University of Southwestern Louisiana EXPERIENCE IN THE DESIGN, IMPL~ENTATION AND USE OF PL-11, A PROGRAMMING LANGUAGE FOR THE PDP-11 Robert D. Russell Department of Mathematics University of New Hampshire Durham, New Hampshire 03824 Abstract Reduced hardware costs have made high level languages for minicomputers a necessity. A survey of some of the languages availabla (FORTRAN, BASIC, FOCAL, PL-I], C, SPL, MPL, PLM, and BgPL) demonstrates the current need for a simple, portable, and readable minicomputer language. Introduction PL-I] is a programming language for the PDP11 family of computers designed and implemented as part of the OMEGA Project at CERN (the European Organization for Nuclear Research). Its purpose is to provide an effective tool for both physicists and systems programmers to use in building real-time data acquisition systems that are online to high-energy physics experiments. It is a fairly typical member of the PL-class of programming languages (44) which are based on the initial design of PL360 (41) (See Table 1). Each of these languages represents a linguistic model of its specific machine architecture, thereby providing a Systems Implementation Language (SIL) that is extremely efficient on its target machine, yet is also highly effective for human programmers to use. The need for such a tool is obvious on all computer systems, but especially on minicomputers, where most applications are in fact "systems programs". For example, in any data acquisition environment the distinction between "user" and "operating system" largely disappears--the user's prime concern.is to handle time-dependent sequences of events involving the manipulation of special I/0 devices through direct status checking and datastreaming--all functions which are usually buried in the o p e ~ t i n g system of conventional computing systems. This paper discusses four years of experience with PL-11, especially as this relates to the general topic of SILs on minicomputers. A BALANCED VIEW OF MUMPS Anthony I. Wasserman David D. Sherertz Medical Information Science University of California San Francisco, CA 94143 Abstract The MUMPS programming system was designed and developed to facilitate shared conversational access to a hierarchically-organized data base on a small computer. The MUMPS language, which has recently been standardized, contains features for numeric and string operations, along with a built-in file system called globals, embedded in a multiprogrammed execution environment. This paper gives an overview of the MUMPS language aud a typical MUMPS System, then evaluates MUMPS in terms of modern notions of programming languages and software development. Despite the many attractive features for the development of interactive programs, MUMPS is seen to have a number of shortcomings when evaluated in this way. Among the problem areas are weakness of control structures, the ability to write selfmodifying code, the incomprehensibility of most MUMPS programs, and the lack of support given by the language to notions of abstraction and modularity. EXPERIENCES MOVING COBOL ONTO A MINICOMPUTER Steven S. Herrick Computer Linguistics Incorporated Albany, New Y o r k 12205 Abstract This paper presents some subjective experience and relative qualitative results concerning -5-

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