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The article informs about some activities of the Association for Computing Machinery (ACM). The ACM's Washington D.C. Chapter's 1973 Technical Symposium will take place at the National Bureau of Standards, Oaithersburg, Maryland, on June 21. Program Chairman is Helmut E. Thiess. The article also informs that the 4th Annual Symposium of the ACM Special Interest Group on Computer Systems Installation Management is scheduled for October 18-19 in Las Cruces, New Mexico. Papers are invited on the following topics: security; virtual systems evaluation; data entry systems-COM; personnel evaluation, measurement, and development; nonprofessional status of data processing personnel; job estimation; etc. The American Society of Indexers will hold its Second Annual All-Day Meeting on Saturday, April 28, at the Graduate Center of the City University of New York. Editors, indexers, librarians and index users will participate in forums and speeches concerned with "Index Traps and Pitfalls: Human Generated/Computer Generated." Three speakers for the morning session include Jessica L. Harris, a professor.

Comments on the research paper "Accommodating Standards and Identification of Programming Languages," by Calvin N. Mooers. Opinion that Mooer's approach to programming language via the route of trademark and service mark protection seems ill-advised; Comment that the purpose of the trademark concept is to protect the commercial value of the name of a product, not the integrity of the product itself; View that the most complex thing industrial standardization bodies have ever attempted is the standardization of programming languages.

The paper describes a scheme for symbolic manipulation of index expressions which arise as a by-product of the symbolic manipulation of expressions in the matrix calculi described by the authors in a previous paper. This scheme attempts program optimization by transforming the original algorithm rather than the machine code. The goal is to automatically generate code for handling the tedious address calculations necessitated by complicated data structures. The paper is therefore preoccupied with "indexing by position." The relationship of "indexing by name" and "indexing by position" is discussed. [ABSTRACT FROM AUTHOR]

A calendar of events for the Fall Joint Computer Conference 1968 technical program is presented. Information about several papers that will be discussed at a symposium including doctor Sanford Elkin's "Reliability, Maintenance, Error Recovery in Third Generation Systems" and doctor Glen Lewis "Applied Mathematics" is presented.

One of the most salient characteristics of extensible machines (EM) is the facility for providing system control over program-to-program and program-to-data linkage (e.g., address connection). It is the intent of this paper to expand and clarify the remarks concerning program-to-program and program-to-data linkage that were embodied in the authors' previous paper on the EM concepts, and to, finally, trace the employment of linkage mechanisms through various levels of programming languages. [ABSTRACT FROM AUTHOR]

The article provides information on the upcoming symposiums related to the computer engineering in 1966. A one-day symposium will be sponsored by ACM, SIAM and Florida State University on March 14 on "The Recommended Impact of Computer Applications on the Undergraduate Mathematics Curriculum." The four New York Metropolitan Area chapters will hold a one-day symposium in New York City on March 18. A session of invited papers will be devoted to "The Application of Computers to the Problems of a Metropolitan Society." In addition, a session of contributed papers on any topics in the computer field is now in the process of being organized . Automatic Data Processing exhibits and workshops headline the Federal Government Accountants Association 15th National Symposium, in Minneapolis, June 15-17. Topics include "Case Studies in ADP," "Programming: The Modern Budget Officer's Tool," and "The Future of Computers in the Federal Government." The Instrument Society of America (ISA) has invited papers for presentation at the 21st Annual ISA Conference and Exhibit, to be conducted October 24-27 in New York City. Theme of the meeting is "Instrumentation for an Urban Society."

The article presents news related to the Association for Computing Machinery (ACM). The new position of Director of Administration has been established at ACM Headquarters and Joseph Saetta has been hired to fill it. The position collects into one department the activities of three units which were previously in different department. They are--first, the unit which handles all membership, subscription, and single copy transactions; second, the unit which handles purchasing, the stock room, and incoming and outgoing mail; and third, the accounting unit. The Second ACM Symposium on Symbolic and Algebraic Manipulation will be held on March 23-25, 1971, at the International Hotel in Los Angeles, California. The Special Interest Group on Symbolic and Algebraic Manipulation is sponsoring the symposium, with the Special Interest Group on Artificial Intelligence as a co-sponsor. The symposium will cover developments in the field in the past five years. A number of sessions of contributed papers are scheduled, and approximately ten invited tutorial papers will survey key subject areas. The symposium will be of interest to users of both symbolic and manipulation systems as well as to system developers.

This paper discusses both the history and future of programming languages (= higher level languages). Some of the difficulties in writing such a history are indicated. A key part of the paper is a tree showing the chronological development of languages and their interrelationships, Reasons for the proliferation of languages are given. The major languages are listed with the reasons for their importance. A section on chronology indicates the happenings of the significant previous time periods and the major topics of 1972. [ABSTRACT FROM AUTHOR]

STAGE2 is the second level of a bootstrap sequence which is easily implemented on any computer. It is a flexible, powerful macro processor designed specifically as a tool for constructing machine-independent software. In this paper the features provided by STAGE2 are summarized, and the implementation techniques which have made it possible to have STAGE2 running on a new machine with less than one man-week of effort are discussed. The approach has been successful on over 15 machines of widely varying characteristics. [ABSTRACT FROM AUTHOR]

The article presents information on congresses related to the computer and information processing industry in the U.S. The first annual IEEE Computer Conference will be held at the Edgewater Beach Hotel in Chicago on September 6-8. The conference will be sponsored by the IEEE Computer Group in cooperation with Northwestern University and the IEEE Chicago section. GUIDE International, an organization for large-scale IBM computer users, will hold its next regular session at the Americana Hotel in New York City, May 23-26. The Instrument Society of America (ISA) has invited papers for presentation at the 22nd Annual ISA Conference and Exhibit, to be conducted in Chicago, Illinois, during September 11-14, 1967. The four-day conference will highlight "Instrumentation in the Service of Man." The Eighth International Electronic Circuit Packaging Symposium will be held concurrently with WESCON 67 in San Francisco, during August 21-22, 1967, one week before ACM's National Conference in Washington D.C.

A previous paper presented an efficient algorithm, called the Recomputation Algorithm, for evaluating a rational expression to within any desired tolerance on a computer which performs variable-precision arithmetic operations. The Recomputation Algorithm can be applied to expressions involving any variable-precision operations having O(10-... + Σ ∣ε∣) error bounds, where p denotes the operation's precision and ε, denotes the error in the operation's with argument. This paper presents an efficient variable-precision exponential operation with an error bound of the above order. Other operations, such as log, sin, and cos, which have simple series expansions, can be handled similarly. [ABSTRACT FROM AUTHOR]

The article presents information on various chapters of the Association for Computing Machinery (ACM) across the U.S. The Greater Rio Grande Chapter of ACM has recently extracted from its files a list of the titles of all technical papers presented at Chapter meetings since its inception in 1957. Using a program developed by D.K. Robbins of Sandia Corp., a KWIC-type listing of permuted titles of these papers has been made. This listing has been distributed to all members of the Chapter. Topics and speakers at ACM Chapters across the U.S. indicate the current trends of interest in computer science and data processing. The ACM Tidewater Chapter is sponsoring this spring a professional development course on "Real-Time Computing." The course is given by the Chapter's professional development chairman, Cecil Frost, who is applications staff specialist for Control Data Corp. At its April 21, 1966 meeting, the Westchester-Fairfield Chapter heard William Orchard-Hays speak on "Linear Programming of Computational Techniques."

The article presents information on Swedish adding machine maker Addo, that has come up with a new electronic data processing equipment, that punches error-free paper tape that can be read by an electronic computer. The Addo equipment prevents a wrong sequence or combination of numbers from getting into the computer. Addo managing director Gunnar Agrell says that adding machines could be used to punch computer paper simultaneously.

The article presents information on the National Computer Conference and Exhibit (NCCE). It is the single annual national computer conference of the American Federation of Information Processing Societies. For and by computer specialists and end users, the 1974 NCCE will take place from May 6 to May 10, 1974, at Chicago, Illinois' McCormick Place. Stephen S. Yau, general conference chairman, states that emphasis at NCCE 74 will be on present and future applications of data processing equipment and techniques, with special attention to computer productivity as it relates to the user. Data processing products and services will be shown by more than 250 exhibitors in over 800 booths. Almost every phase of computer science and data processing will be assessed in 119 sessions scheduled throughout the five days. Under the direction of Theodore M. Bellan, vice president of Computer Services for McDonnell Douglas Automation Company, the NCCE program will offer in-depth coverage of ten critical user areas and of five specific areas in computer science and technology.

An increasing amount of software is being implemented in a portable form. A popular way of accomplishing this is to encode the software in a specially designed machine-independent language and then to map this language, often using a macro processor, into the assembly language of each desired object machines The design of the machine-independent language is the key factor in this operation. This paper discusses the relative merits of pitching this language at a high level or a low level, and presents sonic comparative results. [ABSTRACT FROM AUTHOR]

The consecutive retrieval property is an important relation between a query set and record set. Its existence enables the design of an information retrieval system with a minimal search time and no redundant storage. Some important theorems on the consecutive retrieval property are proved in this paper. Conditions under which the consecutive retrieval property exists and remain invariant have been established. An outline for designing an information retrieval system based on the consecutive retrieval property is also discussed. [ABSTRACT FROM AUTHOR]

The article presents news briefs related to the Association for Computing Machinery (AMC). A list of the newly appointed chairman of AMC chapters is presented, including Raymond R. Casey and C. D. Shephard. The AMC 70 Steering Committee is planning a data processing conference based on the concept that computers will meet the challenge of man's future. The American National Standards Committee X3, Computers and Information Processing held its first meeting in Scottsdale, Arizona on January 22-23, 1970.

Sussenguth suggests in a paper (1963) that a file should be organized as a doubly-chained tree structure if it is necessary both to search and to update frequently. Such a structure provides a compromise between the fast search/slow update characteristics of binary searching and the slow search/fast update characteristics of serial searching. His method, however, contains the limiting restriction that all terminal nodes lie on the same level of the tree. This paper considers the effect of relaxing this restriction. First, trees which have the property that a priori the filial set of each node is well defined are studied. It is proved that coding the nodes within each filial set with respect to the number of terminal nodes reachable from each is necessary and sufficient to guarantee minimum average search time. Then the more general case (that is, where the entire structure of the tree is changeable) is treated. A procedure is developed for constructing a tree with a minimum average search time. A simple closed expression for this minimum average search time is obtained as a function of the number of terminal nodes. The storage capacity required to implement the doubly-chained tree structure on a digital computer is also determined. Finally, the total cost of the structure, using Sussenguth's cost criterion, is computed. It is shown that significant improvements in both the average search time and the total cost can be obtained by relaxing Sussenguth's restriction that all terminal nodes lie on the same level of the tree. [ABSTRACT FROM AUTHOR]

A simple broad-based approach for programming decision tables in FORTRAN or COBOL is developed and presented. With inputs in standard form, as defined in the paper, the programming of any decision table can be done with one or two FORTRAN statements, or with two COBOL statements, if the COMPUTE verb is available in the COBOL processor. It is shown that the method is applicable even when there are more than two mutually exclusive states of one, two or more table conditions. It is further shown that multi-state conditions in decision tables can often simplify the programming. The method outlined has the further advantage that all possible combinations of conditions are considered. It is shown that the suggested procedure is easily implemented in ALGOL. [ABSTRACT FROM AUTHOR]

The article presents information related to the Association for Computing Machinery (ACM). Jay Wright, technical program chairman for ACM66, has reported that the response to the "Call for Papers" has been good. Wright stated that 105 papers were submitted. David F. Weinberg, general conference chairman, has announced that plans for the meeting are taking shape under the able handling by the Conference Committee. The 1966 ACM Roster of membership information came off the press on April 8, 1966 reflecting the full membership as of the first of the year. The new Roster is a significant improvement over previous issues. Each entry, clearly and compactly printed, now gives the individual's title of address and also the earliest year when his present uninterrupted span of membership in ACM started. Auxiliary information includes ACM officers and Council members, ACM chapters with chairmen's names, a list of ACM Institutional members, and a listing of the geographical areas where ACM members are located--by country, state and city.

The article discusses the role of the man as an Information-Processing System. The International Federation for Information Processing (IFIP) will conduct a session regarding technological innovations in data processing. Computer system design which has been patterned on man as recently been moving away from totally central control system design concepts headed for decentralized control concepts. Chairman of the session will be Isaac L. Auerbach which is also the president of IFIP. The plans of this computer organization will make a big progress in information technology.

Users of linear programming computer codes have realized the necessity of evaluating the capacity, effectiveness, and accuracy of the solutions provided by such codes. Large scale linear programming codes at most installations are assumed to be generating correct solutions without ever having been "benche-marked" by test problems with known solutions. The reason for this fail- ure to adequately test the codes is that rarely are there large problems with known solutions readily available. This paper presents a theoretical justification and an illustrative implementation of a method for generating linear programming test problems with known solutions. The method permits the generation of test problems that are of arbitrary size and have a wide range of numerical characteristics. [ABSTRACT FROM AUTHOR]

Programming systems which permit arbitrary linked list structures enable the user to create complicated structures without sufficient protection. Deletions can result in unreachable data elements, and there is no guarantee that additions will be performed properly. To remedy this situation, this paper proposes a Data Structure Description and Manipulation Language which provides for the creation of a restricted class of data structures but ensures the correctness of the program. This is accomplished by an explicit structure declaration facility, a restriction on the permissible operations, and execution-time checks. [ABSTRACT FROM AUTHOR]

This article discusses various issues related to the three-dimensional plot programming and algorithm 483. PLOT3D will accept three-dimensional data in various forms, rotate it in three-space, and plot the projection of the resulting figure onto the x-y plane. Those lines or portions of lines that should be hidden by previous lines are masked. Each call to PLOT3D causes one line to be plotted. A line consists of a sequence of points in three-space that will be connected using linear interpolation between adjacent points. This sequence of points is specified by three sequences of real numbers, the x, y, and z components of each point. Each of these sequences of real numbers can be specified either as being equally spaced, and therefore denoted by an initial value and an increment, or as being contained in a real array. PLOT3D attempts to minimize plotter movement by beginning at the alternate end of successive lines. A more detailed description of the parameters is contained in the comments at the beginning of the program listing. This routine was developed at the Applied Research Laboratories on their Control Data Corp. 3200 computer system.

A data definition language is a declarative computer language for specifying data structures. Most data definition languages concentrate on the declaration of logical data structures with little concern for how these structures are physically realized on a computer system. However, the need for data definition languages which describe both the logical and physical aspects of data is increasingly apparent. Such languages will be a key element in the translation of data between computer systems, as well as in advanced data management systems and distributed data bases. This paper reviews past work in the data definition language for describing both logical and physical aspects of data. Applications of these "generalized" data definition languages are also discussed. [ABSTRACT FROM AUTHOR]

The article focuses on the 29th annual meeting of the Association for Computing Machinery (ACM). The ACM 74, to be held at the San Diego Convention Center, in November 1974, promises to be one of the most accommodating and exciting conferences ever held. The technical program chairman, David Bulman has designed the program to inform through controversy as well as exposition. ACM 74 will be a particularly well-balanced conference with virtually each special interest group (SIG) sponsoring one or more technical sessions. However, unlike previous ACM conferences, this one has more sessions provided through the SIG for Business Data Processing. The ACM SIG for Computers and the Physically Handicapped will underline the role of the computer in medicine with papers on "Modes of Information Presentation for the Blind Programmer," and "Computer Applications in Artificial Limb Research." For the fifth year, ACM will host the annual U.S. Computer Chess Championship Tournament in which computer programs meet in open competition.

The article states that computer systems take many man-years to design and focuses on planning business computer systems for data processing in the United States. General-purpose computers include the large-scale models such as Sperry-Rand Corporation's Univac II, International Business Machines Corporation's IBM 705, and Radio Corporation of America's Bizmac. With the trend in decentralization, companies are using two types of medium-scale computers, which are classified as magnetic tape input/output and storage or punched cards. Four examples illustrate why companies buy electronic data-processing equipment, including cost savings and faster information processing. Topics are integrated processing, handling paper work and source documents, and rental prices for computers.

The classical process of partitioning an array into subarrays is extended to a more useful array language operation. Various modes of partitioning are defined for different types of arrays, so that subarrays may vary over the original array in a nearly arbitrary manner. These definitions are motivated with several realistic examples to illustrate the value of partitioning for array languages. Of general interest Is the data structure for partitioning. This consists of dynamic tree structures which are used to derive and maintain the array control information. These are described in sufficient detail to be of value In the design of other array languages. The description presented in this paper is Implemented in a new array language, OL/2, currently under development at the University of lllinois. [ABSTRACT FROM AUTHOR]

This paper discusses modularization as a mechanism for improving the flexibility and comprehensibility of a system while allowing the shortening of its development time. The effectiveness of a "modularization" is dependent upon the criteria used in dividing the system into modules. A system design problem is presented and both a conventional and unconventional decomposition are described. It is shown that the unconventional decompositions have distinct advantages for the goals outlined. The criteria used in arriving at the decompositions are discussed. The unconventional decomposition, if implemented with the conventional assumption that a module consists of one or more subroutines, will be less efficient in most cases. An alternative approach to implementation which does not have this effect is sketched. [ABSTRACT FROM AUTHOR]

A cellular array is a two-dimensional, checkerboard type interconnection of identical modules (or cells), where each cell contains a few hits of memory and a small amount of combinational logic, and communicates mainly with its immediate neighbors In the array. The chief computational advantage offered by cellular arrays is the improvement in speed achieved by virtue of the possibilities for parallel processing. In this paper it is shown that cellular arrays are inherently well suited for the solution of many graph problems. For example, the adjacency matrix of a graph is easily mapped onto an array; each matrix element is stored in one cell of the array, and typical row and column operations are readily implemented by simple cell logic. A major challenge in the effective use of cellular arrays for the solution of graph problems is the determination of algorithms that exploit the possibilities for parallelism, especially for problems whose solutions appear to be inherently serial. In particular, several parallelized algorithms are presented for the solution of certain spanning tree, distance, and path problems, with direct applications to wire routing, PERT chart analysis, and the analysis of many types of networks. These algorithms exhibit a computation time that in many cases grows at a rate not exceeding log2, n, where n is the number of nodes in the graph. Straight. forward cellular implementations of the well-known serial algorithms for these problems require about n steps, and noncellular implementations require from n2 to n3 steps. [ABSTRACT FROM AUTHOR]

This paper is concerned with certain aspects of contention for main memory resources in a multiproagrammed computer system operating under demand paging. In the model presented, the number of page- frames of main memory allocated to a problem program varies in time. These changes in memory configuration are represented explicitly in the model, CPU requirements and page exception characteristics of program material being described statistically. Expressions for the distribution of the number of page-frames allocated to an executing program, the long run expected fraction of a program's execution time in a given number of page-frames, and the average execution interval of the multi- programmed load are obtained. It is pointed out heuristically and demonstrated numerically that an increase is obtainable in the average execution interval of the multiprogrammed load over that resulting from equal fixed partitioning of main memory. [ABSTRACT FROM AUTHOR]

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]

Various kinds of interference between communicating parallel processes have been examined by Dijkstra, Knuth and others. Solutions have been given for the mutual exclusion problem and associated subproblems, in the form of parallel programs, and informal proofs of correctness have been given for these solutions. In this paper a system of parallel processes is regarded as a machine which proceeds from one state S (i.e. a collection of pertinent data values and process configurations) to a next state 5' in accordance with a transition rule S ⇒ S . A set of such rules yields sequences of states, which dictate the system's behavior. The mutual exclusion problem and the associated subproblems are formulated as questions of inclusion between sets of states, or of the existence of certain sequences. A mechanical proof procedure is shown, which will either verify (prove the correctness of) or discredit (prove the incorrectness of) an attempted solution, with respect to any of the interference properties. It is shown how to calculate transition rules from the "partial rules" by which the individual processes operate. The formation of partial rules and the calculation of transition rules are both applicable to hardware processes as well as to software processes, and symmetry between processes is not required. [ABSTRACT FROM AUTHOR]

This paper presents an approach to writing specifications for parts of software systems. The main goal is to provide specifications sufficiently precise and complete that other pieces of software can be written to interact with the piece specified without additional information. The secondary goal is to include in the specification no more information than necessary to meet the first goal. The technique is illustrated by means of a variety of examples from a tutorial system. [ABSTRACT FROM AUTHOR]

A sequential pattern recognition (SPR) procedure does not test all the features of a pattern at once. Instead, it selects a feature to be tested. After receiving the result of that test, the procedure either classifies the unknown pattern or selects another feature to be tasted, etc. Medical diagnosis is an example of SPR. In this paper the authors suggest that SPR be viewed as a one-person game played against nature (chance). Virtually all the powerful techniques developed for searching two-person, strictly competitive game trees can easily be incorporated either directly or by analogy into SPR procedures. In particular, one can incorporate the "miniaverage backing-up procedure" and the "gamma procedure," which are the analogues of the minimax backing-up procedure and the alpha-beta procedure," respectively. Some computer simulated experiments in character recognition ore presented. The results indicate that the approach is promising. [ABSTRACT FROM AUTHOR]

With the advent of on-line (time-sharing) computer systems and graphic terminals, we have available a new dimension in numerical problem solving capabilities. Rather than simply use the new power to achieve fast turnaround, we can develop interactive routines which are easy to use and also take advantage of the insight and visual capabilities of the human problem solver. Several on-line systems for general purpose mathematical problem solving have already been implemented as well as some special purpose systems for solving problems in a particular area such as ordinary differential equations. The advantage of restricting the problem area is that the interface with a user can be greatly simplified, in this paper we discuss some of the advantages accrued by such systems and design considerations for interactive routines. Furthermore, an implementation of an on-line least squares data-fitting program, PEG, is presented with results obtained from empirical data. In conclusion, areas for future work in this field are discussed. [ABSTRACT FROM AUTHOR]

Multiprogramming as it is discussed here is a mode of computer operation in which two or more programs are concurrently in processor memory and proceeding, each using the same central processor unit (CPU) and input-output (I/O) channels. These programs are actually proceeding intermittently and singly, according to eligibility (readiness to proceed) and priority. It is useful to be able to represent them as proceeding continuously and simultaneously, each at an effective rate, which may be a fraction of that which it would enjoy in the absence of the other programs. The effective progress rate of each program is sensitive to many detailed characteristics of itself and its co-residents; and simulation has been the best available method of predicting it. This paper presents the results of progress in developing an alternative to simulation, a simulation-tested iterative computation of these rates under certain situations. The algorithm is sensitive to most of the factors that control the phenomenon, including nonquantitative or topological features of the programs' structures. [ABSTRACT FROM AUTHOR]