Theory
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COBOL (COmmon Business Oriented Language) is an English Language programming system which is capable of being implemented on a wide variety of electronic digital computers for use in the solution of business data processing problems.
The idea was conceived in May, 1959 at a meeting called in the Pentagon by Mr. Charles Phillips of the Office of the Assistant Secretary of Defense, Comptroller. The purpose of this meeting was to consider the desirability and the feasibility of establishing a common language for the programming of electronic computers for data processing. Representatives from computer user installations, both government and industrial, computer manufacturers, universities, and others concerned with computers were present. There was almost unanimous agreement that the project was both desirable and feasible. The COnference on DAta SYstems Languages (CODASYL) was established, and three committees were defined and staffed. These committees were the Short Range Committee, the Intermediate Range Committee, and the Long Range Committee. Each committee had its own goal and its own time scale. The coordination of the work to be performed was to be accomplished by an Executive Committee.
This note describes a rational approximation for the error function which has been found useful in a subroutine as an asymptotic expression of improved accuracy. While the method of the approximation is along well-established lines [1, 2, 3, 4] a brief description may be of interest since the feasibility of a simplified means of determining the basic coefficients is shown for the error function, and this technique may be useful in other cases.
A generalized polyphase merge algorithm
The k-generalized Fibonacci numbers are defined as in [1]. A polyphase merge (merging an equal number of sequences from k tapes onto a single unused tape) using k+1 tapes is defined in terms of linear combinations of these numbers. A method is described to output sequences onto k of k+1 tapes after the internal sorting of elements to form sequences. This method will permit a polyphase merge of sequences of sorted elements provided that enough sequences are generated internally to place the proper numbers of sequences on each of the k tapes. For each value of k, there is a set of permissible numbers that can represent the total number of sequences generated during the original output process. If one of these numbers is met exactly and if there is a specific distribution of sequences on the k tapes, then a polyphase merge may proceed. If these conditions are not met, an algorithm is necessary to adjust the numbers of sequences to permit a polyphase merge. This paper describes such an algorithm.
The suggestions in this paper are part of the terminology used in work for the University of Pennsylvania's Office of Computer Research and Education. The work is jointly supported by the National Science Foundation* and the Air Force Office of Scientific Research.†
An algorithm for equivalence declarations
Many algebraic translators provide the programmer with a limited ability to allocate storage. Of course one of the most desirable features of these translators is the extent to which they remove the burden of storage allocation from the programmer. Nevertheless, there are situations in which one wishes to make certain vectors and arrays contiguous, coincident, or overlapping. This is made possible in FORTRAN by the use of COMMON and EQUIVALENCE statements, in MAD by the use of PROGRAM COMMON, ERASABLE, and EQUIVALENCE statements, etc.
Operational compatability of systems—conventions
This project is engaged in (a) a program of research into the application of the concepts and techniques of modern data processing to the design of mechanical parts, and (b) the further development of automatic programming systems for numerically controlled machine tools. The project is a cooperative venture between the Computer Applications Group of the Electronic Systems Laboratory and the Design and Graphics Division of the Mechanical Engineering Department, and is sponsored by the Manufacturing Methods Division of the USAF Air Material Command through Contract AF-33(600)-40604.
Logic tables are an excellent way of developing and expressing the logic required in procedures, operations, systems and circuits. A set of rules for writing and using logic tables is explained by means of some simple examples. Then the logic structure of a vending machine is given in which two logic tables are used. Logic tables are two-dimensional in nature, enabling us to fully express and consider both the sequential and parallel aspects of logic. They can be compiled directly into a computer program and so eliminate the need for flow charting and hand coding.
The ALGOL 60 Report,* when first encountered, seems to describe a very complex language which will be difficult to learn. The “metalinguistic formulae” admirably serve the purpose of precisely specifying a language, but they are certainly not very readable for a beginner. However, experience has shown that once the report is explained it is in fact easy to learn ALGOL and to write algorithms in it. The language is so general and powerful it can handle an enormous class of problems.
It is not hard to learn those parts of ALGOL present in other compiler languages: how to write assignment and go to and for statements, etc. Indeed, a lot of the unnecessary restrictions imposed by other compiling languages have finally been lifted. But ALGOL also allows many unobvious things to be written, as we will see later, and herein lies a problem: ALGOL seems to have become too general. So many restrictions have been lifted that a lot of technical details crop up which are hard to learn and to use correctly. In this paper some of the more obscure features of the language are considered and their usefulness is discussed. Remarks are based on the authors' interpretations of the ALGOL 60 Report.
An indirect chaining method for addressing on secondary keys
Methods for entering random-access files on the basis of one key are briefly surveyed. The widely used chaining method, based on a pseudo-random key transformation, is reviewed in more detail. An efficient generalization of the chaining method which permits recovery on additional keys is then presented.
Comparison of iterative methods for the calculation of nth roots
Three iterative methods for calculation of nth roots (including one proposed by the author) are compared in two ways: (1) Theoretical convergence estimates are given. (2) A new macro-compiler which estimates machine running time is used to compare the running time of the three methods for a variety of input data.
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