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Communications of the ACM

Table of Contents


Letters to the editor


From the president of ACM


Optimizers: their structure


Survey of punched card codes

The “Survey of Coded Character Representation” by R. W. Bemer (p. 639) covers the representation of symbols in paper tape, magnetic tape and main storage of a number of different machine systems. Another method of mechanical  …

Survey of coded character representation

Technical Committee 97 of the International Standards Organization (ISO) is concerned with standards in data processing. The American Standards Association holds the secretariat of this committee. Sectional Committee X3 of A.S …

Algorithm 30: numerical solution of the polynomial equation


On programming the numerical solution of polynomial equations

Numerical techniques are presented for computing the roots of polynomial equations. By applying the recommended scaling and inversion rules, the basic Bistrow and Newton-Raphson iterative techniques can be applied with great  …

Fibonaccian searching


A note on approximating ex

In reference to the discussion about evaluation ex on page 500 of the September Communications of the ACM, may I point out that there is no need to use Mr. Berin's lengthy expressions to obtain relation (9). If we use the simple …

Multiple precision arithmetic


A method for overlapping and erasure of lists

An important property of the Newell Shaw-Simon scheme for computer storage of lists is that data having multiple occurrences need not be stored at more than one place in the computer. That is, lists may be “overlapped.” Unfortunately …

Two methods for word conversion on the IBM 709: method 2


Two methods for word inversion on the IBM 709: method 1

In some logical problems it is necessary or convenient to invert the bit structure of a word, i.e., replace bit i by bit n + 1 - i for i = 1, 2, ···, n, thus creating a mirror image. The method described here exploits the CAQ …

Digital simulation of discrete flow systems0

The discrete flow systems discussed are characterized by the movement of randomly arriving items along interacting channels. Programming a digital computer to simulate such systems utilizes some techniques not common in other …

COPE (Console Operator Proficiency Examination)

Each year electronic computers become more sophisticated, and the programs they must process become more complex. Because of this, dependence of those in computing on the skill and experience of operators is increasing. At the …

A comparison of 650 programming methods

An evaluation of an automatic programming method can be made from many points of view. Two recent articles give evaluations of two compilers for the IBM 650 based on the method of decomposition of compiler statements into machine …