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Communications of the ACM

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ACM president's letter: education, certification, and the CDP exam


Monitors: an operating system structuring concept

This paper develops Brinch-Hansen's concept of a monitor as a method of structuring an operating system. It introduces a form of synchronization, describes a possible method of implementation in terms of semaphores and gives  …

A weighted buddy method for dynamic storage allocation

An extension of the buddy method, called the weighted buddy method, for dynamic storage allocation is presented. The weighted buddy method allows block sizes of 2k and 3·2k, whereas the original buddy method allowed only block …

A note on the calculation of average working set size

Finite-length reference string of arbitrary structure are considered, and an exact expression for average working set size in terms of “corrected” interreference interval statistics is derived. An example is discussed; upper  …

Structured data structures

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 …

A back-end computer for data base management

It is proposed that the data base management function be placed on a dedicated back-end computer which accepts commands (in a relatively high level language such as the CODASYL Data Base Task Group, April 1971 Report) from a  …

On generation of test problems for linear programming codes

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 …

Algorithm 486: Numerical inversion of Laplace transform [D5]

This work forms part of a thesis presented in Grenoble in March 1972. Improvements made to the Dubner and Abate algorithm for numerical inversion of the Laplace transform [1] have led to results which compare favorably with theirs …

A computer routine for quadratic and linear programming problems


Enumerating full-time programmers

Data from the 1970 Census and the Department of Labor's Area Wage Surveys are used to derive estimates of the number of full-time programmers employed during the years 1969 through 1973. The 1973 figure of 180,000 is considerably …

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