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Communications of the ACM

Table of Contents


ACM President's Letter: On folk theorems, and folk myths: on folk theorems, and folk myths


A virtual operating system

Moving to a new system is costly and error-prone. The problem can be reduced through use of a virtual operating system that disentangles computing environments from their underlying operating systems. The authors report on their …

An overrelaxation for a numerical inverse of a constant

When division is performed by a power series implementation with additions, subtractions, digit shifts, and multiplications, the convergence rate of the power series is important in practical application. Particularly if the  …

Computer system design using a hierarchical approach to performance evaluation

The concept of a hierarchy of performance models is introduced. It is argued that such a hierarchy should consist of models spanning a wide range of accuracy and cost in order to be a cost-effective tool in the design of computer …

Partial-match retrieval using indexed descriptor files

In this paper we describe a practical method of partial-match retrieval in very large data files. A binary code word, called a descriptor, is associated with each record of the file. These record descriptors are then used to  …

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