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Communications of the ACM

Table of Contents


ACM President's Letter: ACM and legal issues


On the construction of a representative synthetic workload

A general method of constructing a drive workload representative of a real workload is described. The real workload is characterized by its demands on the various system resources. These characteristics of the real workload are …

Dynamic memory repacking

A probabilistic model of a multiprogramming system is exercised in order to determine the conditions under which the dynamic repacking of main memory is beneficial. An expression is derived for the maximum interference that a …

Optimal space allocation on disk storage devices

When the amount of space required for file storage exceeds the amount which can be kept online, decisions must be made as to which files are to be permanently resident and which mountable. These decisions will affect the number …

Some performance tests of “quicksort” and descendants

Detailed performance evaluations are presented for six ACM algorithms: quicksort (No. 64), Shellsort (No. 201), stringsort (No. 207), “TREESORT3” (No. 245), quickersort (No. 271), and qsort (No. 402). Algorithms 271 and 402 are …

Visible surface plotting program


Algorithm 475: Visible Surface Plotting Program


Scan conversion algorithms for a cell organized raster display

Raster scan computer graphics with “real time” character generators have previously been limited to alphanumeric characters. A display has been described which extends the capabilities of this organization to include general  …

Emotional content considered dangerous

I had hoped that Moorer's rebuttal to my short communication in the November 1972 Communications would close the debate on a topic which, like the computer itself, has provoked an inordinately large quantity of unqualified argument …

Quadratic search for hash tables of sizes P n

It has previously been claimed [1 and 2] that the quadratic hash table search method of Maurer cannot usefully be applied to tables of size 2n. This is not so; the method can in fact be applied to tables of size pn for any prime …

A note on a combinatorial problem of Burnett and Coffman


Efficient implementation of a variable projection algorithm for nonlinear least squares problems

Nonlinear least squares problems frequently arise for which the variables to be solved for can be separated into a linear and a nonlinear part. A variable projection algorithm has been developed recently which is designed to  …

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