Edsger W. Dijkstra: a Commemoration

This article is a multiauthored portrait of Edsger Wybe Dijkstra that consists of testimonials written by several friends, colleagues, and students of his. It provides unique insights into his personality, working style and habits, and his influence on other computer scientists, as a researcher, teacher, and mentor

A heuristic explanation of Batcher's Baffler

AbstractBatcher's Baffler—so named by David Gries—is a sorting algorithm that is of interest because many of its ‘comparison swaps’ can be executed concurrently. It is also of interest because it used to be hard to explain.This note explains Batcher's Baffler by designing it. Besides including all heuristics, it has two distinguishing features, both contributing to its clarity and brevity: 1.(0) the (little) theory the algorithm relies upon is dealt with in isolation;2.(1) by suitable abstractions, all case analyses have been removed from the argument

Mutual exclusion

Almost all computers today operate as part of a network, where they assist people in coordinating actions. Sometimes what appears to be a single computer is actually a network of cooperating computers; e.g., some supercomputers consist of many processors operating in parallel and exchanging synchronization signals. One of the most fundamental requirements in all these systems is that certain operations be indivisible: the steps of one must not be interleaved with the steps of another. Two approaches were designed to implement this requirement, one based on central locks and the other on distributed order tickets. Practicing scientists and engineers need to come to be familiar with these methods

Edsger Dijkstra. The Man Who Carried Computer Science on His Shoulders

This a biographical essay about Edsger Wybe Dijkstra.Comment: 12 pages. Originally appeared in Inference, Volume 5, Issue 3, 2020, see https://inference-review.com/article/the-man-who-carried-computer-science-on-his-shoulder

Generalizing Morley’s and other theorems with automated realization

A new approach is shown that mechanically proves various theorems in plane geometry by recasting them in terms of constraint satisfaction. A Python 3 implementation called GEOPAR affords transparent proofs of well-known theorems as well as new ones, including a generalization of Morley’s Theorem