Book Nook: The Search for Simplicity Essays in Parallel Programming by Per Brinch Hansen

Abstract

This most recent book of Brinch Hansen is a compilation of twenty-five papers published previously in, among others, Software --Practice & Experience, IEEE Transactions on Software Engineering, Communications of the ACM, Concurrency --Practice & Experience. It covers the whole of his career, from the beginning --he started in 1963 as a systems programmer at the Danish computer company Regnecentralen --up to his current work on computational science, as a professor at Syracuse University. It contains a number of personal recollections and historical reflections, both explicitly --for example in its preface and in papers as "The programmer as a young dog" and "Monitors and Concurrent Pascal: A personal history"--and implicitly, by means of the acknowledgements and references included in each paper. This gives the book a "history of computer-science" as well as an autobiographical character.The main subject of Brinch Hansen's work during the whole of this period has been parallel programming. For a considerable number of years this was directed at the design of operating systems (see, e.g., "The nucleus of a multiprogramming system") and at the reliable and adaptable implementation thereof, by means of high-level programming languages of which Concurrent Pascal has drawn the most attention (see, among others, the abovementioned paper). Since 1988 he has been active in another area, namely the development of parallel programs for the solution of problems in engineering and science (see, e.g., "Model programs for computational science: A programming methodology for multicomputers"). These subjects are dealt with individually and more extensively in his books Operating System Principles (Prentice-Hall, 1973), The Architecture of Concurrent Programs (Prentice-Hall, 1977), and Studies inn Computational Science: Parallel Programming Paradigms (Prentice-Hall, 1995).One might, using a gross simplification, say that Brinch Hansen belongs to the Algol-Pascal school in computer science which has provided such outstanding computer scientists as E.W. Dijkstra, C.A.R. Hoare, E Naur, and N. Wirth. He denotes, in the title of this book, the corresponding line of conduct as a "search for simplicity". This, it seems to me, could better be characterised as: a search for ultimate clarity, precision and elegance combined. The underlying conception is stated in one of Brinch Hansen's favourite maxims: "Programming is the art of writing essays in crystal clear prose and making them execute."Brinch Hansen certainly delivers according to this maxim. His work has been accompanied by the development of high-level programming languages adequate for "crystal clear" and reliable parallel programming: besides Concurrent Pascal, also Edison, Joice and recently SuperPascal. These languages serve both for publication and for implementation purposes. He consequently has also a considerable experience in programming language implementation and compiler development. (Actually, one of his first papers, in BIT vol. 6 no. 1 (1966), dealt with the impleme...