Pascal Plus, Mesa, SB-Mod, Concurrent Euclid, Pascalc, Concurrent C, Emerald, Real-time Euclid, Pascal-FC, Turing Plus, Predula. Concurrent Pascal was the first concurrent programming language: the first language developed specifically for concurrent programming, and more importantly, the first language to demonstrate that it was possible to incorporate secure, high-level facilities for concurrency, where the system could guarantee that processes access disjoint sets of variables only and do not interfere with each other in time dependent ways. Hoare described it as "an outstanding example of the best of academic research in this area." Source and portable code for Concurrent Pascal and the Solo operating system were distributed to at least 75 companies and 100 universities in 21 countries, resulting in its widespread adoption, porting and adaptation in both industry and academia. Greg Andrews observed that Concurrent Pascal and monitors "greatly influenced most subsequent concurrent language proposals." Brinch Hansen's The Architecture of Concurrent Programs was the first book on concurrent programming, and was eventually published in three languages (English, Japanese, and German). More than a dozen years after its publication, P. J. Plauger observed: In 2005, ACM members voted The Architecture of Concurrent Programs a top 25 classic book, ranking it 18th in the survey, and appearing on 8% of ballots. It is now available from the ACM Digital Library. Distributed computing and remote procedure call Remote procedure calls used in modern operating systems trace their roots back to the RC 4000 multiprogramming system, which used a request-response communication protocol for process synchronization. In his 1978 paper on distributed processes, Brinch Hansen proposed a language for distributed computing based on external requests consisting of procedure calls between processes. This later became known in an operating system context as the remote procedure call. Later, Brinch Hansen developed two languages extending Hoare's CSP message-passing paradigm with parallel recursion, and showed how to efficiently implement such. Honors and awards Doctor Technices, Technical University of Denmark, for The Architecture of Concurrent Programs, 1978 First Henry Salvatori Professor of Computer Science, University of Southern California, 1982 IEEE Fellow, 1985 Distinguished Professor, Syracuse University, 1987 Chancellor's Medal, Syracuse University, 1989 IEEE Computer Pioneer Award, for pioneering development in operating systems and concurrent programming exemplified by work on the RC 4000 multiprogramming system, monitors, and Concurrent Pascal, 2002 Programming languages Concurrent Pascal (1975) Distributed Processes (1978) Edison (1981) Joyce (1987) SuperPascal (1993) Quotations Writing is a rigorous test of simplicity: