Howard Barringer: the Man who Invented the Past

This article is an introduction to Professor Howard Barringer, in honor of his 60th birthday on December 20, 2011, which was celebrated by the HOWARD-60 workshop (Higher-Order Workshop on Automated Runtime verification and Debugging), held on the same day at University of Manchester. 1 A 60 Second Overview Howard Barringer was born on December 20, 1951, is married to Margaret, and has three children. This forms the concrete part of Howard’s life. Beyond this, Howard has had an abstract life centred around mathematics, physics, and computer science. At secondary school (1964-1969) Howard moved into the science stream and finished with ’A’ levels in mathematics (pure and applied) and physics. He went on to University of Manchester where he first received a B.Sc in Physics (1972), then an M.Sc in Computer Science (1973), and finally a Ph.D in Computer Science (1978). His adult academic life has been centred at University of Manchester. He became a Research Associate in Computer Science at Manchester in 1975, a Lecturer in 1977, a Senior Lecturer in 1986 and was then rapidly promoted to Professor in Computer Science in 1987. For the majority of his career, his research and teaching has been focussed around the development and application of logics, in particular temporal and modal logics, in the specification, design, and analysis of software and hardware systems. Howard insisted on the importance of past time logic in temporal logic, and hence got named “the man who invented the past”. He has taught classes in the theory of computation, compiling techniques, specification and verification, concurrency, modal and temporal logic, algorithms, and programming in Java. Howard also spent a significant portion of his career in senior and highly influential administrative positions at University of Manchester. He has been invited to present over 100 seminars and research lectures in Austria, Belgium, Canada, China (Beijing, Shanghai, Wuhan), Denmark, England, France, Germany, Greece, Israel, Italy, the Netherlands, Norway, Scotland, South Africa, Spain, Sweden, USA (Arizona, California, New York, Pennsylvania, Texas) and Wales. He was visiting professor at Kings College (2001 and 2006), and visited Silicon Valley numerous times including NASA Ames Research Center, Moffett Field, CA in 2002 and 2003, and the Computer Science Laboratory at SRI International, Menlo Park, CA in 2002. It has been observed that, temporally speaking, a series of Mars Rovers were launched after Howard visited NASA. Howard was one of the ∗The writing of this article was carried out at Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. 1This title was assigned to Howard in connection with his 60th birthday by Andrei Voronkov. A. Voronkov, M. Korovina (eds.), HOWARD-60, pp. 1–12 1 Howard Barringer Klaus Havelund founding editors of the Journal of Logic and Computation in 1989 and is now Co-Chief Editor with Dov Gabbay. He is also Editor for Journal of Applied Logic. 2 Initial Research Phase Howard started his research activities in systems programming (1973–1979). The research for the M.Sc and Ph.D degrees was concerned with compiling techniques for the ALGOL 68 programming language. As a Research Assistant after his doctorate, his work involved the design and implementation of portable compiling systems, and resulted in a low-level target machine language (TML) (Barringer, Capon and Phillips, 1979) [20] and a simpler high-level systems implementation language (MUPL). This line of work continued during the first year in which he was employed as a lecturer within the Department of Computer Science and resulted in the implementation of an improved, higher level, intermediate target language (TL) that enabled straightforward implementation of an improved systems implementation languages (MUSL). During the end of the 1970s, Howard developed an interest in formal methods, causing a change of direction. This change coincided with Cliff Jones joining Manchester University as professor. Together with Howard’s Ph.D student Jen Cheng they worked on a logic for partial functions, see (Barringer, Cheng and Jones, 1984) [22]. During the first half of the 1980ties, his interest otherwise centred around compositional temporal logic, specifically techniques for specification and verification of parallel and distributed systems. Initially, results were obtained for the axiomatic verification of Ada tasks (Barringer and Mearns, 1982) [21] and (Barringer and Mearns, 1986) [23]. He became a member of the CEC Ada-Europe Working Group on Formal methods for Specification and Development (1983–1985), was chairman for this group from 1985–88, and was additionally member of the Ada UK Working Group on Formal Methods from 1984–87. In 1981-1982 he went on two three-week trips to 12 university and industrial research laboratories in the United States to have discussions with researchers about their verification methods. The research undertaken was published as a volume in the Springer-Verlag Lecture Notes in Computer Science series (Barringer, 1985) [1]. The study led to ideas on specifying systems in a modular and compositional fashion based on the use of temporal logics – including reasoning about the past – which were presented in (Barringer and Kuiper, 1983) [44]. As a result of this work, Howard spent a couple of weeks at the Weizmann Institute of Science, Israel, at the invitation of Professor Amir Pnueli in order to collaborate on developing compositional temporal proof systems for parallel languages (the goal of compositionality in temporal proof systems had been standing for approximately eight years). That visit marked the beginning of a strong collaboration with Pnueli, leading to general techniques for constructing compositional temporal proof systems for both shared variable and message based communication mechanisms in parallel programming languages (Barringer, Kuiper and Pnueli, 1984) [47], (Barringer, Kuiper and Pnueli, 1985) [49] and for fully abstract concurrency models (Barringer, Kuiper and Pnueli, 1986) [50]. Other researchers joined the work and visited Manchester, including Professors Willem-Paul de Roever and Zhou Chaochen. In 1986, at the invitation of Professor Zhou Chaochen, he presented a research lecture series on temporal logic and its applications in concurrency (a total of 32 hours of lectures was presented at the Academy of Sciences, Beijing, Wuhan University and Fudan University, Shanghai, over a four week period). Further work led, for example, to a temporal fixed point calculus (Banieqbal and Barringer, 1986) [104], as well as what was probably the first practical implementation of a decision procedure for checking validity of a linear temporal logic covering infinite past, present and infinite