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PROFILE venture created to market the Esterel language 2002 Member of the Académie des Sciences 2012 Holder of the “Algorithms, machines and languages” Chair, Collège de France 29 WINTER 2015 N° 36 In those days, methods for programming cyber-physical devices were hampered by the presence of two seemingly conflicting time scales: the physical time at which the process that needs to be controlled operates and the computer’s own calculation speed. Berry took a bold approach by putting himself in an ideal world where calculation times are irrelevant and all reactions are supposed to be instantaneous. “When they write symphonies, composers do not take into account the time needed for the sound of the instruments to reach the listeners’ ears,” this music enthusiast explains. “Esterel is based on the same principle.” The world of research seemed somewhat dubious, and with good reason: in the 1980s, computers were 200 times slower than they are today. But, because of its simplicity, clarity, and implantation efficiency, a number of manufacturers showed a keen interest in this programming language for real-time systems. French aircraft manufacturer Dassault, to start with, saw it as a way to expand the limited possibilities of automatic control and computerize the instrument panels of its Rafale jet fighters. Moreover, Esterel gave the company another significant advantage: the formal verifications performed while writing the program make the resulting systems more secure. In addition to the aeronautics industry, which gradually adopted embedded systems for all aircraft functions (automatic pilot, braking, air conditioning, etc.), other users Five Key Dates 1970 Researcher at the École des Mines and Inria, Paris 1977 Senior researcher at the École des Mines, Sophia-Antipolis 2001-2009 Scientific director of Esterel Technologies, a corporate of so-called critical IT systems—telecommunication protocols, nuclear power plants, robotics, etc.—also became early adopters. The Esterel Technologies company was founded in 2000 to market the Esterel programming language, and Berry served as its scientific director from 2001 to 2009. The firm’s client portfolio included Dassault and electrical systems specialist Thales, but also semiconductor giants Intel, Texas Instruments, and ST Microelectronics. One of the company’s earliest developments was a special version of Esterel for designing electronic circuits. “We were very fortunate to work with such scientifically-advanced manufacturers,” Berry says. “The problems we had to solve for them were much more complex than our laboratory hypotheses.” A remarkable teacher Today, Berry devotes most of his energy to preparing his lectures at the Collège de France—not so different a task, he says, from his teaching experience at Les Pouces Verts, a Montessori school near Sophia-Antipolis where he spent several years teaching computer classes for young children. And he is not done with programming languages either. The boom in Internet use and the rampant proliferation of mobile apps have pushed him in a new direction: in collaboration with Inria researcher Manuel Serrano, Berry is developing HipHop, a language aimed at facilitating communication with connected objects. He is also working with IRCAM on the transposition of Esterel to the world of electronic music and the development of algorithmic scores. Despite a hectic schedule, this father and stepfather of three adult children still finds the time to enjoy his stepdaughter’s acrobatic prowess as a circus performer. The pioneer of synchronous languages and computer science magician seems to have unlocked the secrets of time. ii © C. FRÉSILLON/CNRS PHOTOTHÈQUE gerard.berry@college-de-france.fr A video interview of Gérard Berry is available online: www.cnrs.fr/cnrsmagazine


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