- Email: [email protected]
Parallel computing
183
Guest editorial
Parallel computing The PARLE Conference is a meeting place where every two years researchers from industry and academia exchange their views on parallel computing. It is sponsored by the ESPRIT programme of the Commission of the European Communities. This special issue of Future of Generation Computer Systems is a selection of eight contributions to the PARLE '89 Conference, which was held in Eindhoven, The Netherlands, in June 1989. After the conference the papers were edited by the authors to reflect the latest developments in the research reported. Our selection opens with a contribution by A.J.G. Hey in which he gives an overview of computational models and programming paradigms for parallel machines. He addresses in particular the commercial prospects for general purpose parallel machines. Next come a few contributions in which different programming environments are explored with respect to their potential for parallel computing. B.K. Livezey and R.R. Muntz discuss in their article about ASPEN the use of a stream-oriented program notation. ASPEN programs can be annotated to have the programmer control the degree of parallelism and the load balancing. The LADY programming environment, presented by D. Wybranietz and P. Buhler, is an object-oriented program notation aimed at designing system software for parallel machines. It incorporates dynamic creation and annihilation of objects. The paper by D. Bolton et a/. proposes a mixed approach of graph reduction and object-oriented programming. The former approach is used at the level of requirements and specifications. The object-oriented notation is used to implement the computation as a system of communicating processes. As an example architecture they
discuss the COBWEB machine, which is also the subject of the paper by P. Anderson et aL The COBWEB is targeted at parallel executions of functional programs. They show how this machine can be realized on a single, large wafer of semiconductor. The next paper deals with shared-memory machines. Large machines of this type have the tendency to suffer from bottlenecks associated with the interlocking mechanism and access to shared memory. R. Gupta and M. Epstein propose to alleviate this problem by introducing a new synchronization mechanism for processors: the fuzzy barrier. This mechanism is intended to reduce the synchronization overhead in shared-memory machines. The last two papers address formal models of parallel computing. They have been selected because they both show how simple theories can be employed to model properties of parallel computations in an elegant way. J. Parrow introduces a simple algebra, which turns out to be very expressive for describing and analysing systems of synchronously communicating processes. F.S. de Boer shows how a simple form of temporal logic can be used to specify communicating processes. We are most grateful to the authors who, by editing and updating their contributions to the PARLE '89 Conference, have made it possible to present the readers of Future Generation Computer Systems this state-of-the-art insight in parallel computing.
North-Holland Future Generation Computer Systems 6 (1990) 183 0376-5075/90/$03.50 © 1990 - Elsevier Science Publishers B.V. (North-Holland)
Eddy Odijk Philips Research Martin Rem Eindhoven University of Technology
Guest editorial
Parallel computing The PARLE Conference is a meeting place where every two years researchers from industry and academia exchange their views on parallel computing. It is sponsored by the ESPRIT programme of the Commission of the European Communities. This special issue of Future of Generation Computer Systems is a selection of eight contributions to the PARLE '89 Conference, which was held in Eindhoven, The Netherlands, in June 1989. After the conference the papers were edited by the authors to reflect the latest developments in the research reported. Our selection opens with a contribution by A.J.G. Hey in which he gives an overview of computational models and programming paradigms for parallel machines. He addresses in particular the commercial prospects for general purpose parallel machines. Next come a few contributions in which different programming environments are explored with respect to their potential for parallel computing. B.K. Livezey and R.R. Muntz discuss in their article about ASPEN the use of a stream-oriented program notation. ASPEN programs can be annotated to have the programmer control the degree of parallelism and the load balancing. The LADY programming environment, presented by D. Wybranietz and P. Buhler, is an object-oriented program notation aimed at designing system software for parallel machines. It incorporates dynamic creation and annihilation of objects. The paper by D. Bolton et a/. proposes a mixed approach of graph reduction and object-oriented programming. The former approach is used at the level of requirements and specifications. The object-oriented notation is used to implement the computation as a system of communicating processes. As an example architecture they
discuss the COBWEB machine, which is also the subject of the paper by P. Anderson et aL The COBWEB is targeted at parallel executions of functional programs. They show how this machine can be realized on a single, large wafer of semiconductor. The next paper deals with shared-memory machines. Large machines of this type have the tendency to suffer from bottlenecks associated with the interlocking mechanism and access to shared memory. R. Gupta and M. Epstein propose to alleviate this problem by introducing a new synchronization mechanism for processors: the fuzzy barrier. This mechanism is intended to reduce the synchronization overhead in shared-memory machines. The last two papers address formal models of parallel computing. They have been selected because they both show how simple theories can be employed to model properties of parallel computations in an elegant way. J. Parrow introduces a simple algebra, which turns out to be very expressive for describing and analysing systems of synchronously communicating processes. F.S. de Boer shows how a simple form of temporal logic can be used to specify communicating processes. We are most grateful to the authors who, by editing and updating their contributions to the PARLE '89 Conference, have made it possible to present the readers of Future Generation Computer Systems this state-of-the-art insight in parallel computing.
North-Holland Future Generation Computer Systems 6 (1990) 183 0376-5075/90/$03.50 © 1990 - Elsevier Science Publishers B.V. (North-Holland)
Eddy Odijk Philips Research Martin Rem Eindhoven University of Technology