C CERN 81-03 -L 12 March 1981 P00025641 ORGANISATION EUROPÉENNE POUR LA RECHERCHE NUCLÉAIRE CERN EUROPtiAN ORGANIZATION FOR NUCLEAR RESEARCH PROCEEDINGS OF THE 1980 CERN SCHOOL OF COMPUTING Vraona-Attiki, Greece, 14-27 September 1980 GENEVA 1981 © Copyright CERN, Genève, 1981 Propriété littéraire et scientifique réservée pour Literary and scientific copyrights reserved in tous les pays du monde. Ce document ne peut all countries of the world This report, or eue reproduit ou traduit en luut ou en partie any part of It, may not be reprinted or trans­ sans l'autorisation écrite du Directeur général lated without written permission of the du CERN, titulaire du droit d'auteur. Dans copyright holder, the Dtrector-<Jeneral of les eus appropries, et s'il s'agit d'utiliser le CERN. However, permission will be freely document à des fins non commerciales, celte granted for appropriate non-commercial use. autorisation sera volontiers accordée, If any patentable invention or registrable l.e CERN ne revendique pas ta propriété des design is described in the report, CERN makes inventions brevetâmes et dessins ou modèles no claim to property rights in ii hut offers it susceptibles de dépôt qui pourraient être décrits for the free use of research institutions, manu­ dans le present document; ceux-ci peuvent être facturers and olhers. CERN, however, may librement utilises par les instituts de recherche, oppose any attempt by a user to claim any les industriels et autres intéressés. Cependant, proprietary or patent rights in such invention» If CERN se réserve le droit de s'opposer à or designs as may be described in the present toute revendication qu'un usager pourrait faire document. de la propriété scientifique ou industrielle de toute: invention ci tout dessin ou modèle dé­ crits dans le présent document. CERN 81-03 12 March 1981 ORGANISATION EUROPÉENNE POUR LA RECHERCHE NUCLÉAIRE CERN EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH PROCEEDINGS OF THE J.980 CERN SCHOOL OF COMPUTING Vraona-Attiki, Greece, 14-27 September 1980 GENEVA 198.1 CBRN - Service d'information scientifique - RD/486 - 2300 - mars 1981 -m - ABSTRACT The sixth CERN School of Computing held in September 1980 covered a range of subjects related to computing in high-energy physics. These Proceedings contain notes of lectures on methods in numerical approxima­ tion, on the statistical significance of experimental data, and on synibolic computation and its application to high-energy physics. Two lectures covered data analysis for electronic experiments and for bubble chamber and hybrid experiments, respectively. Aspects of on-line computing and the underlying microprocessor technology were treated in lectures on the use of intelligent devices in high-energy physics experiments, on micro­ programming and bit-slice technology, and on software tools for microprocessor-based systems. Another lecture covered practical data acquisition problems. These proceedings also contain lecture notes on fault-tolerant computing systems and on technological advancements in computer systems and networks. - IV - - V - PREFACE The 1980 CERN School of Computing, the sixth in the series, took place in Vraona, Greece, from 14 to 27 September 1980. Sixty-one students parti ciliated, fifteen from Greece, the rest from the other Member States of CERN. The large majority of the participants were ivorking in data handling for high-energy physics; only a few were active in other applica­ tions of computing. The lectures covered a wide range of subjects, from numerical approximation methods and symbolic computation to fault-tolerant computing. A large part of the lecture programme was dedicated to topics of immediate interest to experimentation in high-energy physics: data analysis teclini.ques and problems in data acquisition and on-line computing. Very important aspects of modern technology were reviewed in lectures on computer systems and networks, on microprogramming and bit slices, and on software tools for microprocessors. Judging by the exceptionally high attendance at most of the lectures, the programme apparently corresponded to the interests of the majority of the participants. The School was opened by the Director of the Hellenic Agency for Research and Development, Dr. G. Argyropoulos. The Agency and the Ministry of Co-ordination provided a generous finan­ cial contribution to the School. A press conference was organized at the Agency for Research and Development with the aim of informing a wider public about the activities of CRRN and the significance of the School. On behalf of the Advisory Committee and all the participants, we wish to express our gratitude to our Greek colleagues who took care of the local organization. In particular our very warm thanks go to Prof. G. Philokyprou, who spared no time and effort to solve all the problems of the local organization. The ground had been prepared already by the efforts of Prof. Th. G. Kouyoumzelis, who had spread the necessary enthusiasm throughout scientific and governmental circles. Our most sincere thanks are extended to him. We are also grateful to NRC Demokritos and the University of Athens for technical assistance. The many aspects of the preparation and running of the School were taken care of by Mrs. Ingrid Barnett, of the CF.RN Scientific Conference Secretariat, who arranged matters with her usual competence. In Greece she was enthusiastically assisted by Mrs. Alexandra Demetriou-Kouyoumzelis and Miss Roula Prassianakis. It is a pleasure to thank them for their efforts. The lecturers, whose interesting talks and good spirits were essentia] to the success of the School, are sincerely thanked for their work in preparing, delivering, and documenting their lectures, and for their active participation in the life of the School. We would also like to extend our appreciation to those members of the Q:RN Publications Group who worked together to produce these Proceedings. Finally, we must thank the manager of the Vraona Bay Hotel, Mr. Cherouvim, and his staff, whose good will and effort made our stay a memorable one. The lecture programme, the sun, the beautiful site, the recreational facilities, and the enthusiasm of the participants all contributed to making the 1980 CERN School of Computing most successful. It will be remembered for a long time by everyone. C. Verkerk, Editor ;V A ADVISORY COMMITTEE A.NAGNO.STOPOULOS, T. Ministry of Coordination, Athena, Greene GABATHULER, E. CERN, Geneva, Switzerland KOUyoUMKELIS, Th.G. National Technical University, Athens, Greece (Hon.President) LOCK, w.o. CERN, Geneva, Switzerland MACLEOD, G.R. CERN, Geneva, Switzerland MERMIKIDES, M.E. NRC "Demokritoe", Aghia Paraskevi, Greece *) PHILOKYPROU, G. University of Athens, Greece (Joint Director of the School) VERKERK, C. CERN, Geneva, Switzerland (Scientific Secretary) ZACHAROV, v. University of London Computer Centre, U.K. (Chairman and Joint Director of the School) *) ZANELLA, P. CERN, Geneva, Switzerland BARNETT, I. CERN, Geneva, Switzerland (Organising Secretary) *) Current address: CERN, Geneva, Switzerland. - VI L - CONTENTS PREFACE v INTRODUCTORY TALK I V, ZachaPO'O COMPUTER SYSTEMS AND NETWORKS: STATUS AND PERSPECTIVES 8 V. Zaahapov SURVEY OF METHODS OF NUMERICAL APPROXIMATION 78 R,F. Churchhov.se DATA ANALYSIS FOR BUBBLE CHAMBER AND HYBRID SYSTEMS 106 M.E. Mermikides DATA ANALYSIS FOR ELECTRONIC EXPERIMENTS 136 //. Grote DETERMINING THE STATISTICAI,, SIGNIFICANCE OF EXPERIMENTAL RESULTS 182 F. J cone e INTRODUCTION TO BIT-SLICES AND MICROPROGRAMMING 220 A. Van Dam SOFTWARE TOOLS FOR MICROPROCESSOR BASED SYSTEMS 241 C. Halatsis USE OF INTELLIGENT DEVICES IN HIGH-ENERGY PHYSICS EXPERIMENTS 282 C. Verkerk PRACTICAL DATA-ACQUISITION PROBLEMS IN LARGE HIGH-ENERGY PHYSICS EXPERIMENTS 325 R. W, Dobinson FAULT TOLERANT COMPUTING SYSTEMS 362 B. Randall SYMBOLIC COMPUTATION AND ITS APPLICATION TO HIGH-ENERGY PHYSICS 390 A.C. Beam LIST OF PARTICIPANTS 407 INTRODUCTORY TALK V. Zacharov*) University of London Computer Centre, United Kingdom It is my very great pleasure indeed to say a few words to introduce the 19B0 CERN School of Computing and data processing. And it is particularly pleasing to be able to do so in such a fine setting - Vraona in the Attic peninsula. Let me welcome all the participants, students, faculty and our assistants to the school. This school is the sixth in a biennial series which started in 1970, and it is complementary in some ways to the more extended series of CERN Summer Schools in Physics. The origin of the Computing School stemmed from the realization that computers and computing had become an insubtractable part of elementary-particle physics studies, that those engaged in physics needed to know quite a lot about computers as a tool, and that the computer experts involved closely with the computer systems themselves needed to understand the nature of the physics problems in order to apply these systems more effectively. In short, as in so many other fields of science, there need to be an inter-disciplinary interaction and exchange. The primary motivation of the School was thus to improve and increase the awareness of those engaged in computing and data-processing within high-energy physics of both scientific problems and the computing tools available to solve them. There was however a secondary motivation: this was to bring to the attention of those others, not necessarily engaged directly in high-energy physics, some of the results and indeed excitement of developments in that field. In this way, it was hoped, young applied mathematicians and computer scientists might become involved in helping to solve some of the outstanding computational problems arising in particle physics. For this reason, at the School, we have both physicists and computer specialists among the students. And for this reason we have representatives of both these fields among the lecturers. It is not surprising, bearing in mind the aims of the CERN School, that the range of topics covered should be somewhat broader than the range of computational activities at a high-energy physics centre. And this is an excellent practice, not only because this is after all a school, with an intrinsic need for more completeness and generality, but also because of the future.