ORGANISATION EUROPEENNE POUR LA RECHERCHE NUCLEAIRE CERN EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH 1992 CERN SCHOOL OF COMPUTING Scuola Superiore G. Reiss Romoli, L'Aquila, Italy 30 August-12 September 1992 PROCEEDINGS Editor: C. Verkerk GENEVA 1993 © Copyright CERN, Genève, 1993 Propriété littéraire et scientifique réservée Literary and scientific copyrights reserved in pour tous les paya < 11» inonde. Ce document ne all countries of the world. This report, or peut être reproduit ou traduit en tout ou en any part of it. may not be reprinted or trans­ partie sans l'autorisation écrite du Directeur lated without written permission ol the copy­ général du CERN, titulaire du droit d'auteur. right holder, the Director-General of CERN. Dans les cas appropriés, et s'il s'agit d'utiliser However, permission will be freely granted for le document à des fins non commerciales, cette appropriate non-commercial use. autorisation sera volontiers accordée. If any patentable invention or registrable Le CERN ne revendique pas la propriété des design is described in the report. CERN makes inventions brevetables et dessins ou modèles no claim to property rights in it but offers i( susceptibles de dépôt qui pourraient être for the free use of research institutions, man­ décrits dans le présent document ; ceux-ci peu­ ufacturers and others. CERN, however, may vent être librement utilisés par les instituts de oppose any attempt by a user to claim any recherche, les industriels et autres intéressés. proprietary or patent rights in such inventions Cependant, le CERN se réserve le droit de or designs as may be described in the present s'opposer à toute revendication qu'un usager document. pourrait faire de la propriété scientifique ou industrielle de toute invention et tout dessin OU modèle décrits dans le présent document. ISSN 0007-8328 ISBN 92-9083-052-20 CERN 93-03 6 July 1993 ORGANISATION EUROPÉENNE POUR LA RECHERCHE NUCLEAIRE CERN EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH 1992 CERN SCHOOL OF COMPUTING Scuola Superiore G. Reiss Romoli, L'Aquila, Italy 30 August-12 September 1992 PROCEEDINGS Editor: C Verkerk GENEVA 1993 CERN-Service d'information scientifique-RD/907-2200~juiHet 1993 Abstract These Proceedings contain written accounts of most of the lectures given at the 1992 CERN School of Computing, covering a variety of topics. A number of aspects of parallel and of distributed computing were treated in five lecture series: "Status of parallel computing", "An introduc­ tion to the APE100 computer", "Introduction to distributed systems", "Inter­ process communication" and "SHIFT, heterogeneous workstation services at CERN". Triggering and data acquisition for future colliders was covered in: "Neu­ ral networks for trigger" and "Architecture for future data acquisition sys­ tems". Analysis of experiments was treated in two series of lectures: "Off-line software in HEP: experience and trends", and "Is there a future for event display?". Design techniques were the subject of lectures on: "Computer-aided de­ sign of electronics", "CADD, computer-aided detector design" and "Software design, the methods and the tools". The other lectures reproduced here treated various fields: "Second gen­ eration expert systems", "Multidatabase in health care systems", "Multimedia networks, what is new ?", "Pandora: an experimental distributed multimedia, system", "Benchmarking computers for HEP", "Experience with some early computers" and "Turing and ACE; lessons from a 1946 computer design". Ml Preface The fifteenth CERN School of Computing took place in L'Aquila, Italy. Sixty-six students from fourteen countries participated. The School was organised in collaboration with the "ïstituto Nazionale di Fisica Nucleare" (INFN). We are very grateful to Drs. Sandro Centro and Enzo Valente for their participation in organising the School, and we thank Professor N. Cabibbo for his active support. The School was hosted by the "Scuola Superiore Guglielmo Reiss Romoli". We were impressed by the excellent facilities offered by this centre and we wish to express our sincere thanks to its Director, Professor S. Rotella, and to his representative Dr. B. Santariga for making it possible to use their facilities. The assistance provided by the staff of the "Sculoa Superiore G. Reiss Romoli" is gratefully acknowledged. Special thanks go to the print shop, who produced thousands of pages at very short notice and to the people who assisted with the e-mail facility and the PCs. Mrs. Ingiacomo and Messrs de Meo and Aglioti were also of great help. The lecture programme was again varied and greatly appreciated by the partici­ pants. All lecturers are sincerely thanked for their efforts in preparing and delivering their lectures, for providing written accounts of their presentations, and for their availability to discuss with the students. The lecture programme was complemented by excellent introductions to software design methods and tools, followed by very demanding practical work. Most of the students tackled the practical excercises with great interest and enthusiasm. Drs. Paolo Palazzi and Stephen Fisher, who organised the practical sessions are very warmly thanked for their efforts and congratulated with the results. Our sincere thanks also go to their assistants: Arash Khodabandeh, Alberto Aimar, Tlior Lunde and Bernard Sarosi. An excursion was organised to the near-by Gran Sasso Laboratory. The visit of the underground experimental halls was very much appreciated. We thank INFN and in particular Professor Navarro for organising this visit. The participants will certainly remember the excellent meals served by the restau­ rant of the Reiss Romoli centre. The manager, Mr. Bardelli, and all his staff are sincerely thanked for having taken such good care of us. We express our gratitude to our secretaries, Mrs. Ingrid Barnett and Mrs Cristina Miletti. We thank the students for their active participation and we wish all of them success in their professional life. C.Verkerk Editor V ADVISORY COMMITTEE R. BRUN, CERN, Geneva, Switzerland B.E. CARPENTER, CERN, Geneva, Switzerland R.F. CHURCHHOUSE, University of Wales, Cardiff, U.K. (Chairman) R.W. DOBINSON, CERN, Geneva, Switzerland J J. THRESHER, CERN, Geneva, Switzerland C. VERKERK, CERN, Geneva, Switzerland ( Scientific Secretary) D.O. WILLIAMS, CERN, Geneva, Switzerland P. 2ANELLA, Geneva University, Switzerland and CRS4, Cagliari, Italy I. BARNETT, CERN, Geneva, Switzerland (School Secretary) Editor's Note No written account of the lectures by L. Mapelli, "Architecture of future data acquisition systems" was available, but numerous self-explanatory transparencies exist. The editor decided to exceptionally reproduce these transparencies as an Appendix to these Proceedings. These, combined with the paper by the same author in the Proceedings of the 1991 CERN School of Computing (Report CERN 92-02), should give a complete account of Mapeili's presentation in L'Aquila. vt Contents Abstract iii Preface v Advisory Committee vi Editor's Note vi Contents vii Software Design, the methods and the tools S.M. Fisher and P, Palazzi 1 Status of Parallel Computing P. Zanella 7 An Introduction to the APE100 Computer N. Cabibboy F. Rapuano and R. Tripiccione 21 Introduction to Distributed Systems S.J. Mullender 29 Interprocess Communication S.J. Mullender 47 SHIFT, Heterogeneous Workstation Services at CERN G. Lee and L. Robertson 80 Off-line Software in HEP: Experience and Trends N.A. McCubbin 90 Is there a Future for Event Display? H. Drevermann, D. Kuhn and B.S. Nilsson 102 Neural Networks for Trigger S.R. Amendolia 135 Computer-aided Design for Electronics S. Centro 160 CADD, Computer Aided Detector Design P.M. Ferran 167 Second Generation Expert Systems D.A. Bell 177 VII Benchmarking Computers for HEP E. Mcintosh 186 Multidatabases in Health Care systems D.A. Bell 204 Multimedia Networks; what's new? DM. McAuley 215 Pandora: An experimental distributed multimedia system D.R. McAuley 220 Experience with Some Early Computers R.F. Churchhouse 223 Turing and ACE; Lessons from a 1946 Computer Design B.E. Carpenter 230 Appendix Architecture of future data acquisition systems L. Mapelli 237 List of Participants 336 vili Software Design, the methods and the tools S.M. Fisher, RAL. Chilton. UK P. Palazzi, CERN, Geneva. CH Abstract OMT, a, method for software design, was introduced and compared with similar approaches and related CASE tools were demonstrated. Students formed teams and each team chose a project and applied OMT as far as producing a design document. The course was based on a book by J. Rumbaugh et al. so we just explain the outline of the course and refer our readers to the book. 1 Summary of lectures A software system goes through phases of requirements analysis, design, implementation, testing, operations and maintenance. After analysis (what to build), comes the design phase (how to build it): system design requires decisions about architecture then detailed design concentrates on mapping of data structures and on algorithms. Design makes use of models, abstractions of a system that permit us to understand it before we build it. To build a complex system, the developers use different views of the system, build models using a, precise notation, verify that the models satisfy the requirements of the system, and gradually add detail to transform the models into an implementation. A methodology is a combination of models with a prescription to use them across the software lifecycle. The Object Modelling Technique (OMT) is a methodology that spans analysis, design and implementation using a single terminology, and can have various targets, including conventional programming languages as well as 00 ones. OMT is based on extensions to three well proven models: object : describes the structure of the data with an an extended ER model. dynamic : models temporal relationships of those objects having significant dynamic behaviour using interacting finite state machines. functional : shows functional relationship among data values using a small extension to the Dataflow diagram of SA/SD. In the lectures OMT was compared with other object-oriented approaches as well as with SA/SD, Petri Nets and Entity-Relationship (ER) modelling.