Objective The aim of DELTA-4 is to formulate, develop and demonstrate an open, fault-tolerant distributed system architecture. The proposed project has direct applicability to wide application areas which include computer-integrated manufacturing, office systems, integrated information, processing systems and process control systems.The Delta-4 architecture features original fault concepts for the development and design of dependable open distributed computing systems. To tackle the complex dependability validation task, a comprehensive strategy incorporating both objectives of the validation process (fault removal and fault forecasting) has been followed that is based on the use of complementary validation methods. The methods considered include formal verification of the design of twospecific reliable communication protocols, experimental validation of the implementation of the fault tolerance mechanisms by means of physical fault injection and analytical modeling and evaluation of hardware and software. The paper summarixes the main characteristics (objectives, implementation and results) for each of the methods applied in this validation strategy.The aim of open systems interconnection was to formulate, develop and demonstrate an open, fault tolerant distributed system architecture.As an open system, Delta-4 has 3 important properties:implementations based on off the shelf heterogeneous computer systems are possible (the fault tolerant properties of the architecture are in no way dependent on the use of proprietary, fail safe or self checking processors);the architecture conforms to the open system interconnection (OSI) model and implementation are able to coexist with and interwork with systems communicating by the use of current standard International Standardization Organization (ISO) OSI protocols;the dependability and distribution properties of the architecture are offered in a transparent way to the user (both incremental dependability and incremental performance are offered on a service by service basis).The proposal has both a generic component and an implementation component. The generic component contributes to basic concepts in the areas of dependability, multipoint communications, system administration and open distributed processing. The implementation component serves to demonstrate the validity of the concepts; the use of an experimental site and pilot sites is intended to enable their correctness to be established.An open workshop presented a number of demonstrations, including the remote banking facility implemented in the DELTA-4 technology. The workshop also demonstrated, at system level, the effectiveness of the cloning of data and processes in achieving a dependable system. Results have been obtained in the area of system security based on fragmentation and scattering supported by DELTA-4 distributed technology.More work is required on the real time and performance aspects of this advance in distributed systems.As an open system, DELTA-4 has three important properties: - Implementations based on "off-the-shelf" heterogeneous computer systems are possible; the fault-tolerant properties of the architecture are in no way dependent on the use of proprietary, fail-safe or self-checking processors. - The architecture conforms to the OSI model and implementations are able to coexist with and interwork with systems communicating by the use of current standard ISO/OSI protocols. - The dependability and distribution properties of the architecture are offered in a transparent way to the user. Both incremental dependability and incremental performance are offered on a service-by-service basis. The proposal has both a generic component and an implementation component. The generic component is already contributing to basic concepts in the areas of dependability, multi-point communications, system administration and open distributed processing; these concepts are of value to other ESPRIT projects and to the standards community. The implementation component serves to demonstrate the validity of the concepts; the use of an experimental site and pilot sites is intended to enable their correctness to be established. Fields of science natural sciencescomputer and information sciencessoftwareengineering and technologyelectrical engineering, electronic engineering, information engineeringelectronic engineeringcontrol systems Programme(s) FP2-ESPRIT 2 - European strategic programme (EEC) for research and development in information technologies (ESPRIT), 1987-1992 Topic(s) Data not available Call for proposal Data not available Funding Scheme Data not available Coordinator Ferranti International plc EU contribution No data Address Simonsway Wythenshawe M22 5LA Manchester United Kingdom See on map Total cost No data Participants (12) Sort alphabetically Sort by EU Contribution Expand all Collapse all BULL SA France EU contribution No data Address Tour Bull 1 place Carpeaux 92800 PUTEAUX See on map Total cost No data Centre National de la Recherche Scientifique (CNRS) France EU contribution No data Address 7 avenue de Colonel Roche 31077 Toulouse See on map Total cost No data Fraunhofer-Gesellschaft zur Förderung der Angewandten Forschung eV (FhG) Germany EU contribution No data Address Sebastian-Kneipp-Straße 12-14 76131 Karlsruhe See on map Total cost No data INSTITUTO DE ENGENHARIA DE SISTEMAS E COMPUTADORES Portugal EU contribution No data Address APARTADO 10105, RUA ALVES REDOL, 9 1017 LISBOA See on map Total cost No data MARI Applied Technologies Ltd United Kingdom EU contribution No data Address Boldon Business Park Witney Way NE35 9PE Boldon See on map Total cost No data NATIONAL RESEARCH COUNCIL OF ITALY Italy EU contribution No data Address Via G. Moruzzi 1 56124 PISA See on map Total cost No data Renault Automation France EU contribution No data Address 8-10 avenue Émile Zola 92109 Boulogne-Billancourt See on map Total cost No data Sema Group SA France EU contribution No data Address 16-20 rue Barbes 92126 Montrouge See on map Total cost No data UNIBANQUE-CREDIT AGRICOLE France EU contribution No data Address 40 RUE D'ORADOUR SUR GLANE 75015 PARIS See on map Total cost No data UNIVERSITY OF NEWCASTLE UPON TYNE United Kingdom EU contribution No data Address NE1 7RU Newcastle upon Tyne See on map Total cost No data United Kingdom Atomic Energy Authority (UKAEA) United Kingdom EU contribution No data Address 11 Charles II Street SW1Y 4QP London See on map Total cost No data Université de Grenoble I (Université Joseph Fourier) France EU contribution No data Address 385 avenue de la Bibliothèque 38041 Grenoble See on map Total cost No data