System Dependability

The paper starts with a brief account of how and why, at about the time of the birth of what is now INRIA, the author and his colleagues became interested in the subject now known as system dependability. The main body of the paper summarizes the work over the last three years of the ESPRIT Basic Research project on Predictably Dependable Computing Systems (PDCS). This is a long term collaborative research activity, centred on the problems (i) of producing quantitative methods for measuring and predicting the dependability of complex software/hardware systems, (ii) of incorporating such methods into the design process, and (iii) of developing appropriate architectures and components as bases for designing predictably dependable systems. A further section of the paper then describes, in somewhat more detail, one of the current activities within PDCS. This is work being carried out by the author in collaboration with an INRIA colleague, Dr. Jean-Charles Fabre, on a unified approach to providing both reliability and security termed ObjectOriented Fragmented Data Processing (OOFDP).