Dependable Computing

Abstract

The dependability of systems is known as the reliance that can justifiably be placed on the service the system delivers. Dependability has become an important aspect of computer systems since everyday life increasingly depends on them, which has left us vulnerable to their potential malfunction. The causes to these malfunctions can potentially be introduced in every step of their development, deployment and operation. Hence the basic concerns associated with dependable systems: how to build them? What design principles are involved? How should these systems be evaluated?The basic concepts and taxonomy associated with dependability were recently presented in a paper by Avizienis, Laprie, Randell and Landwehr on the first issue of the IEEE Transactions of Dependable and Secure Computing. It is clear from this key publication that dependability is in fact an integrating concept that encompasses several main attributes: availability, reliability, safety, integrity, and maintainability. When addressing security, confidentiality is an additional attribute, which allows to define security as a composite attribute of confidentiality, integrity and availability. There are several means for attaining these attributes, which can be grouped into four major categories. Rigorous design, which aims at preventing the occurrence or the introduction of faults. Verification and validation, which aims at reducing the number or severity of faults. Fault tolerance, which aims at delivering correct service despite the presence of faults. System evaluation, which aims at estimating the present number, the future incidence, and the likely consequences of faults. Dependability can be attained by the combined use of rigorous design, verification and validation, and fault tolerance, while system evaluation should demonstrate that dependability was indeed attained.For this special issue, we have received 24 submissions dealing with a wide range of issues related to dependability. The papers sent for reviewing were carefully evaluated by at least 4 referees. This thorough reviewing process has led to the acceptance of 5 high-quality papers. Below, we provide a brief overview of these papers, which fall mainly in the areas of fault tolerance and system evaluation.In the paper "A Systematic Approach for Structuring Exception Handling in Robust Component-Based Software", F. Castor Filho, P. A. de C.