Dependability evaluation main objective is to assess the ability of a system to correctly function over time. There are many possible approaches to the evaluation of dependability: in these notes we are mainly concerned with dependability evaluation based on probabilistic models. Starting from simple probabilistic models with very efficient solution methods we shall then come to the main topic ...

This paper gives the main definitions relating to dependability, a generic concept including as special case such attributes as reliability, availability, safety, confidentiality, integrity, maintainability, etc. Basic definitions are given first. They are then commented upon, and supplemented by additional definitions, which address the threats to dependability (faults, errors, failures), and ...

Many large software systems have diierent components with varying requirements for robustness and performance. Moreover, dependability requirements often change throughout their software life-cycle. Thus any single dependability technique is insuf-cient for implementing large systems. Software developers need to be able to modify dependability code without modifying application code. We outline...

The assessment of the dependability properties of a system (dependability benchmarking) is a critical step when choosing among similar components/products. This paper presents a proposal for the benchmarking of the dependability properties of web-servers. Our benchmark is composed of the three key components: measures, workload, and faultload. We use the SPECWeb99 benchmark as starting point, a...

Building dependable distributed systems from commercial off-the-shelf components is of growing practical importance. For both cost and production reasons, there is interest in approaches and architectures that facilitate building such systems. The AQuA architecture is one such approach; its goal is to provide adaptive fault tolerance to CORBA applications by replicating objects, providing a hig...

Serious accidents in the last years, e.g. Concorde disaster, long-distance train ICE 3rd generation, and countless and increasing rates of call-back actions of automobiles because of failures, underline the necessity for systematic dependability analysis and integrative dependability design. The different technological areas (mechanics, electronics, information and communication technology) and...

This paper introduces a dependability assessment tool (WSsDAT) for Web Services monitoring and testing. It allows users to evaluate dependability of Web Services from the point of view of their clients by collecting metadata representing a number of dependability metrics. This Java-based tool can be deployed in diverse geographical locations to monitor and test the behaviour of a selected set o...

As Web service-based system integration recently became the mainstream approach to create composite services, the dependability of such systems becomes more and more crucial. Therefore, extensions of the common service composition techniques are urgently needed in order to cover dependability aspects and a core concept for the dependability estimation of the target composite service. Since Web ...

We present the specification of a basic library of dependability mechanisms that can be used within automated approaches for synthesising dependable Connectors in heterogeneous networks. The library builds on classical dependability patterns, such as majority voting and retry, and uses the concept of overlay networks for triggering the synthesis of specific dependability mechanisms in the Conne...

This paper describes a model that defines the attributes of domestic systems that lead to system dependability and a user-oriented specification method for support systems based on this model. We start by discussing technical dependability models and discuss how these have to be extended for use in a domestic context. We present an extended dependability model based on a socio-technical perspec...