Introduction

Abstract

In the past decades, computer systems such as banking cash machine networks, networked business systems, or Internet services have become pervasive and gained significant importance in our daily private and business life. The flip side of the coin is computer systems not only having caused economic damage but also failures that lead to loss of life [Neumann, 1994]. Thus, a key concern is the trustworthiness of such systems with respect to safety, security, privacy, performance, correctness, and availability. In particular availability and correctness as the probability that a system is operable at a given time and provides the intended service is of utmost importance.