Engineering fault tolerance

以计算机为基础和控制的系统的范围和复杂性继续急剧增加。现代软件必须满足越来越多的需求，提供实时功能，并且必须在异构和不断变化的环境中与其他软件系统进行交互。越来越多的提供关键功能的责任由软件承担，因此这种系统以不可预测的方式行为的后果可能是相当可观的。为了成功地构建这种可靠的“系统的系统”，应用程序必须被设计成即使有故障也能提供服务的方式。它们必须能够容忍环境中外部实体的意外行为、不可靠的底层组件、通信故障、错误的数据和错误的算法。

The scope and complexity of computer-based and controlled systems continue to increase dramatically. Modern software must satisfy an increasing number of requirements, provide real-time functionality, and has to interact with other software systems in a heterogeneous and changing environment. More and more responsibility of providing critical functionality is assumed by software, and hence the consequences of such systems behaving in an unpredictable way can be considerable. To successfully build such dependable "systems of systems", applications have to be engineered in such a way that they can provide service in spite of faults. They must be able to tolerate unexpected behavior of external entities in their environment, unreliable underlying components, communication failures, erroneous data and faulty algorithms.