From Traditional Fault Tolerance to Blockchain

1Introduction

Distributed systems bring many benefits to us, for example, we can share resources such as data storage and processing cycles much more easily; we can collaborative on projects efficiently even if the team members span across the planet; we can solve challenging problems by utilizing the vast aggregated computing power of large scale distributed systems. However, if not designed properly, distributed systems may appear to be less dependable than standalone systems. As Leslie Lamport pointed out: “You know you have one (a distributed system) when the crash of a computer you’ve never heard of stops you from getting any work done” [10]. In this book, we introduce various dependability techniques that can be used to address the issue brought up by Lamport. In fact, with sufficient redundancy in the system, a distributed system can be made significantly more dependable than a standalone system because such a distributed system can continue providing services to its users even when a subset of its nodes have failed.

In this chapter, we introduce the basic concepts and terminologies of dependable distributed computing and system security, and outline the primary approaches to achieving dependability.

1.1 Basic Concepts and Terminologies for Dependable Computing

The term “dependable systems” has been used widely in many different contexts and often means different things. In the context of distributed computing, dependability refers to the ability of a distributed system ...