Look to this innovative resource for the most-comprehensive coverage of software fault tolerance techniques available in a single volume. It offers you a thorough understanding of the operation of critical software fault tolerance techniques and guides you through their design, operation and performance. You get an in-depth discussion on the advantages and disadvantages of specific techniques, so you can decide which ones are best suited for your work.

Look to this innovative resource for the most comprehensive coverage of software fault tolerance techniques available in a single volume. It offers you a thorough understanding of the operation of critical software fault tolerance techniques and guides you through their design, operation and performance. You get an in-depth discussion on the advantages and disadvantages of specific techniques, so you can decide which ones are best suited for your work. The book examines key programming techniques such as assertions, checkpointing, and atomic actions, and provides design tips and models to assist in the development of critical fault tolerant software that helps ensure dependable performance. From software reliability, recovery, and redundancy... to design and data diverse software fault tolerance techniques, this practical reference provides detailed insight into techniques that can improve the overall dependability of your software.

This book presents the theory behind software-implemented hardware fault tolerance, as well as the practical aspects needed to put it to work on real examples. By evaluating accurately the advantages and disadvantages of the already available approaches, the book provides a guide to developers willing to adopt software-implemented hardware fault tolerance in their applications. Moreover, the book identifies open issues for researchers willing to improve the already available techniques.

Software fault tolerance techniques involve error detection, exception handling, monitoring mechanisms, and error recovery. This issue of Trends in Software focuses on identification, formulation, application, and evaluation of current software fault tolerance techniques.

The production of a new version of any book is a daunting task, as many authors will recognise. In the field of computer science, the task is made even more daunting by the speed with which the subject and its supporting technology move forward. Since the publication of the first edition of this book in 1981 much research has been conducted, and many papers have been written, on the subject of fault tolerance. Our aim then was to present for the first time the principles of fault tolerance together with current practice to illustrate those principles. We believe that the principles have (so far) stood the test of time and are as appropriate today as they were in 1981. Much work on the practical applications of fault tolerance has been undertaken, and techniques have been developed for ever more complex situations, such as those required for distributed systems. Nevertheless, the basic principles remain the same.

The first ESPRIT programme contained several ambitious projects. of which REQUEST. with its wide brief covering all issues of assessment of quality and reliability of software process and product. was one. Within REQUEST. the research described in this volume. concerning those special problems of software that is required to have extremely high reliability. was particularly difficult and ambitious. The problems of software reliability are essentially twofold. On the one hand there is a concern with methods for achieving adequate reliability. on the other hand there is a need to evaluate what has actually been achieved in a particular case. Naturally. far more effort has been spent over the years on the former problem; indeed. there is a sense in which all of conventional software engineering can be seen as a response to this problem. However. it is becoming clearer than ever that we can only claim to have a truly sCientific approach. and so justify the description software engineering. when we are able to measure the attributes of process and product. It is still common to find software development methods recommended to users on purely anecdotal grounds. This is not good enough. Rational choices between rival approaches can only be made on the basis of quantified costs and benefits. Even more worrying is the tendency to argue that a software product can be depended upon merely because it has been developed by honest men using such anecdotal 'good practice'.