The reliability of software is becoming increasingly important to a large range of industries that rely on complex computer systems and machinery with computer control. The reliability of a system depends on both the hardware and the software that comprise the system. Although faults in design can continue to give problems, the issues and the techniques for meeting severe reliability requirements in hardware have been understood for some time. In the case of software both the techniques and a positive attitude of software developers to the achievement of reliability are much less well established. They are particularly crucial in the development of software dependent safety-critical systems.There are genuine differences between software and hardware: software has no physical existence; software includes data as well as logic; few software quality metrics exist; it is deceptively easy to introduce changes into software; effects of software changes propagate explosively; software developments have traditionally made very little use of pre-existing components; software may have much higher complexity than hardware (to the extent of attempting to implement functionality of a complicity that would be unacceptable for hardware). However, in many ways software development is like hardware development and can be managed and controlled using very similar techniques to those used in any other engineering discipline. The differences listed above are the very factors which make a genuine engineering approach essential for the successful development of reliable software. Improvements in the technology of software development have reached the point where the major issues have been identified and considerable progress has been made in addressing them.Methods for technical software development are well defined and practical working tools to support improved software production are commonly available. Experience shows that application of the right methods can bring significant improvements in quality and productivity, and this handbook brings together the various aspects of software development into an integrated coverage of the subject of developing reliable software. This handbook represents a unique reference work which provides: complete and comprehensive subject matter - based on real experience rather than hypothesis; straightforward reading - a reference point for technical staff, managers and customers; extensive references - for experts who require more in-depth subject coverage; appendices - containing technical material supporting the subject of software reliability. The Software Reliability Handbook provides an essential contribution to the successful production of reliable software systems.Sponsored by the Alvey Directorate, this book will be an essential tool for those involved with the increasing reliance placed on computer software in control systems of aircraft, power stations and vehicles, especially where life is at risk.
