Military Handbook- Electronic Reliability Design Handbook (1998)

For all but the most recent years of human history, the performance expected from man’s implements was quite low and the life realized was long, both because it just happened to be so in terms of man’s lifetime and because he had no reason to expect otherwise. The great technological advances, beginning in the latter half of the twentieth century, have been inextricably tied to more and more complex implements or devices. In general, these have been synthesized from simpler devices having a satisfactory life. It is a well known fact that any device which requires all its parts to function will always be less stable than any of its parts. Although significant improvements have been made in increasing the lives of basic components - for example, microelectronics - these have not usually been accompanied by corresponding increases in the lives of equipment and systems. In some cases, equipment and system complexity has progressed at so rapid a pace as to negate, in part, the increased life expected from use of the longer-lived basic components. In other cases, the basic components have been misapplied or overstressed so that their potentially long lives were cut short. In still other cases, management has been reluctant to devote the time and attention necessary to ensure that the potentially long lives of the basic components were achieved.

The military services, because they tended to have the most complex systems and hence the most acute problems, provided the impetus to the orderly development of the discipline of reliability engineering. It was they who were instrumental in developing mathematical models for reliability, as well as design techniques to permit the quantitative specification, prediction and measurement of reliability.