TABLE OF CONTENTS The product selected by or provided to an owner or organization must meet its intended use or purpose. As has been discussed in previous chapters, the product must have the performance and sup-portability characteristics necessary for it to achieve a predetermined need. From the viewpoint of the owner, the goodness of the product is measured ultimately in being able to use the product when the need arises. It must be available for use when needed. Before starting a detailed investigation of these issues, a definition is necessary.
Availability The probability that an item is in an operable and committable state when called for at an unknown (random) time.
Having a system for the sheer act of possessing it gives no value to the owner. Value in possessing a system comes through the ability to actually use the system. Therefore, the ability to use a system becomes the final gauge of its value to the owner. The most common term for this value of a system is availability, or the ability to use the system when it is required. This concept can be compared to owning an automobile. Just having an automobile does not give sufficient value to the owner unless the automobile provides some form of transportation on demand. For example, if a person owns an automobile, but the automobile is inoperative owing to some failure, then the owner cannot use the automobile. Also, if there is no fuel or materials to make a...
