Introduction

This unit will deal with the following issues:

	Reliability can be applied whenever someone expects something or someone else to "behave" in a certain way.
	It is one of the metrics used to measure the quality of a software system.

	It is the most important quality factor sought in a product. Reliability is a user-oriented quality factor relating to
	system operation, and it takes into account the frequency of system failure.

	Intuitively, if the users of a system rarely experience system failure, then the system is considered to be more
	reliable than one that fails more often.

	Failure means the program in its functionality has no met user requirements in some way. Software reliability
	concerns itself with how well the software functions to meet the requirements of the customer.

	Software reliability is not a direct function of time. Hardware parts may become old and wear out with time, but
	software will not change over time unless the software is changed or modified intentionally.