Software now controls banking systems, all forms of telecommunications, process control in nuclear plants and factories, as well as defense systems. Even in households without a PC, many of the gadgets and the automobiles are software controlled. The society has developed an extraordinary dependence on software. There are many well known cases of tragic consequences of software failures. In pop...

Unreliability of any product comes due to the failures or presence of faults in the system. As software does not “wear-out” or “age”, as a mechanical or an electronic system does, the unreliability of software is primarily due to bugs or design faults in the software. Reliability is a probabilistic measure that assumes that the occurrence of failure of software is a random phenomenon. Randomnes...