Software reliability is described with respect to
(A) Execution Time
(B) Calendar Time
(C) Clock Time
Choose the correct answer from the options given below:

Explanation

In Musa's software reliability engineering, reliability is always quoted against a time base, and three time bases are defined. Execution time is the CPU time actually spent executing the program and is the base preferred for reliability modelling. Clock time is the elapsed wall-clock time from start to end of execution, including waiting time but excluding periods when the computer is shut down. Calendar time is ordinary chronological time and is what customers and managers usually talk in. Since all three are standard bases for expressing software reliability, option 3, "(A), (B) and (C)", is correct.