
Software Reliability ◾ 495
rst model to insist on using execution time to capture inter-failure times.
However, it also includes a model of calendar time, so that we can make
project management estimates, such as the time until target reliability is
achieved. By tying reliability to project management, Musa encouraged
the widespread use of reliability modeling in many environments, par-
ticularly telecommunications.
11.3.3 The Littlewood Model
e Littlewood model (denoted LM in subsequent gures) attempts to be a
more realistic nite fault model than JM by treating the hazard rates (cor-
responding to the dierent faults) as independent ra ...