(ref.doc)IEEE Spectrum

IEEE Spectrum

August 1992

pp 56-60
Measuring software reliability
by Shari Lawrence Pfleerger

An *error* is a human mistake

The resulting *fault* is an accidental condition that causes a unit of
the system to fail to function as required. Thus, the fault is a
manifestation of an error in the software. Sometimes, faults are
called bugs.

Faults often lead to a *defect* -an anomaly in a product.

A *failure* occurs when a functional unit [...]can no longer perform
its required action.


The standard IEEE/ANSI definition [982.2] requires the system to be
completely designed, developed, and operational before reliability can
be measured.