TABLE OF CONTENTS life is what happens to you whilst you're busy making other plans
John Lennon
Life cycles and life cycle models are very widely misunderstood concepts. Despite the fact that they are fundamental to almost every project, life cycles and life cycle models are often confused and the terms used (incorrectly) interchangeably. There is also a great deal of misunderstanding about how processes relate to both of these concepts and, once more, people often use the term 'process' interchangeably with both life cycle and life cycle model [7].
A life cycle describes the evolution of a system from conception to its ultimate demise. The most obvious analogy to this is a human life where the life cycle starts at the actual conception, rather than birth, and continues on until death.
A life cycle is smade up of a number of phases, each of which will implement one or more processes. It follows, therefore, that in order to define a life cycle, its phases must be defined. In order to define a phase, its associated process, or processes, must also be defined. Bearing in mind that a set of processes has been defined in Chapter 6, it is possible to define a life cycle using these processes.
A life cycle model describes the configuration of a life cycle for a particular project, or to put it another way, a life cycle model defines the order in which the processes are carried out and is defined...
