Jackson system development

Jackson system development is a method that has at its basis the assertion that any computer system is in reality a model of some portion of the real world. The Jackson system development method is a technical method that is limited to the software life cycle. The method addresses all stages of the life cycle. As originally developed the method acted as a framework for other specialist techniques at various stages. The method is suitable from that stage in a project where only an outline of requirements exists, through to the maintenance phase of the finished product. Jackson system development belongs to a small family of development methods characterised as operational. The operational paradigm differs from the conventional waterfall model of system development. Instead there are three main phases involved which are summarised: modelling phase: as part of the analysis process, aspects of the real world relevant to the system being developed are modelled; specification phase: the modelling of the previous step provides the basis of a system specification to which is added the necessary structures to realise the required functionality; implementation phase: an operational specification is executable in the sense that it expresses desired system behaviour in terms of some abstract machine.<>