Essential systems analysis was a new methodology for software specification published in 1984 byStephen M. McMenamin andJohn F. Palmer for performingstructured systems analysis based on the concept ofevent partitioning.[1]
Theessence of a system is "its required behavior independent of the technology used to implement the system".[2] It is an abstract model of what the system must do without describing how it will do it.[2]
Themethodology[1] proposed that finding the true requirements for aninformation system entails the development of an essential model for the system, based on the concepts of a perfect internal technology, composed of:
Edward Yourdon later adapted it to developmodern structured analysis.[3]
The main result was a new and more systematic way to develop thedata-flow diagrams, which are the most characteristic tool ofstructured analysis.
Essential analysis, as adopted inYourdon's modern structured analysis, was the main software development methodology untilobject-oriented analysis became mainstream.
