IDEF (Ø-5) integrates the modelling of people, processes,
machines, materials, computers and information. IDEF describes
what a system does, who controls it, what it works on, how it
performs functions and what it produces. Diagrams are based
upon simple box and arrow graphics used to produce a ‘function
model’ – a structured representation of functions, activities
or processes within the modelled system. Diagrams adhere to
hierarchical decomposition, beginning with a high-level context
diagram, representing the whole system as a single unit (one
box with arrow interfaces linking to other processes outside the
system).