View MODAF:System


Version & Date

Version 1.2.004.

See MODAF Release History.


Part of the MODAF System Viewpoint. From the MODAF Metamodel (M3):

The usage of an artefact as a System in a PhysicalArchitecture.

Subject to Crown Copyright

Tests For

Tests Against



System participates in:

Configuration History

1.2.004 definition changed
1.2.002 definition:

The usage of an artefact as a System in a Capability Configuration.

Subject to Crown Copyright
1.1 definition:

A coherent combination of physical artefacts, energy and information, assembled for a purpose.

Subject to Crown Copyright


Still a poor definition as it doesn’t define what a system is. A ‘system’ is a system because of unique properties such as emergent behaviour not because of its use - a system is not a use of anything.

A consistency problem arises in MODAF because the metamodel has overlapping concepts e.g. Platform, System so that one person’s system is another’s platform and they therefore choose different stereotypes to represent the same real world thing. The usage is an attempt to knit together the results of different choices by architects offered by the MODAF metamodel.

System in MODAF is defined as part of the physical architecture (a ‘hard system’):


It is defined as an Artefact alongside Platform. This arose because when the MODAF was originally launched the consensus on what a system is wasn’t the currently accepted one with emergence et al and the MODAF quite reasonably took the then accepted view - hence it is a purely man-made thing. No notion of complexity whatsoever.

  From the The MODAF System Viewpoint(SV) (17th February 2009):
‘Artefacts - Physical objects made for a purpose (e.g. system, sub-system, platform, component or any physical item that occupies space and has attributes)’

‘Physical Architectures - Configurations of resources for a purpose (e.g. capability configurations)’

‘The physical resources contributing to a capability must either be an organisational resource or a physical asset. That is, a system cannot contribute alone; it must be hosted on a physical asset used by an organisational resource of both. Organisational aspects (e.g. who uses a system) can now be shown on SV-1.’

Subject to Crown Copyright

In short as it is defined in MODAF 1.2:

  • system is something physical
  • it is man-made
  • it can’t contain anything else like Organisation, Post or Role, or Software
  • it is not the same thing as a Capability Configuration
  • systems cannot provide capability


MODAF::System is very similar to the NAF::System.

It is in keeping with the then thinking in the field. In ‘Systems Engineering - Coping with Complexity’ (1998) section 1.2, p6:

Frequently throughout the text, the word systems is used synonymously with a product. ... a product is an artefact ( a human-made entity with a distinguishing and identifiable purpose)

This is a very human-centric view of the world and means that most natural are not systems on this basis. The Mk1 Human Being is clearly not a system according to this definition!

The TRAK::System isn’t a product and can include people.

Other Frameworks



  • MODAF Metamodel (M3). v1.2.004.
  • Systems Engineering: Coping with Complexity by Stuart Arnold, Peter Brook, Ken Jackson, Richard Stevens published in 1998



Category:Metamodel -> Stereotype
Category:MODAF -> Viewpoint -> Systems



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