SYSML11 — Section: 08 Blocks, Annex B, Annex C

It is not enough to refer simply to (p.180): 'The «system» and «external» stereotypes are user defined, not specified in SysML,' Although already raised as Issue 12257, this new Issue submission (by a different submitter) makes the constructive suggestion that the 'user defined' stereotypes by defined in non-normative extension Section in the Annex C. It is not acceptable that a specification dedicated to systems engineering does not even have at least a well-defined non-normative definition of a <<system>> and <<system context>> ! These need to be upgraded to a non-normative Annex, and then introduced properly through the example. I see no reason why the figures should not use non-normative stereotypes as long as they are defined in an Annex and clearly. This is not the case for <<system context>>, <<system>>, <<external>>, <<domain>>, <<subsystem>>, yet these are truly crucial for even basic systems engineering, and the examples (which use them well) make little sense without them. There is a very nice summary of C.2 Requirements Diagram Extensions. and those requirement categories have proved very useful already. I have made a small summary and guide here: http://school.nomagic.com/node/396 Block extensions (non-normative) As recommended through SysML1.0 examples: * «system» top-level block to be used in a system context * «subsystem» grouping (usually physical) within a system * «external» outside the top-level system (yet affecting it) * «domain» provides a common context for a system and externals * «system context» a particular context for a system and externals Note my definitions for <<domain>> vs. <<system context>>. I suggest that at least «system context» should have a tag: system:<<system>>[1] <<domain>> could then extend <<system context>>. Visit also: http://school.nomagic.com/node/415

As noted by the issue,Section B.4.2.1, Internal Block Diagram - Setting Context,
includes the following sentence:
The «system» and «external» stereotypes are user defined, not specified
in SysML, but help the modeler to identify the systemof interest relative to
its environment.
Many forms of non-normative stereotypes could be developed to distinguish
particular user modeling distinctions and practices. The issue itself notes possibly
different stereotypes (such as «domain») than those used in the example. The
availability of user-defined stereotypes to make such distinctions is clearly
indicated by the example.Rather than incorporating a particular set of
stereotypes directly in the SysML specification, the original submission
deliberately left these open-ended to support possibly different modeling needs.
Multiple sets of these stereotypes could be developed as part of separately
distributed model libraries. Since the SysML specification is primarily concerned
with the definition of the core SysML language, the omission of further detailed
specification of user-model stereotypes is in keeping with the scoping decisions
of the material to be maintained as a direct part of the SysML specification.
Disposition: Closed, no change