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A: In order to answer this question, we should first distinguish between the terms compliance and conformance as they relate to industry standards, since these terms are frequently conflated.
Standards compliance is an informal industry term which indicates that a system or product provides at least partial support to a particular industry standard, but this partial support is typically not subjected to formal testing. In contrast, conformance is a more formal industry term which indicates that a system or product provides full support for a particular industry standard, where the conformance can be verified by formal testing. From these definitions it should be clear that compliance, which is loosely defined, is much easier for a vendor to claim than conformance, which should be subject to formal testing by a neutral third party, such as an international standards organization.
Re OMG SysML compliance: The OMG SysML specification (see OMG SysML v. 1.2, Chapter 5) defines three compliance levels that reference both UML2 metamodel baseline (UML4SysML) Packages and the SysML (Profile) Extension Packages that customize UML2 syntax and semantics for the SysML dialect. In addition, compliance for any given level can be further refined by three sub-classifications: compliance by abstract syntax (metamodel compliance), compliance by concrete syntax (notational compliance), and abstract syntax with concrete syntax compliance. Although vendors of OMG SysML compliant systems or products appear to be expected to offer documentation that describes specific OMG SysML compliance levels, this does not yet appear to be a common practice.
Until recently, the OMG did not provide a standard test suite to formally and objectively test OMG SysML compliance; it was left up to SysML tool vendors to informally and subjectively provide their own documentation to describe their product compliance level. It should nor be surprising then, that many SysML tool vendors claim some sort of "OMG SysML support" but SysML language implementations are frequently inconsistent, and model interoperability is generally dysfunctional. However, in December 2011 six tool vendors participating in the OMG Model Interchange Working Group (MIWG) announced the public availability of a test suite and test case results that demonstrate UML and OMG SysML model interchange capability using the XML Metadata Interchange (XMI) standard. Information on the test suite is available at the MIWG Wiki.
Given the past track records of SysML and UML tool vendors, it is too early to assume that SysML and UML tool interoperability problems have been completely resolved. However, SysML users are encouraged to perform their own due diligence regarding SysML tool interoperability by performing their own pragmatic tests. (For example, draw or borrow a medium-size OMG SysML model with a tool claiming OMG SysML compliance, export it using the OMG XMI interchange format, and attempt to import the exported XMI file into another competitive SysML that claims comparable OMG SysML compliance. If you can successfully import into the competitive tool without significant loss of information.) You can inform the OMG about any concerns that you have regarding OMG SysML compliance, conformance, or any other technical issue by sending email to issues@omg.org.
Q: What is the difference between SysML compliance and conformance?
A: In order to answer this question, we should first distinguish between the terms compliance and conformance as they relate to industry standards, since these terms are frequently conflated.
Standards compliance is an informal industry term which indicates that a system or product provides at least partial support to a particular industry standard, but this partial support is typically not subjected to formal testing. In contrast, conformance is a more formal industry term which indicates that a system or product provides full support for a particular industry standard, where the conformance can be verified by formal testing. From these definitions it should be clear that compliance, which is loosely defined, is much easier for a vendor to claim than conformance, which should be subject to formal testing by a neutral third party, such as an international standards organization.
Re OMG SysML compliance: The OMG SysML specification (see OMG SysML v. 1.2, Chapter 5) defines three compliance levels that reference both UML2 metamodel baseline (UML4SysML) Packages and the SysML (Profile) Extension Packages that customize UML2 syntax and semantics for the SysML dialect. In addition, compliance for any given level can be further refined by three sub-classifications: compliance by abstract syntax (metamodel compliance), compliance by concrete syntax (notational compliance), and abstract syntax with concrete syntax compliance. Although vendors of OMG SysML compliant systems or products appear to be expected to offer documentation that describes specific OMG SysML compliance levels, this does not yet appear to be a common practice.
Until recently, the OMG did not provide a standard test suite to formally and objectively test OMG SysML compliance; it was left up to SysML tool vendors to informally and subjectively provide their own documentation to describe their product compliance level. It should nor be surprising then, that many SysML tool vendors claim some sort of "OMG SysML support" but SysML language implementations are frequently inconsistent, and model interoperability is generally dysfunctional. However, in December 2011 six tool vendors participating in the OMG Model Interchange Working Group (MIWG) announced the public availability of a test suite and test case results that demonstrate UML and OMG SysML model interchange capability using the XML Metadata Interchange (XMI) standard. Information on the test suite is available at the MIWG Wiki.
Given the past track records of SysML and UML tool vendors, it is too early to assume that SysML and UML tool interoperability problems have been completely resolved. However, SysML users are encouraged to perform their own due diligence regarding SysML tool interoperability by performing their own pragmatic tests. (For example, draw or borrow a medium-size OMG SysML model with a tool claiming OMG SysML compliance, export it using the OMG XMI interchange format, and attempt to import the exported XMI file into another competitive SysML that claims comparable OMG SysML compliance. If you can successfully import into the competitive tool without significant loss of information.) You can inform the OMG about any concerns that you have regarding OMG SysML compliance, conformance, or any other technical issue by sending email to issues@omg.org.
Keep in mind that you can request additional questions to be answered in the SysML FAQ by sending email to FAQ@SysMLforum.com.
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