The inner workings of STEP are interesting enough to include an outline in this document. Because it does not fit well in the flow of the main text, this information is included in this appendix.
The STEP technology consists of five parts:
These protocols describe specific application fields. Not only do they describe which data is to be used to describe a product, but also how the data is to be used.
These are the common resources that are used by the application protocols. Everything is divided into separate resources, so that re-use is possible. A number of resources is earmarked especially for it's generic character in order to encourage their use, so that the costs of developing a new standard (using STEP) can be kept down.
This part describes how to map the models which have been formally specified in STEP into a format used in the specific STEP implementation. Also this part contains information on how to perform conformance testing.
In co-operation with above conformance specification (from the implementation & conformance part), this part provides the test data and criteria used to assess the conformance of a software package to the certain application protocol.
This is the bottom layer of STEP, explaining how to describe all STEP related models and software. An important part is the EXPRESS language reference, defining the data modelling language used in STEP.
Conformance means whether or not the data in question is conforming to the standard. This standard has to be known and formally specified in order to enable a check for standard conformance.