DeviceDefinition allows specification of a device's components via the hasPart element which referenced component DeviceDefinitions. Each part has a count associated with it ("there are 4 leads of this definition on this device"), however it is unclear whether the parts listed are an exact set of parts, a minimal set, a maximal set, or optional parts.

If the parts listed are an exact set, then every variation in device component configuration (in terms of what is present) would require a separate Definition. It would also suggest that for a Device operating with 1 of X component rather than the 2 of X component it is capable of supporting, but isn't currently equipped with, should have a different Definition.

Other ways of interpreting "hasPart" would be:

• "these are the parts that every device using this Definition will have, although there may be other parts not listed" (minimal parts definition)
• "this is the full list of potential parts that devices using this Definition may have, although individual instances may not have all of these" (maximal parts definition).

In any case where the list of parts does not match the exact configuration of the Device, we also have to consider whether alternative parts are listed ("the device must have one of these OR one of those", "the device can have one of these OR one of those").