HP Matrix Operating Environment Software - Manual (Page 89)

Figure 5 Unmanaged storage array XML object model
Entity
All objects in this model derive from the Entity class, and therefore they all have an ObjectID. An
ObjectID is a string that contains a unique identifier. ObjectIDs must be unique across all XML files
to be loaded by SPM. If there is a conflict, the second file containing the conflicting ObjectID will
be ignored. ObjectIDs are optional except when an object must be referenced from another object
in an XML file. SPM will generate an ObjectID for any objects that do not have one specified in
the XML file.
XML object model 89