HP WBEM Services for HP-UX and Linux System Administrator's Guide

How Resources are Represented (CIM Schema)
Appendix A 93
Consider how to uniquely identify a user account on a Unix system. You
could use two key properties: the value of the user account’s Name
property and the value of the system’s Name property. Consider also the
identifying pair used to route your email to you:
user-name@domain-name.
Classes are either concrete or abstract. A concrete class (like
CIM_Operating System) has real instances, particular computer
systems. A concrete class must have at least one key property. An
abstract class like CIM_ManagedElement can not have any instances,
and it is not required to have key properties. Its subclasses can have keys
as they get more specific.
Associations can be defined between classes. For example, there is a
ParticipatingCS association between CIM_ComputerSystem (the entire
computer system) CIM_Operating System (the OS software that exists
on that system).
The association itself is a class, so it can have properties and methods.
For example, two properties of ParticipatingCS are RoleOfNode and
StateOfNode.
Namespaces can give you a logical way to group things, in order to
control their scope and visibility. A namespace is not a physical location;
it is more like a logical database containing specific classes and
instances. Namespace grouping can be used to separate instances and
make sure there are no collisions with others of the same name.
Namespaces also can be used to limit access.
HP WBEM Services installs with four pre-defined namespaces.
• root (in /root directory): The root namespace exists to conforms to the
DMTF specifications.
• root#cimv2 (in /root/cimv2): The standard CIM schemas go here.
Also, the schemas for the bundled providers.
• root#PG_Interop (in /root/PG_Interop): This is for provider
registration. This space is reserved exclusively for providers, and all
providers must register here. (See cimprovider man page.)
• root#PG_Internal (in /root/PG_Internal): This is a private space, for
use by HP WBEM Services only.