Class and Instance

In WBEM, a class is a collection of objects that represents the most basic unit of management. For example, in Sun WBEM, the three main functional classes include CIMClass, CIMProperty, and CIMInstance.

Abstractly, classes are used to create managed objects. Class characteristics are inherited by the child objects, or instances, that are created from a class. For example, using CIMClass, you can create an instance, CIMClass (Solaris_Computer_System).

This instance of CIMClass answers the question, "What is the computer system?" The value of the instance is Solaris_Computer_System. All instances of the same class type are created from the same class template. In the example, the name of the computer system provides a template to create managed objects of the type Computer_System.

Classes can be static or dynamic. Instances of static classes are stored by the CIM Object Manager and can be retrieved from the CIM Repository when a request is made. Instances of dynamic classes—classes containing data that changes regularly, such as system usage—are created by provider applications as the data changes.

Custom Classes: Extensions to CIM

For extensions to CIM, custom classes can be developed to support managed objects that are specific to their managed environment. The CIM Object Manager API provides new classes to extend CIM for the Solaris operating environment.