Device classes

Managing devices requires the operating system to comprehend what device connections are allowed. The operating system classifies devices hierarchically into three groups.

These groups are:

• Functional classes
• Functional subclasses
• Device types

Functional classes consist of devices that perform the same function. Printers, for example, comprise a functional class. Functional classes are grouped into subclasses according to certain device similarities. For example, printers have a serial or parallel interface. Serial printers are one subclass and parallel printers are another. Device types are classified according to their model and manufacturer.

Device classes define valid parent-child connections for the operating system. The hierarchy defines the possible subclasses that can be connected for each of the possible child connection locations. For example, the term RS-232 8-port adapter specifies that only devices belonging to the RS-232 subclass can be connected to any of the eight ports of the adapter.

Device classes and their hierarchical dependencies are maintained in an Object Data Manager (ODM) Device Configuration database.