The loadext subroutine is used to load and unload device drivers. The name of the device driver is passed as a parameter to the loadext routine. If the device driver is located in the /usr/lib/drivers directory, just the device driver name without path information can be specified to the loadext subroutine. If the device driver is located in another directory, the fully qualified path name of the device driver must be specified.
The Device Driver Name descriptor of Predefined Devices (PdDv) object class objects is intended to contain only the device driver name and not the fully qualified path name. For device drivers located in the /usr/lib/drivers directory, a Configure method can obtain the name of the driver from the Device Driver Name descriptor to pass to the loadext routine. This is convenient since most drivers are located in the /usr/lib/drivers directory.
If a device driver is located in a directory other than the /usr/lib/drivers directory, the path name must be handled differently. The Configure method could be coded to assume a particular path name, or for more flexibility the path name could be stored as an attribute in the Predefined Attribute (PdAt) object class. The Configure method is responsible for knowing how to obtain the fully qualified path name to pass to the loadext subroutine.
| /usr/lib/drivers directory | Contains device drivers. |
ODM Device Configuration Object Classes.
The loadext subroutine.
Predefined Devices (PdDv) object class, Predefined Attribute (PdAt) object class.