PATH
The Name Registry provides a unified way of identifying or obtaining information about many system resources, not just about devices. When writing a device driver, never acquire information from low memory or through Toolbox API calls because doing so may prevent your driver from being compatible with future Mac OS releases. Instead, use the Name Registry to acquire the information. During driver initialization, family experts facilitate this process by passing each driver a RegEntryID representing its physical device. By using the RegEntryID and the Name Registry a device driver can find all the information it is likely to need.
For further information about the Name Registry, see Name Registry