PATH
The CFM requires that a fragment import any libraries that it is dependent on. Generic drivers link to the Driver Services Library; family drivers may also be linked to family libraries. The linking lets the fragment's symbols be bound at load time. The Driver Services Library or a family library should be used instead of a Toolbox-based library when linking a device driver.
Native device drivers should use the CFM's import library mechanism to share code or data. With this technique, the CFM creates an import library fragment when the first driver is loaded. When another driver is loaded, it establishes a connection to the existing library, letting the two drivers share code or data. For further information about the CFM, see Inside Macintosh: PowerPC System Software. This book is listed in Apple Publications.
In the past, driver imports have not always been rigidly characterized. The reason for now explicitly specifying the system entry points available to native drivers is to guarantee compatibility of drivers with future releases of Mac OS. For a further discussion, see Driver Services Library. See also the family-specific information in Chapters 13, 14, and 15.