Suppose, for example, an object represents a SCSI device. How should that object deal with the SCSI interface? Should it call a function of some SCSI manager? In a system with more than one SCSI bus, such as a personal computer with optional SCSI cards, this represents a problem because the traditional approach assumes only one SCSI manager. The driver that knows where to find the SCSI interface can't deal with this situation. The traditional approach forces a complicated fix that makes multiple buses look like one bus.
If the SCSI bus is an object, however, that gets passed to the SCSI device object when it is created, the SCSI device doesn't need knowledge of how to find the resource (the SCSI bus)--it lets the resource find it.
For more information about working with resources, see "Let resources find you" on page 34.