A driver object may have multiple device objects connected to it. The list of device objects represents the physical, logical, and virtual devices that are controlled by the driver. For example, each sector of a hard disk has a separate device object with sector-specific information. However, the same hard disk driver is used to access all sectors. When a driver is unloaded from the system, the I/O Manager uses the queue of device objects to determine which devices will be affected by the removal of the driver.