The Plug and Play (PnP) manager and Setup use device identification strings to identify devices that are installed in a computer.

Setup uses the following device identification strings to locate the information (INF) file that best matches the device. These strings are reported by a device's enumerator:

• Device IDs
• Hardware IDs
• Compatible IDs

A device has only one device ID that is the most specific ID for a device. A device can also have less specific hardware IDs and compatible IDs. Setup first tries to find an INF file that matches the device ID. If it does not find such a match, Setup next tries to find a match to one of the less specific hardware IDs or compatible IDs. For more information about how Setup uses these IDs to match a device to an INF file, and how to specify IDs in an INF file, see How Setup Selects Drivers.

In addition to using the preceding IDs to identify devices, the PnP manager uses the following IDs to uniquely identify instances of each device that are installed in a computer:

• Instance IDs
• Device instance IDs

Starting with Windows 7, the PnP manager uses the Container ID device identification string to group one or more device nodes (devnodes) that were enumerated from each instance of a physical device installed in a computer:

Each enumerator customizes its device IDs, hardware IDs, and compatible IDs to uniquely identify the device that it enumerates. In addition, each enumerator has its own policy to identify hardware IDs and compatible IDs. For more information about hardware ID and compatible ID formats for most of the system buses, see Device Identifier Formats.