Operating System Device Recognition

Hardware Detection

• When connecting a new device (e.g., USB printer, Bluetooth headphones), the computer physically detects the change in hardware.
• USB devices signal the computer to the new connection through a change in voltage on the USB bus.
• Bluetooth devices establish a connection by sending out radio signals that the computer's Bluetooth adapter picks up.

Plug and Play (PnP)

• PnP is a standardized method for automatic device recognition.
• The device and OS exchange information during the PnP handshake.
• The device broadcasts information, including its device ID, class code, and vendor ID.

Device Identification

• Device ID is a unique identifier assigned to the device by the manufacturer.
• Class code identifies the general category of the device (e.g., printer class, storage device class).
• Vendor ID specifies the manufacturer of the device.

Driver Matching

• The OS uses the device information to search for a suitable driver.
• The OS might have generic drivers for common device types stored in its driver database.
• The OS might connect to online repositories (like Windows Update) to download and install the latest driver for the specific device.

Additional Considerations

• Legacy devices might not support PnP and require manual driver installation.
• Driver signing is used for security reasons, where the driver is digitally signed by a trusted source (usually the manufacturer) to ensure its legitimacy.