USBenhetsdrivere

USB device drivers are software components that enable an operating system to interact with USB devices. They translate USB protocol commands into operating system I/O operations, manage device enumeration, configuration, data transfer, and handle power management and error recovery. The driver ensures that a connected device can communicate with applications and the system hardware in a consistent and safe manner.

In a typical system, USB hardware provides a host controller (such as xHCI, EHCI, OHCI, or UHCI) that interfaces with the CPU. The USB stack in the operating system includes a host controller driver, a USB core, and class or vendor-specific drivers. When a device is connected, the host controller enumerates it, assigns a USB address, and reads its descriptors to determine capabilities. If a standard class driver exists—for example HID for keyboards and mice, Mass Storage for USB flash drives, or Audio for sound devices—the OS can bind that driver. If not, a vendor-specific driver or a generic USB driver may be used.

USB drivers can be implemented as kernel-mode or user-mode components, depending on the operating system and device requirements. Windows uses a comprehensive kernel USB stack with class drivers; Linux provides a centralized USB subsystem in the kernel; macOS relies on the IOKit framework for USB device management. Some devices present multiple interfaces requiring cooperation between different drivers, a situation common with composite devices. USB also includes power management features that allow devices to draw power from the bus and negotiate higher power levels when needed.

Development and distribution: manufacturers provide drivers to support their devices, while operating systems supply built-in drivers for common USB classes. Driver signing and security policies govern which drivers can be loaded. Users may troubleshoot by re-plugging devices, updating drivers, or using vendor utilities.