The USBA 2.0 framework is a service layer that presents an abstract view of USB devices to USBA-compliant client drivers. The framework enables USBA-compliant client drivers to manage their USB devices. The USBA 2.0 framework supports the USB 2.0 specification except for high speed isochronous pipes. For information on the USB 2.0 specification, see http://www.usb.org/home.
The USBA 2.0 framework is platform-independent. The Solaris USB architecture is shown in the following figure. The USBA 2.0 framework is the USBA layer in the figure. This layer interfaces through a hardware-independent host controller driver interface to hardware-specific host controller drivers. The host controller drivers access the USB physical devices through the host controllers they manage.