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USB Drivers

A Universal Serial Bus Services Library layer provides hardware abstraction. Below it is the UIM (USB Interface Module) that communicates with the USB hardware in the KeyLargo IC. Above it are the class drivers that are loaded dynamically when new devices are plugged onto the bus.

USB class drivers are software components that are able to communicate with similar USB devices of a particular kind. If the appropriate class driver is present, any number of compliant devices can be plugged in and start working immediately without the need to install additional software.

Mac OS 8.6 includes the following class drivers:

Audio class driver: supports USB audio devices such as speakers and microphones. The Sound Manager has been modified to control volume, mute, bass, and treble for USB speakers. Mac OS 8.6 also supports the USB Suspend and Resume functionality defined in the USB standard.
Mass Storage class driver: supports booting from a USB storage device that follows the USB Mass Storage Class specification. Mass Storage Class drivers do not support CD, CD-R, or other read-only media types.
Communication Class driver: Supports USB communication devices that support the Abstract Control Model subclass.
Printer Class driver: Supports USB printers. The LaserWriter 8 driver can communicate through this driver to any Postscript-based printer.
HID driver: Provides support in InputSprockets for all HID-class devices (such as joysticks and game controllers) and for most force feedback devices.
Keyboard and Mouse driver: Supports all USB keyboards and mouse devices that support boot protocol (HID Class, SubClass 1).
HUB Class driver: Supports all USB compliant hubs.

Version 1.3 of the Macintosh USB system software supports all four data transfer types defined in the USB specification.