An I O System for Mach

The Mach I O system represents a radical departure from its predecessor Mach which relied on the BSD Unix model of device management The I O interface in Mach sup ports device drivers that are largely device independent implemented at user level and location independent Our approach to device management signi cantly reduces the size of the kernel s machine dependent code enables us to reduce the length of the I O path and permits us to transparently manage remote devices on non shared memory multiprocessor architectures such as the Hypercube This paper describes the structure and performance of Mach s I O system