<architecture> /i:-too-oh/ (I2O) A specification which aims to
provide an I/O device driver architecture that is
independent of both the specific device being controlled and
the host operating system. The Hardware Device Module (HDM)
manages the device and the OS Services Module (OSM) interfaces
to the host operating system. The HDM is portable across
multiple operating systems, processors and busses. The HDM
and OSM communicate via a two layer message passing
protocol. A Message Layer sets up a communications session
and runs on top of a Transport Layer which defines how the two
parties share information.
I2O is also designed to facilitate intelligent I/O subsystems,
with support for message passing between multiple
independent processors. By relieving the host of interrupt
intensive I/O tasks required by the various layers of a driver
architecture, the I2O intelligent I/O architecture greatly
improves I/O performance. I2O systems will be able to more
efficiently deliver the I/O throughput required by a wide
range of high bandwidth applications, such as networked
video, groupware and client-server processing. I2O does
not restrict where the layered modules execute, providing
support for single processor, multiprocessor, and
clustered systems.
I2O is not intended to replace the driver architectures
currently in existence. Rather, the objective is to provide
an open, standards-based approach, which is complementary to
existing drivers, and provides a framework for the rapid
development of a new generation of portable, intelligent I/O.
