quartz/content/notes/23-IO-systems.md

title	aliases	tags
23-IO-systems		cosc204 lecture

interactive between device drivers and IO devices

Hardware

• IO device linked to machine via Port
• link is a set of wires called a Bus
• as each end of the link is a device controller (basically a process)
• 

device controller registers

• each contoller has registers for holding signals
• CPU can read and write these
• some hold data some control signals

adressesing devices

• each port has an address range
• CPU can issue IO instructions to particular addresses
• communication can be 1 byte at a time for via direct memory access

Kernel interface

Performance