The I/O subsystem of a computer provides an efficient mode of communication between the central system and the outside environment. It handles all the input-output operations of the computer system

Input or output devices that are connected to computer are

These devices are designed to read information into or out of the memory unit upon command from the CPU and are considered to be the part of computer system

peripheral devices are also called peripherals

Allows information output, from the computer to the outside world

Allows both input(from outside world to computer) as well as, output(from computer to the outside world)

Allows user input, from the outside world to the computer.

Example: Touch screen etc.

Example: Printer, Monitor etc

Example: Keyboard, Mouse etc

I/O subsystems include

is a set of wires that acts as a shared data path to connect multiple subsystems within the system

A bus consists of multiple lines allowing parallel movements of bits

Buses are …. cost & ….

It is hard to connect new devices to each other and to the system

At any one time only one device may use the bus

The speed of the bus is affected by

connect a number of devices, requiring these devices to share the bus

multipoint bus