Advanced Embedded Systems Question:

Input and output devices or functions allow the user to interact with the external files. Input and output functions are used to transfer the load on the bus. It uses the multiplexes having the input and output signals that remain same. Input and output buses move at the slower rate or speed than the processor speed. This increases the problem of bottleneck or the deadlock due to poor performance. There is a possibility to send more transistors for a layout to be given. These different devices may have very different speeds of communication. When programming IO bus control, make sure to take this into account.
In some systems, memory mapped IO is used. In this scheme, the hardware reads its IO from predefined memory addresses instead of over a special bus. This means you'll have simpler software, but it also means main memory will get more access requests.