[prosaic-hacker]

This is not a topic that can be explained while standing on one foot. It is a multi layer cake of hand-offs of information similar to the ISO OSI model of networking (which of course is I/O through the network.

At the top end is a program asking built in function or library to print some text. Many layers down is the final hardware receiving the text and displaying it. These two video will cover the lower layers

https://www.youtube.com/playlist?list=PLowKtXNTBypFWff2QjXCW...

https://www.youtube.com/playlist?list=PLowKtXNTBypFbtuVMUVXN...