The TTY demystified
Real teletypes in the 1940s.
The TTY subsystem is central to the design of Linux, and UNIX in general.
Unfortunately, its importance is often overlooked, and it is difficult to find
good introductory articles about it. I believe that a basic understanding of
TTYs in Linux is essential for the developer and the advanced user.
Beware, though: What you are about to see is not particularly elegant. In
fact, the TTY subsystem while quite functional from a user s point of
view is a twisty little mess of special cases. To understand how this
came to be, we have to go back in time.