I was going through the source code of Linux version 0.0.1. In the kernel source directory saw a file tty_io.c. What is the role of this file/tty in Linux kernel?
In Unix systems, a tty (which is short for "teletypewriter") is the standard representation of a terminal device, with at least input and output capabilities and usually much more. These were originally connected to serial ports, but most today are virtual terminals, connected to either a text-mode console (DOS-like) or a graphical terminal program (like xterm or gnome-terminal).