Der init-Prozeß läuft in einer Endlosschleife, erzeugt getty-Prozesse (,,get terminal'' oder ,,get tty'') und führt Buch darüber, welcher getty-Prozeß welches Terminal eröffnet.
Algorithmus zum Einloggen
algorithm login /* procedure for logging in */
{
getty process executes;
set process group (setpgrp system call);
open tty line; /* sleeps until opened */
if (open successful)
{
exec login program;
prompt for user name;
turn off echo, prompt for password;
if (successful) /* matches password in /etc/passwd */
{
put tty in canonical mode (ioctl);
exec shell;
}
else
count login attempts, try again up to a point;
}
}