A user attempting to make a connection generates a signal that is routed by the hardware to the getty process (derived from "get a tty") for one of the TTY line files in /dev. getty responds by sending an entry from the file /etc/gettydefs down the line. The gettydefs entry used depends on the <speed> argument used with the getty command. (In the SYNOPSIS of the getty(1M) reference page, the argument name is <speed>, but it is really a pointer to the <label> field of a gettydefs entry.) If no <speed> argument is provided, getty uses the first entry in gettydefs. Among the fields in the gettydefs entry is the login prompt (described in "Checking Line Settings Using IRIX Shell Commands").
On receiving the login prompt, the user enters a login name. getty starts login, using the login name as an argument. login issues the prompt for a password, evaluates the user's response, and if the password is acceptable, calls in the user's shell as listed in the /etc/passwd entry for the login name. If no shell is named, /bin/sh is furnished by default.
/bin/sh executes /etc/profile and then executes the user's .profile, if it exists. The .profile or .login file often contains stty commands that reset terminal options that differ from the defaults. /bin/csh executes /etc/cshrc, .cshrc, and .login. The connection between the user and the IRIX system has now been made.