6/12/72 GETTY (VII)





6/12/72                                               GETTY (VII)





NAME            getty  -- set typewriter mode and get user's name



SYNOPSIS        --



DESCRIPTION     getty is invoked by init (VII) immediately after

                a typewriter is opened following a dial-in.  The

                user's login name is read and the login(I) com-

                mand is called with this name as an argument.

                While reading this name getty attempts to adapt

                the system to the speed and type of terminal be-

                ing used.



                getty initially sets the speed of the interface

                to 150 baud, specifies that raw mode is to be

                used (break on every character), that echo is to

                be suppressed, and either parity allowed.  It

                types the "login:" message (which includes the

                characters which put the 37 Teletype terminal

                into full-duplex and unlock its keyboard).  Then

                the user's name is read, a character at a time.

                If a null character is received, it is assumed to

                be the result of the user pushing the "break"

                ("interrupt") key.  The speed is then changed to

                300 baud and the "login:" is typed again, this

                time with the appropriate sequence which puts a

                GE TermiNet 300 into full-duplex.  This sequence

                is acceptable to other 300 baud terminals also.

                If a subsequent null character is received, the

                speed is changed again.  The general approach is

                to cycle through a set of speeds in response to

                null characters caused by breaks.  The sequence

                at this installation is 150, 300, and 134.5 baud.



                Detection of IBM 2741s is accomplished while the

                speed is set to 150 baud.  The user sends a 2741

                style "eot" character by pushing the attention

                key or by typing return; at 150 baud, this char-

                acter looks like the ascii "~" (174 ).  Upon re-
                                                   8
                ceipt of the "eot", the system is set to operate

                2741s and a "login: " message is typed.



                The user's name is terminated by a new-line or

                carriage-return character.  The latter results in

                the system being set to to treat carriage returns

                appropriately (see stty(II)).



                The user's name is scanned to see if it contains

                any lower-case alphabetic characters; if not, the

                system is told to map any future upper-case char-

                acters into the corresponding lower-case charac-

                ters.  Thus UNIX is usable from upper-case-only

                terminals.



                Finally, login is called with the user's name as

                argument.



FILES           /etc/getty



SEE ALSO        init(VII), login(I), stty(II)



DIAGNOSTICS     --



BUGS            --



OWNER           dmr, ken, jfo
squoze.net
