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5.2.9 IBM’s AIX Operating System

Chris Lewis, Harald Milz and Michael Staats have done excellent work on porting mgetty to AIX. Since then, I have taken over and actively use mgetty+sendfax on AIX for customer systems, and everything is very well tested now.

On AIX, many people do not want to manipulate /etc/inittab directly, instead, use some system administration tools (like ’smit’). To ease mgetty installation on AIX, Michael Staats has provided a small shell script, inittab.aix, that will help you setup your inittab after you’ve run make install. Just call it with the name of the tty you’re modem is connected to, e.g.

./inittab.aix tty0.

I have received a couple of problem reports on AIX 4.1 where “suddenly” the modem line stopped working and all mgetty reported were error messages. If that happens to you, set toggle-dtr no in mgetty.config. AIX 4.1 doesn’t seem to like programs that fiddle with the modem control lines.

Christoph Brinck ( has also reported that it’s necessary to enable the “dtropen line discipline” for the serial line you’re using (whatever that may mean). This is done with the command:

chdev -l 'tty1' -a flow_disp='rts'
chdev -l 'tty1' -a open_disp='dtropen'

or via the ‘chgtty’ part of SMIT (but I think that’s the default setting for new ttys anyway).

Hardware and Software flow control work fine on AIX 3.x and AIX 4.x now.