- there is only a limited number of ttys. Try the fuser command on all of them to find out which process(es) is(are) using it. The examine the found processes.
Some starting ideas:
- process table with ps -ef and check entries using a tty
- lslpp -h to find out if there is a package installed at some given date
I am not sure what you mean by "unavailable": every device in AIX is basically in one of two states (if present at all): do a lsdev -C and you should see a list of devices some of which are in state...
Does the software write to tty00 or to /dev/console? You can redirect the system console through the smit menus to tty02, but sadly I don't have a server available to walk...
If you run PuTTY (a terminal emulator free download) from the console and connect it to /dev/tty?? (without the application running which grabs that port) you should be able to see traffic arriving...