It's happened multiple times and I can't figure out why it's happening or how to undo it, but hitting CTRL-S seems to disable the given TTY on 'nixes of various flavors. Killing the pid doesn't bring the tty back, I end up having to use other tty's until I reboot.
Anyone got some information for me?
ctrl/S = XOFF (stop output to terminal).
The converse is ctrl/Q = XON (start output to terminal).
Thus if you type ctrl/S and the output stops, type ctrl/Q and the output will start again.
Hope this helps.
And if you have IXANY set, then ANY key will restart it.
(which is why IXANY is commonly set).