henry (03/18/83)
There is an interesting bit of code in the V7 tty driver. The flushtty() routine turns off the "stopped" bit used for stop/start handshaking. This is very entertaining if your terminal really does expect the cpu to honor this protocol all the time. This routine is called at the following times: final close of the device TIOCSETP TIOCFLUSH interrupt or quit character input queue overflow At final-close time, this is arguably reasonable, since in theory you no longer care what the device does. Maybe. (In any event, the very next line of ttyclose() after the flushtty() call gives the same effect.) At the other times, it can be a disaster. It's a mystery why this doesn't cause trouble more often; I discovered it when tracking down the cause of some ugly misbehavior by a printer which is being run off a tty line temporarily. Can anyone suggest circumstances in which this apparent botch yields useful behavior? I can't. Reply by mail, please; I'll summarize responses for the net.