System V is Crashing

[Alan Fargusson]

> By using crash(1m) I discovered zillions of entries in the callout array
> which were to restart the printer's tty driver.  I can't remember the
> exact circumstances, but I know that the callouts looked suspect and the
> use of fill characters (add OFILL to tio.c_oflag above) for delays rather
> than callouts cured the problem immediately.

I had forgotten about that one. There is a bug in the DZ driver (dz.c)
in dzproc. The case T_OUTPUT there is a line like:
		if (tp->t_state & (BUSY|TTSTOP))

It should be:
		if (tp->t_state & (TIMEOUT|BUSY|TTSTOP))

I told someone at AT&T about it over a year ago, but I don't think they
wanted to know.
-- 

Alan Fargusson.

{ ihnp4, amdahl, mot }!drivax!alan