Subject: I want to run without console
To: None <>
From: Gordon W. Ross <>
List: port-sun3
Date: 06/16/1995 10:13:49
> From: Tomas Tengling <>
> Date: Fri, 16 Jun 1995 00:05:21 +0200 (MET DST)

> Hi,
> I want to run my diskless NetBSD sun3/50 without console as we are
> short of serial terminals.  When I used to run SunOS diskless it was
> no problems to boot it without the serial console and if I would boot it
> with the console plugged in it was no problem to unplug it (hot).
> But with NetBSD it stops when I unplug the console and it will not
> boot without console.  Is there any way of succeed with this?

Both SunOS and NetBSD on the sun3 are sensitive to "line break"
on the tty port when used as the console.  That is how you drop
into the PROM or kernel debugger.  Unplugging a terminal usually
will cause a line break.  To prevent this, you could wire up a
plug with the data line held inactive and keep that in place of
the terminal.  I think wiring for such a plug has been presented
in one of the sun newsgroups (i.e. comp.sys.sun.admin).

Gordon Ross