Serial console connection problem

Jonathan Chen jonc at
Fri Apr 8 00:45:01 PDT 2005

On Fri, Apr 08, 2005 at 09:49:49AM +0300, Jani Luukkanen wrote:

> Weird, fstat shows nothing on the port;
> root at mos root # fstat /dev/cuaa0
> USER     CMD          PID   FD MOUNT      INUM MODE         SZ|DV R/W NAME
> root at mos root #
> And yes, this is problem is on the 4.10 machine which is connecting to 
> the 5.3 one.
> Might be this is the problem, here is all gettys running on the 4.10 
> machine:

> root     238  0.0  0.1   956  516  d0  Is   16Mar05   0:00.00 
> /usr/libexec/getty std.9600 console
> The last one (console) does not appear on the 5.3 machines processlist, 
> would it be safe to kill that one just like that with kill -9 238 (If 
> that is the process locking the port)?

You have to do a bit more than this. First you have to disable the
getty on the 4.10 machine by editing /etc/ttys, and then "kill -HUP 1"
and then kill the getty if it still exists.

You then have to enable the getty on the the 5.3 box by editing
/etc/ttys and then "kill -HUP 1".

The getty has to be running on the machine that you're going to
connect *to*.

> The connection is ordinary serial cable, do you mean that should specify 
> from BSD side what kind of connection is it?
> >Make sure that you haven't got a getty running at the same time on
> >both sides, and that you've got a null-modem connection between the two
> >hosts instead of a straight thru'.
> >

Serial cables come in 2 basic flavours: straight thru' and null-modem.
A straight-thru is what you use if you want to connect the machine to
a modem. A null-modem connection is what you use if you want to
connect from host to host. If you use the wrong cable, no output will
show, and you may possibly get a device-busy message as well.

Jonathan Chen <jonc at>
                 When you don't know what you are doing, do it neatly.

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