Serial programming on FreeBSD 6.0 RELEASE

David Kelly dkelly at
Thu Jun 22 18:51:16 UTC 2006

On Thu, Jun 22, 2006 at 12:19:41PM -0600, Andrew Falanga wrote:
> Derek,
> No I didn't disable the getty on the port.  To be honest, I didn't know one
> was running.

Its not going to be running by default. Even if it was then it would be
on /dev/ttyd1 not /dev/cuad1. What is supposed to happen is that getty
can listen for incoming on /dev/ttyd1 but if it doesn't have an active
connection it would be set aside while another comes along on the
call-out device to use the port. If ttyd1 is busy attempts to open cuad1
should fail.

> Second, the errors I'm receiving are:
> sio1: 2 more silo overflows (total 9)
> sio1: 280221 more tty-level buffer overflows (total 576898)

Believe this is saying the data arrived and nobody picked it up.

> One question I have is, why would kermit able to receive/send data
> across the port?  I don't know if said this in my first message, but I
> started kermit on both the FreeBSD and Linux machines and was able to
> send/receive data in either direction.  I didn't disable getty before
> doing that.

/dev/cuad1 is rw for uucp:dialer and nothing for anyone else. What ID is
running your code? Generally one places users who are permitted to use
the serial ports into group dialer. Furthermore kermit needs the user's
uucp group permissions in order to create the UUCP lock in the hopes
that other programs will honor kermit's word that the device is busy.

David Kelly N4HHE, dkelly at
Whom computers would destroy, they must first drive mad.

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