Re: USB-serial adapter suggestions needed

From: bob prohaska <fbsd_at_www.zefox.net>
Date: Fri, 12 Jan 2024 19:18:23 UTC
On Fri, Jan 12, 2024 at 10:34:11AM -0800, Mark Millard wrote:
> 
> If you did not specify the signal explicitly, you tried:
> 
>      15    SIGTERM          terminate process    software termination signal
> 
> (I'm not claiming all those "terminate process" signals are
> likely to be involved. But SIGTERM is need not be involved
> at all.)
> 
> > Both the ssh connection from workstation to terminal
> > server and the su to root needed to run tip survive.
> > 
> > I should apologize for not testing this sooner, it
> > was a very easy experiment. If you think of useful
> > variations please indicate them.
> 
> See above, in particular SIGHUP .
> 

Just tried SIGHUP several times. The ssh connection didn't
disconnect. There were also no reports about overriding stale
locks. 

Using SIGKILL reported:

login: Killed
             root@nemesis:/home/bob # 
root@nemesis:/home/bob # tip ucom
Stale lock on cuaU0 PID=45604... overriding.
connected


FreeBSD/arm (ns2.zefox.net) (ttyu0)
but the ssh session and su survived.

Finally, I tried SIGSTOP. Again, ssh and su stayed up, but
restarting tip reported:
all ports busy
Power-cycling the usb-serial adpter with usbconfig
isn't able to free the port. That's new-to-me behavior.
Deleting the /dev/cuaU0-related files didn't help.

Not sure what to make of this, except that ssh survives
exit of tip, graceful or not.  

Thanks for reading!

bob prohaska