Hello.

Justin Zygmont wrote:
>> - Client-server approach for port I/O, which allows 
> I wonder if this is why there is a lock file problem with
> a modem now?
No, this has nothing to do with locks.
However there is a bug in a serial code
which, but only in case open() fails,
prints a misleading message that the device
is already locked, and leaves a stale lock
file.
The fix is attached. This may not be the
problem you see however. I have no idea
what you see actually, as you have provided
no details. But as I already have a fix to
something similar - try it and maybe it will
help.