There is an option of autoloading kernel modules:

No longer su to root, insmod the module of choice, and then start the
debugger as user-joe, but just start the debugger, and the necessary
modules get loaded automatically.

What do you have to do?
    * You need to copy the device driver code to
        /lib/modules/<kernel-version>/misc,
    * edit /etc/conf.modules 
        (see my local /etc/conf.modules as an example)
    * do a depmod -a.
    * Start kerneld at an early boot stage.

For more details on dynamic kernel module support, see the READMEs
in the latest modules utilities. The current release is modules-2.0.

The bdm driver checks if the required ressources (here only the io-port 
addresses) are in use, e.g. by the lp device driver or a parallel port 
ethernet device. When everything is free, it reserves these ressources, and
releases them when closing the device. So no double access should be possible.
