The device driver commands are add_drv, rem_drv, modload, and modunload.
add_drv(1M) - Informs the system that there is a newly installed device driver.
rem_drv(1M) - Informs the system that the specified driver module is no longer valid.
modload(1M) - Loads the specified loadable module into the running system.
modunload(1M) - Unloads the specified loadable module from the running system.
