+ Before the switch to the netlink-based uevent source, this was
+ used to hook hotplug scripts into kernel device events. It
+ usually pointed to a shell script at /sbin/hotplug.
+ This should not be used today, because usual systems create
+ many events at bootup or device discovery in a very short time
+ frame. One forked process per event can create so many processes
+ that it creates a high system load, or on smaller systems
+ it is known to create out-of-memory situations during bootup.