sysfs -> /sbin/hotplug -> udev

[esmith]

A quick FYI for anyone who is interested

sysfs -> /sbin/hotplug -> udev

Behind udev is an interesting idea called sysfs ( formerly known as 
"driverfs" ). Sysfs keeps track of devices coming and going, and, when 
needed, calls /sbin/hotplug which then notifies udev to handle the 
creation and removal of /dev entries. This allows the kernel and 
userland to each handle their own issues.

A short explanation of sysfs, possibly with errors

Sysfs was originally called driverfs because the intent was to provide 
information to userland about device drivers for the purpose of 
debugging them. However, it grew into the idea of using the same scheme 
for a separate vmfs, modfs, and fsfs. These merged into the one sysfs 
Linux has now, and is presently in the process of consuming devfs.

Sysfs, in the Linux world, removes extraneous information from their 
procfs. This generates some confusion because, at first glance, some 
people make the mistake of thinking that sysfs replaces procfs, which it 
does not. Sysfs and procfs are complimentary, so each provides unique 
information to userland.

This results in Linux having a single location for information about 
kernel objects/attributes and other effects, such as allowing for the 
unification of boot parameters.