The DevFS along with DevPtsFS give a complete solution for populating
device nodes in /dev. The main purpose of DevFS is to eliminate the
need of device nodes generation when building the system.
Later on, DevFS will assist with exposing disk partition nodes.
To keep track of ongoing terminal sessions, we now have a sort-of
traditional /var/run/utmp file, like other Unix systems.
Unlike other Unix systems however, ours is of course JSON. :^)
The /bin/utmpupdate program is used to update the file, which is
not writable by regular user accounts. This helper program is
set-GID "utmp".
