- system (i.e. <filename>/</filename>) and the virtual
- kernel API file systems such as
- <filename>/proc</filename>, <filename>/sys</filename>
- or <filename>/dev/</filename>. This service executes
- no operation if <filename>/etc/fstab</filename> does
- not exist or lists no entries for the root file system
- or the kernel API VFS.</para>
+ system (i.e. <filename>/</filename>),
+ <filename>/usr</filename> and the virtual kernel API
+ file systems such as <filename>/proc</filename>,
+ <filename>/sys</filename> or
+ <filename>/dev</filename>. This service executes no
+ operation if <filename>/etc/fstab</filename> does not
+ exist or lists no entries for the mentioned file
+ systems.</para>
+
+ <para>For a longer discussion of kernel API file
+ systems see <ulink
+ url="http://www.freedesktop.org/wiki/Software/systemd/APIFileSystems">API
+ File Systems</ulink>.</para>