diff --git a/chapter09/introduction.xml b/chapter09/introduction.xml
index d2a0c7435..da5ffe67c 100644
--- a/chapter09/introduction.xml
+++ b/chapter09/introduction.xml
@@ -31,7 +31,7 @@
The init program is controlled by the
/etc/inittab file and is organized into run levels that
- can be run by the user:
+ can be run by the user. In LFS, they are used as follows:
0 — halt
1 — Single user mode
diff --git a/chapter09/usage.xml b/chapter09/usage.xml
index a1c098cae..2c6529e14 100644
--- a/chapter09/usage.xml
+++ b/chapter09/usage.xml
@@ -31,7 +31,7 @@
generally not used. See init(8) for more details), and
each one of those corresponds to the actions the computer is supposed to
perform when it starts up. The default run-level is 3. Here are the
- descriptions of the different run-levels as they are implemented:
+ descriptions of the different run-levels as they are implemented in LFS:
0: halt the computer
1: single-user mode