diff --git a/man/bootup.xml b/man/bootup.xml
index 4641e86e10..28f14891d9 100644
--- a/man/bootup.xml
+++ b/man/bootup.xml
@@ -160,6 +160,45 @@ emergency.service | | |
later in boot.
+
+ User manager startup
+
+ The system manager starts the user@uid.service unit
+ for each user, which launches a separate unprivileged instance of systemd for each
+ user — the user manager. Similarly to the system manager, the user manager starts units which are pulled
+ in by default.target. The following chart is a structural overview of the well-known
+ user units. For non-graphical sessions, default.target is used. Whenever the user
+ logs into a graphical session, the login manager will start the
+ graphical-session.target target that is used to pull in units required for the
+ grahpical session. A number of targets (shown on the right side) are started when specific hardware is
+ available to the user.
+
+
+ (various (various (various
+ timers...) paths...) sockets...) (sound devices)
+ | | | |
+ v v v v
+ timers.target paths.target sockets.target sound.target
+ | | |
+ \______________ _|_________________/ (bluetooth devices)
+ \ / |
+ V v
+ basic.target bluetooth.target
+ |
+ __________/ \_______ (smartcard devices)
+ / \ |
+ | | v
+ | v smartcard.target
+ v graphical-session-pre.target
+ (various user services) | (printers)
+ | v |
+ | (services for the graphical sesion) v
+ | | printer.target
+ v v
+ default.target graphical-session.target
+
+
+
Bootup in the Initial RAM Disk (initrd)
The initial RAM disk implementation (initrd) can be set up