“System restart required” flag, who sets it and why? How to read it? [duplicate]

Question

This question already has an answer here:

• How can I tell what package requires a reboot of my system? 3 answers

When you log into Ubuntu (10.04 in my case), you get to see this notice saying:

*** System restart required ***

Now, I'm wondering what system component sets it and why it gets set? Using ksplice I'm aware that it can also be reset so the notice is not shown - also, since I use ksplice and after inspecting my logs there was no security upgrade of the kernel in some days, I'm wondering why it is now shown. Is the recent dbus update for 10.04 the reason?

Last but not least: how do I read that "flag", e.g. in a script?

Answer 1

Possible duplicate of How can I tell what package requires a reboot of my system?