Have a look at these two URL's:
- The Linux Boot Process
- The Red Hat Linux Boot Process
The first one gives a global overview of the boot process, booting is done in the order shown. The second link is RedHat (Cent OS) specific, a more detailed explanation based on a RedHat system.
) messages you talk about are part of the later stages (init/runlevels). As you might have seen by know, the booting process is not done with one specific file.
Hope this clears things up a bit.