it all starts as the user as one of the main feature and is you the person using the device they often have a username or sometimes use they name there are people that are power users and they can use advance features.
provides the management
it has security and integer to the operating system and to help the user work on what they need to work on without logging on as power user so they can do work but cant access the folder that the bosses.
handles system resources
is for assigning and managing and resolving persistent identifies for digital objects and other resources.