Solaris

I am aware that Xsession gets started as part of the user login. But I see that the Xsession that is started at login, goes away and a new one is started at a later time. Does anyone know how this can happen? It seems that a fbconsole process also get started at the same time.

The XDM or console login X session is not the only sort. The X session is really on the Xserver, which in general might not even be local. Any sort of X process can attach to it regardless of the existence of a login. For instance, without a login, you could:

Code:

ssh user@host '. ./.profile;xterm -e "an application"'

Maybe your question is more about the login process. One X app can spawn another and then terminate. The X Server defines which X using client process is part of which "X Session", which is every X client attached to that display. If the display server is not taken down between logins, then X clients of the prior login could persist on it. For the console, the text on the screen and that shell need a new home on the face of the X display, and generally that process is critical to the X Server, being the parent, so if you kill that window, you lose the whole x window desktop, and when X clients lose their connection to the X Server, they tend to exit.