X Window Startup

http://frostyplanet.blogbus.com/logs/4057402.html
http://www.3800zz.com/tech/sjk/200910/tech_65921.html
http://info.52z.com/html/26120.html
http://120.105.184.250/peiyuli/unix/X_Window.htm
http://www.redhat.com/docs/manuals/linux/RHL-7.3-Manual/ref-guide/s1-x-runlevels.html
http://www.csie.nctu.edu.tw/~tsaiwn/course/introcs/history/rcs-cookie/phi.sinica.edu.tw/aspac/reports/94/94025/xintro5.html
http://blog.roodo.com/thinkingmore/archives/1344820.html
http://wiki.ubuntu.org.cn/index.php?title=UbuntuWiki:X/NonGraphicalBoot&variant=zh-hant

2 ways:
Runlevel 3: startx (xinit)
.xinitrc
/etc/X11/xinit/xinitrc(.Xresources, .Xmodmap, and .Xkbmap, /etc/X11/xinit/xinitrc.d/*, .Xclients)
.xserverrc
/etc/X11/xinit/xserverrc

Runlevel 5: prefdm (xdm/gdm/kdm)
/etc/sysconfig/desktop (Display Manager)
/etc/X11/xdm/Xserver
/etc/X11/xdm/Xsessions
/etc/X11/xinit/xinitrc
/etc/X11/xinit/xinitrc-common
/etc/X11/xinit/xinitrc.d/*